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Seizures

MedGen UID:
409523
Concept ID:
C1959629
Finding
Synonyms: Epilepsy; Seizure; seizures
 
HPO: HP:0001250

Term Hierarchy

CClinical test,  RResearch test,  OOMIM,  GGeneReviews
  • CROGSeizures

Conditions with this feature

Lipomatosis dolorosa
MedGen UID:
1757
Concept ID:
C0001529
Disease or Syndrome
Adiposis dolorosa, also known as Dercum disease, is characterized by generalized obesity and pronounced, disabling, and chronic pain in the adipose tissue of the proximal extremities, trunk, pelvic area, and buttocks; the face and hands are usually spared. There are a number of associated symptoms, including multiple lipomas, generalized weakness, fatigue, sleep disturbances, constipation, and psychiatric abnormalities. It is 5 to 30 times more common in women than men, and usually presents between 35 and 50 years of age (summary by Campen et al., 2001; review by Hansson et al., 2012). Based on a review of the literature and studies of 111 patients, Hansson et al, (2012) proposed a classification of Dercum disease into 4 types: (I) generalized diffuse form without clear lipomas, (II) generalized nodular form with multiple lipomas, (III) localized nodular form, and (IV) juxtaarticular form with solitary fatty deposits near joints.
Fabry's disease
MedGen UID:
8083
Concept ID:
C0002986
Disease or Syndrome
Fabry disease results from deficient activity of the enzyme a-galactosidase (a-Gal A) and progressive lysosomal deposition of globotriaosylceramide (GL-3) in cells throughout the body. The classic form, occurring in males with less than 1% a-Gal A enzyme activity, usually has its onset in childhood or adolescence with periodic crises of severe pain in the extremities (acroparesthesias), the appearance of vascular cutaneous lesions (angiokeratomas), sweating abnormalities (anhydrosis, hypohydosis, and rarely hyperhidrosis), characteristic corneal and lenticular opacities, and proteinuria. Gradual deterioration of renal function to end-stage renal disease (ESRD) usually occurs in men in the third to fifth decade. In middle age, most males successfully treated for ESRD develop cardiac and/or cerebrovascular disease, a major cause of morbidity and mortality. Heterozygous females typically have milder symptoms at a later age of onset than males. Rarely, they may be relatively asymptomatic throughout a normal life span or may have symptoms as severe as those observed in males with the classic phenotype. In contrast, males with greater than 1% a-Gal A activity may have either (1) a cardiac variant phenotype that usually presents in the sixth to eighth decade with left ventricular hypertrophy, mitral insufficiency and/or cardiomyopathy, and proteinuria, but without ESRD; or (2) a renal variant phenotype, associated with ESRD but without the skin lesions or pain.
Ataxia-telangiectasia syndrome
MedGen UID:
439
Concept ID:
C0004135
Congenital Abnormality
Ataxia-telangiectasia (AT) is an autosomal recessive disorder characterized by cerebellar ataxia, telangiectases, immune defects, and a predisposition to malignancy. Chromosomal breakage is a feature. AT cells are abnormally sensitive to killing by ionizing radiation (IR), and abnormally resistant to inhibition of DNA synthesis by ionizing radiation. The latter trait has been used to identify complementation groups for the classic form of the disease (Jaspers et al., 1988). At least 4 of these (A, C, D, and E) map to chromosome 11q23 (Sanal et al., 1990) and are associated with mutations in the ATM gene.
Autistic disorder of childhood onset
MedGen UID:
13966
Concept ID:
C0004352
Mental or Behavioral Dysfunction
Autism comprises a clinically heterogeneous group of disorders – collectively referred to as “autism spectrum disorders” (ASD) – that share common features of impaired social relationships, impaired language and communication, and repetitive behaviors or a narrow range of interests. For most children with autism, symptoms develop gradually, although approximately 30% have a "regressive" onset usually between ages 18 and 24 months. About 50%-70% of children with autism are identified as intellectually disabled by nonverbal IQ testing and approximately 25% develop seizures. Autism can be considered complex (i.e., presence of dysmorphic features and/or microcephaly) or essential (i.e., absence of physical abnormalities and microcephaly). About 25% of children who fit the diagnostic criteria for ASD at age two to three years subsequently begin to talk and communicate, and by age six to seven years blend to varying degrees into the regular school population. The remaining 75% have lifelong disability requiring intensive parental, school, and social support.
Gorlin syndrome
MedGen UID:
2554
Concept ID:
C0004779
Neoplastic Process
Nevoid basal cell carcinoma syndrome (NBCCS) is characterized by the development of multiple jaw keratocysts, frequently beginning in the second decade of life, and/or basal cell carcinomas (BCCs) usually from the third decade onward. Approximately 60% of individuals have a recognizable appearance with macrocephaly, bossing of the forehead, coarse facial features, and facial milia. Most individuals have skeletal anomalies (e.g., bifid ribs, wedge-shaped vertebrae). Ectopic calcification, particularly in the falx, is present in more than 90% of affected individuals by age 20 years. Cardiac and ovarian fibromas occur in approximately 2% and 20% of individuals respectively. Approximately 5% of children with NBCCS develop medulloblastoma (primitive neuroectodermal tumor [PNET]), generally the desmoplastic subtype. Peak incidence is at age two years. Life expectancy in NBCCS is not significantly different from average.
Behcet's syndrome
MedGen UID:
2568
Concept ID:
C0004943
Disease or Syndrome
Behçet disease is an inflammatory condition that affects many parts of the body. The health problems associated with Behçet disease result from widespread inflammation of blood vessels (vasculitis). This inflammation most commonly affects the mouth, genitals, skin, and eyes. Painful mouth sores called aphthous ulcers are usually the first sign of Behçet disease. These sores occur on the lips and tongue and inside the cheeks. The ulcers look like common canker sores, and they typically heal within one to two weeks. About 75 percent of all people with Behçet disease develop similar ulcers on the genitals. These ulcers occur most frequently on the scrotum in men and on the labia in women. Behçet disease can also cause painful bumps and sores on the skin. Most affected individuals develop pus-filled bumps that resemble acne. These bumps can occur anywhere on the body. Some affected people also have red, tender nodules called erythema nodosum. These nodules usually develop on the legs but can also occur on the face, neck, and arms. An inflammation of the eye called uveitis is found in more than half of people with Behçet disease. Eye problems are more common in younger people with the disease and affect men more often than women. Uveitis can result in blurry vision and an extreme sensitivity to light (photophobia). Rarely, inflammation can also cause eye pain and redness. If untreated, the eye problems associated with Behçet disease can lead to blindness. Less commonly, Behçet disease can affect the joints, gastrointestinal tract, large blood vessels, and brain and spinal cord (central nervous system). Central nervous system abnormalities are among the most serious complications of Behçet disease. Related symptoms can include headaches, confusion, personality changes, memory loss, impaired speech, and problems with balance and movement. The signs and symptoms of Behçet disease usually begin in a person's twenties or thirties, although they can appear at any age. Some affected people have relatively mild symptoms that are limited to sores in the mouth and on the genitals. Others have more severe symptoms affecting many parts of the body, including the central nervous system. The features of Behçet disease typically come and go over a period of months or years. In most affected individuals, the health problems associated with this disorder improve with age.
Celiac disease
MedGen UID:
3291
Concept ID:
C0007570
Disease or Syndrome
Celiac disease is a systemic immune disease that can be associated with gastrointestinal findings (diarrhea, weight loss, abdominal pain, anorexia, lactose intolerance, abdominal distention, and irritability) and/or highly variable non-gastrointestinal findings (iron-deficiency anemia, dermatitis herpetiformis, chronic fatigue, joint pain/inflammation, migraines, depression, attention-deficit disorder, epilepsy, osteoporosis/osteopenia, infertility and/or recurrent fetal loss, vitamin deficiencies, short stature, failure to thrive, delayed puberty, dental enamel defects, and autoimmune disorders). Classic celiac disease, characterized by mild to severe gastrointestinal symptoms, is less common than nonclassic celiac disease, characterized by absence of gastrointestinal symptoms.
Chédiak-Higashi syndrome
MedGen UID:
3347
Concept ID:
C0007965
Disease or Syndrome
Chediak-Higashi syndrome (CHS) is characterized by partial oculocutaneous albinism (OCA), immunodeficiency, and a mild bleeding tendency. Approximately 85% of affected individuals develop the accelerated phase, a lymphoproliferative infiltration of the bone marrow and reticuloendothelial system. All affected individuals including adolescents and adults with atypical CHS and children with classic CHS who have successfully undergone allogenic hematopoietic stem cell transplantation (HSCT) develop neurologic findings during early adulthood.
Crouzon syndrome
MedGen UID:
1162
Concept ID:
C0010273
Disease or Syndrome
The eight disorders comprising the FGFR-related craniosynostosis spectrum are Pfeiffer syndrome, Apert syndrome, Crouzon syndrome, Beare-Stevenson syndrome, FGFR2-related isolated coronal synostosis, Jackson-Weiss syndrome, Crouzon syndrome with acanthosis nigricans (AN), and Muenke syndrome (isolated coronal synostosis caused by the p.Pro250Arg mutation in FGFR3). Muenke syndrome and FGFR2-related isolated coronal synostosis are characterized only by uni- or bicoronal craniosynostosis; the remainder are characterized by bicoronal craniosynostosis or cloverleaf skull, distinctive facial features, and variable hand and foot findings.
Crigler Najjar syndrome, type 1
MedGen UID:
41346
Concept ID:
C0010324
Disease or Syndrome
Crigler-Najjar syndrome is a severe condition characterized by high levels of a toxic substance called bilirubin in the blood (hyperbilirubinemia). Bilirubin is produced when red blood cells are broken down. This substance is removed from the body only after it undergoes a chemical reaction in the liver, which converts the toxic form of bilirubin (called unconjugated bilirubin) to a nontoxic form called conjugated bilirubin. People with Crigler-Najjar syndrome have a buildup of unconjugated bilirubin in their blood (unconjugated hyperbilirubinemia). Bilirubin has an orange-yellow tint, and hyperbilirubinemia causes yellowing of the skin and whites of the eyes (jaundice). In Crigler-Najjar syndrome, jaundice is apparent at birth or in infancy. Severe unconjugated hyperbilirubinemia can lead to a condition called kernicterus, which is a form of brain damage caused by the accumulation of unconjugated bilirubin in the brain and nerve tissues. Babies with kernicterus are often extremely tired (lethargic) and may have weak muscle tone (hypotonia). These babies may experience episodes of increased muscle tone (hypertonia) and arching of their backs. Kernicterus can lead to other neurological problems, including involuntary writhing movements of the body (choreoathetosis), hearing problems, or intellectual disability. Crigler-Najjar syndrome is divided into two types. Type 1 (CN1) is very severe, and affected individuals can die in childhood due to kernicterus, although with proper treatment, they may survive longer. Type 2 (CN2) is less severe. People with CN2 are less likely to develop kernicterus, and most affected individuals survive into adulthood.
DiGeorge sequence
MedGen UID:
4297
Concept ID:
C0012236
Disease or Syndrome
Individuals with 22q11.2 deletion syndrome (22q11.2DS) have a range of findings including the following: Congenital heart disease (74% of individuals), particularly conotruncal malformations (tetralogy of Fallot, interrupted aortic arch, ventricular septal defect, and truncus arteriosus). Palatal abnormalities (69%), particularly velopharyngeal incompetence, submucosal cleft palate, bifid uvula, and cleft palate. Characteristic facial features (present in the majority of individuals of northern European heritage). Learning difficulties (70%-90%). An immune deficiency (regardless of the clinical presentation) (77%) . Additional findings include the following: Hypocalcemia (50%). Significant feeding and swallowing problems; constipation with or without structural gastrointestinal anomalies (intestinal malrotation, imperforate anus, and Hirschsprung disease). Renal anomalies (31%). Hearing loss (both conductive and sensorineural). Laryngotracheoesophageal anomalies. Growth hormone deficiency. Autoimmune disorders. Seizures (idiopathic or associated with hypocalcemia). CNS anomalies including tethered cord. Skeletal abnormalities (scoliosis with or without vertebral anomalies, clubbed feet, polydactyly, and craniosynostosis). Ophthalmologic abnormalities (strabismus, posterior embryotoxon, tortuous retinal vessels, scleracornea, and anophthalmia). Enamel hypoplasia. Malignancies (rare). Developmental delay (in particular delays in emergence of language), intellectual disability, and learning differences (non-verbal learning disability where the verbal IQ is significantly greater than the performance IQ) are common. Autism or autistic spectrum disorder is found in approximately 20% of children and psychiatric illness (specifically schizophrenia) is present in 25% of adults; however, attention deficit disorder, anxiety, perseveration, and difficulty with social interactions are also common.
Familial dysautonomia
MedGen UID:
41678
Concept ID:
C0013364
Congenital Abnormality
Familial dysautonomia (FD) affects the development and survival of sensory, sympathetic, and parasympathetic neurons. It is a debilitating disease present from birth. Neuronal degeneration progresses throughout life. Affected individuals have gastrointestinal dysfunction, vomiting crises, recurrent pneumonia, altered sensitivity to pain and temperature perception, and cardiovascular instability. About 40% of individuals have autonomic crises. Hypotonia contributes to delay in acquisition of motor milestones. Older individuals often have a broad-based and ataxic gait that deteriorates over time. Life expectancy is decreased.
Endocardial fibroelastosis
MedGen UID:
4041
Concept ID:
C0014117
Disease or Syndrome
A condition characterized by the thickening of ENDOCARDIUM due to proliferation of fibrous and elastic tissue, usually in the left ventricle leading to impaired cardiac function (CARDIOMYOPATHY, RESTRICTIVE). It is most commonly seen in young children and rarely in adults. It is often associated with congenital heart anomalies (HEART DEFECTS CONGENITAL;) INFECTION; or gene mutation. Defects in the tafazzin protein, encoded by TAZ gene, result in a form of autosomal dominant familial endocardial fibroelastosis.
Facial hemiatrophy
MedGen UID:
8761
Concept ID:
C0015458
Disease or Syndrome
A syndrome characterized by slowly progressive unilateral atrophy of facial subcutaneous fat, muscle tissue, skin, cartilage, and bone. The condition typically progresses over a period of 2-10 years and then stabilizes.
Progressive myositis ossificans
MedGen UID:
4698
Concept ID:
C0016037
Disease or Syndrome
Fibrodysplasia ossificans progressiva is a rare autosomal dominant disease with complete penetrance involving progressive ossification of skeletal muscle, fascia, tendons, and ligaments. FOP has a prevalence of approximately 1 in 2 million worldwide, and shows no geographic, ethnic, racial, or gender preference. Individuals with FOP appear normal at birth except for great toe abnormalities: the great toes are short, deviated, and monophalangic. Ossification occurs progressively over the course of a lifetime in an inevitable and unpredictable episodic manner, with most patients being confined to a wheelchair by the third decade of life and requiring lifelong care (summary by Petrie et al., 2009).
Fragile X syndrome
MedGen UID:
8912
Concept ID:
C0016667
Disease or Syndrome
FMR1-related disorders include fragile X syndrome, fragile X-associated tremor/ataxia syndrome (FXTAS), and FMR1-related primary ovarian insufficiency (POI). Fragile X syndrome occurs in individuals with an FMR1 full mutation or other loss-of-function mutation and is nearly always characterized by moderate intellectual disability in affected males and mild intellectual disability in affected females. Because FMR1 mutations are complex alterations involving non-classic gene-disrupting alterations (trinucleotide repeat expansion) and abnormal gene methylation, affected individuals occasionally have an atypical presentation with an IQ above 70, the traditional demarcation denoting intellectual disability (previously referred to as mental retardation). Males with an FMR1 full mutation accompanied by aberrant methylation may have a characteristic appearance (large head, long face, prominent forehead and chin, protruding ears), connective tissue findings (joint laxity), and large testes after puberty. Behavioral abnormalities, sometimes including autism spectrum disorder, are common. FXTAS occurs in males (and some females) who have an FMR1 premutation and is characterized by late-onset, progressive cerebellar ataxia and intention tremor. FMR1-related POI (age at cessation of menses <40 years) occurs in approximately 20% of females who have an FMR1 premutation.
Hereditary fructosuria
MedGen UID:
42105
Concept ID:
C0016751
Disease or Syndrome
Fructose intolerance becomes apparent in infancy at the time of weaning, when fructose or sucrose is added to the diet. Clinical features include recurrent vomiting, abdominal pain, and hypoglycemia that may be fatal. Long-term exposure to fructose can result in liver failure, renal tubulopathy, and growth retardation. Older patients who survive infancy develop a natural avoidance of sweets and fruits. Ali et al. (1998) provided a detailed review of the biochemical, genetic, and molecular basis of aldolase B deficiency in hereditary fructose intolerance.
Fructose-biphosphatase deficiency
MedGen UID:
42106
Concept ID:
C0016756
Disease or Syndrome
Fructose-1,6-bisphosphatase deficiency is an autosomal recessive disorder characterized by impaired gluconeogenesis. Patients present with hypoglycemia and metabolic acidosis on fasting and may have episodes of hyperventilation, apnea, hypoglycemia, and ketosis. Although the disorder may be lethal in the newborn period, proper treatment yields an excellent prognosis (Kikawa et al., 1997; Matsuura et al., 2002).
Fucosidosis
MedGen UID:
5288
Concept ID:
C0016788
Disease or Syndrome
Fucosidosis is an autosomal recessive lysosomal storage disease caused by defective alpha-L-fucosidase with accumulation of fucose in the tissues. Clinical features include angiokeratoma, progressive psychomotor retardation, neurologic signs, coarse facial features, and dysostosis multiplex. Fucosidosis has been classified into 2 major types. Type 1 is characterized by rapid psychomotor regression and severe neurologic deterioration beginning at about 6 months of age, elevated sweat sodium chloride, and death within the first decade of life. Type 2 is characterized by milder psychomotor retardation and neurologic signs, the development of angiokeratoma corporis diffusum, normal sweat salinity, and longer survival (Kousseff et al., 1976).
Glycogen storage disease, type II
MedGen UID:
5340
Concept ID:
C0017921
Congenital Abnormality
Glycogen storage disease type II (GSD II), or Pompe disease, is classified by age of onset, organ involvement, severity, and rate of progression. Classic infantile-onset Pompe disease may be apparent in utero but more often presents in the first two months of life with hypotonia, generalized muscle weakness, cardiomegaly and hypertrophic cardiomyopathy, feeding difficulties, failure to thrive, respiratory distress, and hearing loss. Without treatment by enzyme replacement therapy (ERT), classic infantile-onset Pompe disease commonly results in death in the first year of life from progressive left ventricular outflow obstruction. The non-classic variant of infantile-onset Pompe disease usually presents within the first year of life with motor delays and/or slowly progressive muscle weakness, typically resulting in death from ventilatory failure in early childhood. Cardiomegaly can be seen, but heart disease is not a major source of morbidity. Late-onset (i.e., childhood, juvenile, and adult-onset) Pompe disease is characterized by proximal muscle weakness and respiratory insufficiency; clinically significant cardiac involvement is uncommon in the late-onset form.
Pigmentary pallidal degeneration
MedGen UID:
6708
Concept ID:
C0018523
Disease or Syndrome
Pantothenate kinase-associated neurodegeneration (PKAN) is a form of neurodegeneration with brain iron accumulation, or NBIA (formerly called Hallervorden-Spatz syndrome). PKAN is characterized by progressive dystonia and basal ganglia iron deposition with onset that usually occurs before age ten years. Commonly associated features include dysarthria, rigidity, and pigmentary retinopathy. Approximately 25% of affected individuals have an 'atypical' presentation with later onset (age >10 years), prominent speech defects, psychiatric disturbances, and more gradual progression of disease.
Cowden syndrome
MedGen UID:
5420
Concept ID:
C0018553
Neoplastic Process
Cowden syndrome is a disorder characterized by multiple noncancerous, tumor-like growths called hamartomas and an increased risk of developing certain cancers. Almost everyone with Cowden syndrome develops hamartomas. These growths are most commonly found on the skin and mucous membranes (such as the lining of the mouth and nose), but they can also occur in the intestine and other parts of the body. The growth of hamartomas on the skin and mucous membranes typically becomes apparent by a person's late twenties. Cowden syndrome is associated with an increased risk of developing several types of cancer, particularly cancers of the breast, a gland in the lower neck called the thyroid, and the lining of the uterus (the endometrium). Other cancers that have been identified in people with Cowden syndrome include colorectal cancer, kidney cancer, and a form of skin cancer called melanoma. Compared with the general population, people with Cowden syndrome develop these cancers at younger ages, often beginning in their thirties or forties. Other diseases of the breast, thyroid, and endometrium are also common in Cowden syndrome. Additional signs and symptoms can include an enlarged head (macrocephaly) and a rare, noncancerous brain tumor called Lhermitte-Duclos disease. A small percentage of affected individuals have delayed development or intellectual disability. The features of Cowden syndrome overlap with those of another disorder called Bannayan-Riley-Ruvalcaba syndrome. People with Bannayan-Riley-Ruvalcaba syndrome also develop hamartomas and other noncancerous tumors. Both conditions can be caused by mutations in the PTEN gene. Some people with Cowden syndrome have had relatives diagnosed with Bannayan-Riley-Ruvalcaba syndrome, and other individuals have had the characteristic features of both conditions. Based on these similarities, researchers have proposed that Cowden syndrome and Bannayan-Riley-Ruvalcaba syndrome represent a spectrum of overlapping features known as PTEN hamartoma tumor syndrome instead of two distinct conditions. Some people have some of the characteristic features of Cowden syndrome, particularly the cancers associated with this condition, but do not meet the strict criteria for a diagnosis of Cowden syndrome. These individuals are often described as having Cowden-like syndrome.
Neutral 1 amino acid transport defect
MedGen UID:
6723
Concept ID:
C0018609
Disease or Syndrome
An autosomal recessive inherited metabolic disorder caused by mutations in the SLC6A19 gene. It is characterized by defective absorption of neutral amino acids. Signs and symptoms include skin eruptions reminiscent of pellagra, aminoaciduria, and cerebellar ataxia.
Hydrocephalus
MedGen UID:
9335
Concept ID:
C0020255
Disease or Syndrome
Autosomal recessive nonsyndromic hydrocephalus is characterized by onset in utero of enlarged ventricles due to a disturbance of cerebrospinal fluid accumulation. Affected individuals may have neurologic impairment (summary by Drielsma et al., 2012). Hydrocephalus can also be caused by Arnold-Chiari malformation, atresia of foramen of Magendie, stenosis of aqueduct of Sylvius (307000), toxoplasmosis, hydranencephaly, etc. Furthermore, it develops in infancy or childhood in achondroplasia (100800) and in Hurler disease (607014). Genetic Heterogeneity of Congenital Hydrocephalus See also autosomal recessive HYC2 (615219), caused by mutation in the MPDZ gene (603785) on chromosome 9p. An X-linked form (307000) is caused by mutation in the L1CAM gene on (308840) on chromosome Xq28.
Incontinentia pigmenti syndrome
MedGen UID:
7049
Concept ID:
C0021171
Disease or Syndrome
Incontinentia pigmenti (IP) is a disorder that affects the skin, hair, teeth, nails, eyes, and central nervous system. Characteristic skin lesions evolve through four stages: I. Blistering (birth to age ~4 months). II. Wart-like rash (for several months). III. Swirling macular hyperpigmentation (age ~6 months into adulthood) . IV. Linear hypopigmentation. Alopecia, hypodontia, abnormal tooth shape, and dystrophic nails are observed. Neovascularization of the retina, present in some individuals, predisposes to retinal detachment. Neurologic findings including cognitive delays/intellectual disability and learning disability are occasionally seen.
Hypomelanosis of Ito
MedGen UID:
5920
Concept ID:
C0022283
Disease or Syndrome
A neurocutaneous syndrome characterized by a bizarre, more or less symmetrical leukoderma with depigmented streaks, patches, and whorls, sometimes associated with hyperkeratosis follicularis. Associated disorders include seizures, psychomotor retardation, macrocephaly, and ophthalmological and other abnormalities.
Kearns Sayre syndrome
MedGen UID:
9618
Concept ID:
C0022541
Disease or Syndrome
A mitochondrial disorder featuring the triad of chronic progressive EXTERNAL OPHTHALMOPLEGIA, cardiomyopathy (CARDIOMYOPATHIES) with conduction block (HEART BLOCK), and RETINITIS PIGMENTOSA. Disease onset is in the first or second decade. Elevated CSF protein, sensorineural deafness, seizures, and pyramidal signs may also be present. Ragged-red fibers are found on muscle biopsy. (Adams et al., Principles of Neurology, 6th ed, p984)
Keratosis follicularis
MedGen UID:
5956
Concept ID:
C0022595
Disease or Syndrome
Darier-White disease, also known as keratosis follicularis, is an autosomal dominant skin disorder characterized by warty papules and plaques in seborrheic areas (central trunk, flexures, scalp, and forehead), palmoplantar pits, and distinctive nail abnormalities (Sakuntabhai et al., 1999). The prevalence of the disease had been estimated at 1 in 55,000. Onset is usually before the third decade, and penetrance is complete in adults, although expressivity is variable. Involvement may be severe, with widespread itchy malodorous crusted plaques, painful erosions, blistering, and mucosal lesions. Secondary infection is common. Sun, heat, and sweating exacerbate the disease. Darier disease never remits, but oral retinoids may reduce hyperkeratosis. Neuropsychiatric abnormalities, including mild mental retardation and epilepsy, have been described in association with Darier disease in a few families (Burge and Wilkinson, 1992); whether this is an association based on pleiotropism of the mutant gene or reflects coincidence is not clear. Histologic findings are (1) mild nonspecific perivascular infiltration in the dermis; (2) dermal villi protruding into the epidermis; (3) suprabasal detachment of the spinal layer leading to the formation of lacunae containing acantholytic cells; (4) in the more superficial epidermis, dyskeratotic round epidermal cells ('corps ronds'), the most distinctive feature; and (5) in the stratum corneum, 'grains' that resemble parakeratotic cells embedded in a hyperkeratotic horny layer. Electron microscopy reveals loss of desmosomal attachments, perinuclear aggregations of keratin filaments, and cytoplasmic vacuolization. Ultrastructural and immunologic studies suggest the disease results from an abnormality in the desmosome-keratin filament complex leading to a breakdown in cell adhesion.
Menkes kinky-hair syndrome
MedGen UID:
44030
Concept ID:
C0022716
Disease or Syndrome
Menkes disease, occipital horn syndrome (OHS), and ATP7A-related distal motor neuropathy (DMN) are disorders of copper transport caused by mutations in the copper-transporting ATPase gene (ATP7A). Infants with classic Menkes disease appear healthy until age two to three months, when loss of developmental milestones, hypotonia, seizures, and failure to thrive occur. The diagnosis is usually suspected when infants exhibit typical neurologic changes and concomitant characteristic changes of the hair (short, sparse, coarse, twisted, and often lightly pigmented). Temperature instability and hypoglycemia may be present in the neonatal period. Death usually occurs by age three years. Occipital horn syndrome is characterized by "occipital horns," distinctive wedge-shaped calcifications at the sites of attachment of the trapezius muscle and the sternocleidomastoid muscle to the occipital bone. Occipital horns may be clinically palpable or observed on skull radiographs. Individuals with OHS also have lax skin and joints, bladder diverticula, inguinal hernias, and vascular tortuosity. Intellect is normal or slightly reduced. ATP7A-related distal motor neuropathy, an adult-onset disorder resembling Charcot-Marie-Tooth disease, shares none of the clinical or biochemical abnormalities characteristic of Menkes disease or OHS.
Klippel Trenaunay syndrome
MedGen UID:
9646
Concept ID:
C0022739
Congenital Abnormality
Klippel-Trenaunay syndrome is a condition that affects the development of blood vessels, soft tissues, and bones. The disorder has three characteristic features: a red birthmark called a port-wine stain, abnormal overgrowth of soft tissues and bones, and vein malformations. Most people with Klippel-Trenaunay syndrome are born with a port-wine stain. This type of birthmark is caused by swelling of small blood vessels near the surface of the skin. Port-wine stains are typically flat and can vary from pale pink to deep maroon in color. In people with Klippel-Trenaunay syndrome, the port-wine stain usually covers part of one limb. The affected area may become lighter or darker with age. Occasionally, port-wine stains develop small red blisters that break open and bleed easily. Klippel-Trenaunay syndrome is also associated with overgrowth of bones and soft tissues beginning in infancy. Usually this abnormal growth is limited to one limb, most often one leg. However, overgrowth can also affect the arms or, rarely, the trunk. The abnormal growth can cause pain, a feeling of heaviness, and reduced movement in the affected area. If the overgrowth causes one leg to be longer than the other, it can also lead to problems with walking. Malformations of veins are the third major feature of Klippel-Trenaunay syndrome. These abnormalities include varicose veins, which are swollen and twisted veins near the surface of the skin that often cause pain. Varicose veins usually occur on the sides of the upper legs and calves. Veins deep in the limbs can also be abnormal in people with Klippel-Trenaunay syndrome. Malformations of deep veins increase the risk of a type of clot called a deep vein thrombosis (DVT). If a DVT travels through the bloodstream and lodges in the lungs, it can cause a life-threatening clot known as a pulmonary embolism (PE). Complications of Klippel-Trenaunay syndrome can include a type of skin infection called cellulitis, swelling caused by a buildup of fluid (lymphedema), and internal bleeding from abnormal blood vessels. Less commonly, this condition is also associated with fusion of certain fingers or toes (syndactyly) or the presence of extra digits (polydactyly).
Adult neuronal ceroid lipofuscinosis
MedGen UID:
7230
Concept ID:
C0022797
Disease or Syndrome
The neuronal ceroid-lipofuscinoses (NCLs) are a group of inherited, neurodegenerative, lysosomal storage disorders characterized by progressive intellectual and motor deterioration, seizures, and early death. Visual gvhmloss is a feature of most forms. Clinical phenotypes have been characterized traditionally according to the age of onset and order of appearance of clinical features into infantile, late-infantile, juvenile, adult, and Northern epilepsy (also known as progressive epilepsy with mental retardation [EPMR]). There is however genetic and allelic heterogeneity; a proposed new nomenclature and classification system has been developed to take into account both the responsible gene and the age at disease onset; for example, CLN1 disease, infantile onset and CLN1 disease, juvenile onset are both caused by mutations in PPT1 but with differing age of onset. The most prevalent NCLs are CLN3 disease, classic juvenile and CLN2 disease, classic late infantile (although prevalence varies by ethnicity and country of family origin): CLN2 disease, classic late infantile. The first symptoms typically appear between age two and four years, usually starting with epilepsy, followed by regression of developmental milestones, myoclonic ataxia, and pyramidal signs. Visual impairment typically appears at age four to six years and rapidly progresses to light /dark awareness only. Life expectancy ranges from age six years to early teenage. CLN3 disease, classic juvenile. Onset is usually between ages four and ten years. Rapidly progressing visual loss resulting in severe visual impairment within one to two years is often the first clinical sign. Epilepsy with generalized tonic-clonic seizures and/or complex-partial seizures typically appears around age ten years. Life expectancy ranges from the late teens to the 30s. Other forms of NCL may present with behavior changes, epilepsy, visual impairment, or slowing of developmental progress and then loss of skills. The course may be extremely variable. Some genotype-phenotype information is available.
Leigh's disease
MedGen UID:
44095
Concept ID:
C0023264
Disease or Syndrome
Leigh syndrome is an early-onset progressive neurodegenerative disorder with a characteristic neuropathology consisting of focal, bilateral lesions in one or more areas of the central nervous system, including the brainstem, thalamus, basal ganglia, cerebellum, and spinal cord. The lesions are areas of demyelination, gliosis, necrosis, spongiosis, or capillary proliferation. Clinical symptoms depend on which areas of the central nervous system are involved. The most common underlying cause is a defect in oxidative phosphorylation (Dahl, 1998). Leigh syndrome may be a feature of a deficiency of any of the mitochondrial respiratory chain complexes: complex I deficiency (252010), complex II deficiency (252011), complex III deficiency (124000), complex IV deficiency (cytochrome c oxidase; 220110), or complex V deficiency (604273).
Galactosylceramide beta-galactosidase deficiency
MedGen UID:
44131
Concept ID:
C0023521
Disease or Syndrome
Krabbe disease is characterized by infantile-onset progressive neurologic deterioration and death before age two years (85%-90% of individuals) or by onset between age one year and the fifth decade with slower disease progression (10%-15%). Children with the infantile form appear to be normal for the first few months of life but show extreme irritability, spasticity, and developmental delay before age six months; psychomotor regression progresses to a decerebrate state with no voluntary movement. The onset and progression in the late-onset forms can be quite variable. Individuals can be clinically normal until weakness, vision loss, and intellectual regression become evident. The onset of symptoms and clinical course can be variable even among siblings.
Metachromatic leukodystrophy
MedGen UID:
6071
Concept ID:
C0023522
Disease or Syndrome
Arylsulfatase A deficiency (also known as metachromatic leukodystrophy or MLD) is characterized by three clinical subtypes: late-infantile MLD (50%-60% of cases); juvenile MLD (20%-30% of cases); and adult MLD (15%-20% of cases). Age of onset within a family is usually similar. The disease course may be from three to ten or more years in the late-infantile form and up to 20 years or more in the juvenile and adult forms. Late-infantile MLD. Onset is between ages one and two years. Typical presenting findings include weakness, hypotonia, clumsiness, frequent falls, toe walking, and slurred speech. Later signs include inability to stand, difficulty with speech, deterioration of mental function, increased muscle tone, pain in the arms and legs, generalized or partial seizures, compromised vision and hearing, and peripheral neuropathy. In the final stages children have tonic spasms, decerebrate posturing, and general unawareness of their surroundings. Juvenile MLD. Onset is between age four years and sexual maturity (age 12-14 years). Initial manifestations include decline in school performance and emergence of behavioral problems, followed by clumsiness, gait problems, slurred speech, incontinence, and bizarre behaviors. Seizures may occur. Progression is similar to but slower than the late-infantile form. Adult MLD. Onset occurs after sexual maturity, sometimes not until the fourth or fifth decade. Initial signs can include problems in school or job performance, personality changes, alcohol or drug abuse, poor money management, and emotional lability; in others, neurologic symptoms (weakness and loss of coordination progressing to spasticity and incontinence) or seizures predominate initially. Peripheral neuropathy is common. Disease course is variable, with periods of stability interspersed with periods of decline, and may extend over two to three decades. The final stage is similar to that for the earlier-onset forms.
Lipid proteinosis
MedGen UID:
6112
Concept ID:
C0023795
Disease or Syndrome
Lipoid proteinosis of Urbach and Wiethe is a rare autosomal recessive disorder typified by generalized thickening of skin, mucosae, and certain viscera. Classic features include beaded eyelid papules and laryngeal infiltration leading to hoarseness. The disorder is clinically heterogeneous, with affected individuals displaying differing degrees of skin scarring and infiltration, variable signs of hoarseness and respiratory distress, and in some cases neurologic abnormalities such as temporal lobe epilepsy. Histologically, there is widespread deposition of hyaline (glycoprotein) material and disruption/reduplication of basement membrane (summary by Hamada et al., 2002 and Hamada et al., 2003).
Systemic lupus erythematosus
MedGen UID:
6146
Concept ID:
C0024141
Disease or Syndrome
Systemic lupus erythematosus (SLE) is a complex autoimmune disease characterized by production of autoantibodies against nuclear, cytoplasmic, and cell surface molecules that transcend organ-specific boundaries. Tissue deposition of antibodies or immune complexes induces inflammation and subsequent injury of multiple organs and finally results in clinical manifestations of SLE, including glomerulonephritis, dermatitis, thrombosis, vasculitis, seizures, and arthritis. Evidence strongly suggests the involvement of genetic components in SLE susceptibility (summary by Oishi et al., 2008). Genetic Heterogeneity of Systemic Lupus Erythematosus An autosomal recessive form of systemic lupus erythematosus (SLEB16; 614420) is caused by mutation in the DNASE1L3 gene (602244) on chromosome 3p14.3. See MAPPING and MOLECULAR GENETICS sections for a discussion of genetic heterogeneity of susceptibility to SLE.
Intestinal lymphangiectasis
MedGen UID:
9828
Concept ID:
C0024215
Disease or Syndrome
Dilatation of the intestinal lymphatic system usually caused by an obstruction in the intestinal wall. It may be congenital or acquired and is characterized by DIARRHEA; HYPOPROTEINEMIA; peripheral and/or abdominal EDEMA; and PROTEIN-LOSING ENTEROPATHIES.
Maple syrup urine disease
MedGen UID:
6217
Concept ID:
C0024776
Disease or Syndrome
Maple syrup urine disease (MSUD) is classified as classic or intermediate. Twelve hours after birth, untreated neonates with classic MSUD have a maple syrup odor in cerumen; by 12-24 hours, elevated plasma concentrations of branched-chain amino acids (BCAAs) (leucine, isoleucine, and valine) and allo-isoleucine, as well as a generalized disturbance of plasma amino acid concentration ratios; by age two to three days, ketonuria, irritability, and poor feeding; by age four to five days, deepening encephalopathy manifesting as lethargy, intermittent apnea, opisthotonus, and stereotyped movements such as "fencing" and "bicycling." By age seven to ten days, coma and central respiratory failure may supervene. Individuals with intermediate MSUD have partial BCKAD enzyme deficiency that only manifests intermittently or responds to dietary thiamine therapy; these individuals can experience severe metabolic intoxication and encephalopathy during sufficient catabolic stress.
Mohr syndrome
MedGen UID:
10077
Concept ID:
C0026363
Disease or Syndrome
Oral-facial-digital syndrome is actually a group of related conditions that affect the development of the oral cavity (the mouth and teeth), facial features, and digits (fingers and toes). Researchers have identified at least 13 potential forms of oral-facial-digital syndrome. The different types are classified by their patterns of signs and symptoms. However, the features of the various types overlap significantly, and some types are not well defined. The classification system for oral-facial-digital syndrome continues to evolve as researchers find more affected individuals and learn more about this disorder. The signs and symptoms of oral-facial-digital syndrome vary widely. However, most forms of this disorder involve problems with development of the oral cavity, facial features, and digits. Most forms are also associated with brain abnormalities and some degree of intellectual disability. Abnormalities of the oral cavity that occur in many types of oral-facial-digital syndrome include a split (cleft) in the tongue, a tongue with an unusual lobed shape, and the growth of noncancerous tumors or nodules on the tongue. Affected individuals may also have extra, missing, or defective teeth. Another common feature is an opening in the roof of the mouth (a cleft palate). Some people with oral-facial-digital syndrome have bands of extra tissue (called hyperplastic frenula) that abnormally attach the lip to the gums. Distinctive facial features often associated with oral-facial-digital syndrome include a split in the lip (a cleft lip); a wide nose with a broad, flat nasal bridge; and widely spaced eyes (hypertelorism). Abnormalities of the digits can affect both the fingers and the toes in people with oral-facial-digital syndrome. These abnormalities include fusion of certain fingers or toes (syndactyly), digits that are shorter than usual (brachydactyly), or digits that are unusually curved (clinodactyly). The presence of extra digits (polydactyly) is also seen in most forms of oral-facial-digital syndrome. Other features occur in only one or a few types of oral-facial digital syndrome. These features help distinguish the different forms of the disorder. For example, the most common form of oral-facial-digital syndrome, type I, is associated with polycystic kidney disease. This kidney disease is characterized by the growth of fluid-filled sacs (cysts) that interfere with the kidneys' ability to filter waste products from the blood. Other forms of oral-facial-digital syndrome are characterized by neurological problems, particular changes in the structure of the brain, bone abnormalities, vision loss, and heart defects.
Mucopolysaccharidosis, MPS-II
MedGen UID:
7734
Concept ID:
C0026705
Disease or Syndrome
Mucopolysaccharidosis type II (MPS II; also known as Hunter syndrome) is an X-linked multisystem disorder characterized by glycosaminoglycans (GAG) accumulation. The vast majority of affected individuals are male; on rare occasion heterozygous females manifest findings. Age of onset, disease severity, and rate of progression vary significantly among affected males. In those with early progressive disease, CNS involvement (manifest primarily by progressive cognitive deterioration), progressive airway disease, and cardiac disease usually result in death in the first or second decade of life. In those with slowly progressive disease, the CNS is not (or is minimally) affected, although the effect of GAG accumulation on other organ systems may be early progressive to the same degree as in those who have progressive cognitive decline. Survival into the early adult years with normal intelligence is common in the slowly progressing form of the disease. Additional findings in both forms of MPS II include: short stature; macrocephaly with or without communicating hydrocephalus; macroglossia; hoarse voice; conductive and sensorineural hearing loss; hepato-splenomegaly; dysostosis multiplex; spinal stenosis; and carpal tunnel syndrome.
Neurofibromatosis, type 1
MedGen UID:
18013
Concept ID:
C0027831
Neoplastic Process
Neurofibromatosis 1 (NF1) is characterized by multiple café-au-lait spots, axillary and inguinal freckling, multiple cutaneous neurofibromas, and iris Lisch nodules. Learning disabilities are present in at least 50% of individuals with NF1. Less common but potentially more serious manifestations include plexiform neurofibromas, optic nerve and other central nervous system gliomas, malignant peripheral nerve sheath tumors, scoliosis, tibial dysplasia, and vasculopathy.
Lowe syndrome
MedGen UID:
18145
Concept ID:
C0028860
Disease or Syndrome
Lowe syndrome (oculocerebrorenal syndrome) is characterized by involvement of the eyes, central nervous system, and kidneys. Dense congenital cataracts are found in all affected boys and infantile glaucoma in approximately 50%. All boys have impaired vision; corrected acuity is rarely better than 20/100. Generalized hypotonia is noted at birth and is of central (brain) origin. Deep tendon reflexes are usually absent. Hypotonia may slowly improve with age, but normal motor tone and strength are never achieved. Motor milestones are delayed. Almost all affected males have some degree of intellectual disability; 10%-25% function in the low-normal or borderline range, approximately 25% in the mild-to-moderate range, and 50%-65% in the severe-to-profound range of intellectual disability. Affected males have varying degrees of proximal renal tubular dysfunction of the Fanconi type, including bicarbonate wasting and renal tubular acidosis, phosphaturia with hypophosphatemia and renal rickets, aminoaciduria, low molecular-weight (LMW) proteinuria, sodium and potassium wasting, and polyuria. Fanconi syndrome is usually not clinically apparent in the first few months of life, but symptoms may appear by age six to 12 months. Glomerulosclerosis associated with chronic tubular injury usually results in slowly progressive chronic renal failure and end-stage renal disease after age ten to 20 years.
Phenylketonuria
MedGen UID:
19244
Concept ID:
C0031485
Disease or Syndrome
Phenylalanine hydroxylase (PAH) deficiency results in intolerance to the dietary intake of the essential amino acid phenylalanine and produces a spectrum of disorders including phenylketonuria (PKU), non-PKU hyperphenylalaninemia (non-PKU HPA), and variant PKU. Classic PKU is caused by a complete or near-complete deficiency of phenylalanine hydroxylase activity; without dietary restriction of phenylalanine, most children with PKU develop profound and irreversible intellectual disability. Non-PKU HPA is associated with a much lower risk of impaired cognitive development in the absence of treatment.
Prader-Willi syndrome
MedGen UID:
46057
Concept ID:
C0032897
Congenital Abnormality
Prader-Willi (PWS) syndrome is characterized by severe hypotonia and feeding difficulties in early infancy, followed in later infancy or early childhood by excessive eating and gradual development of morbid obesity (unless eating is externally controlled). Motor milestones and language development are delayed. All individuals have some degree of cognitive impairment. A distinctive behavioral phenotype (with temper tantrums, stubbornness, manipulative behavior, and obsessive-compulsive characteristics) is common. Hypogonadism is present in both males and females and manifests as genital hypoplasia, incomplete pubertal development, and, in most, infertility. Short stature is common; characteristic facial features, strabismus, and scoliosis are often present, and non-insulin-dependent diabetes mellitus often occurs in obese individuals.
Preeclampsia/eclampsia 1
MedGen UID:
18608
Concept ID:
C0032914
Pathologic Function
Preeclampsia, which along with chronic hypertension and gestational hypertension comprise the hypertensive disorders of pregnancy, is characterized by new hypertension (blood pressure 140/90 or greater) presenting after 20 weeks' gestation with clinically relevant proteinuria. Preeclampsia is 1 of the top 4 causes of maternal mortality and morbidity worldwide (summary by Payne et al., 2011). Preeclampsia is otherwise known as gestational proteinuric hypertension (Davey and MacGillivray, 1988). A high proportion of patients with preeclampsia have glomerular endotheliosis, the unique histopathologic feature of the condition (Fisher et al., 1981). A distinct form of severe preeclampsia is characterized by hemolysis, elevated liver enzymes, and low platlets (HELLP syndrome) (Brown et al., 2000). Genetic Heterogeneity of Preeclampsia/Eclampsia Susceptibility loci for preeclampsia/eclampsia include PEE1 on chromosome 2p13, PEE2 (609402) on chromosome 2p25, and PEE3 (609403) on chromosome 9p13. PEE4 (609404) is caused by mutation in the STOX1 gene (609397) on chromosome 10q22. PEE5 (614595) is caused by mutation in the CORIN gene (605236) on chromosome 4p12. An association with PEE has been found with the EPHX1 gene (132810) on chromosome 1q.
Pseudohypoparathyroidism type 1A
MedGen UID:
46178
Concept ID:
C0033806
Disease or Syndrome
Pseudohypoparathyroidism is a term applied to a heterogeneous group of disorders whose common feature is end-organ resistance to parathyroid hormone (PTH; 168450). In addition to PTH resistance, PHP Ia is characterized by resistance to other hormones, including thyroid-stimulating hormone (TSH; see TSHB, 188540) and gonadotropins. PHP Ia is associated with a constellation of clinical features referred to as Albright hereditary osteodystrophy (AHO), which includes short stature, obesity, round facies, subcutaneous ossifications, brachydactyly, and other skeletal anomalies. Some patients have mental retardation (Mantovani and Spada, 2006). In contrast, pseudopseudohypoparathyroidism (PPHP; 612463) is characterized by the physical findings of AHO but without hormone resistance (Kinard et al., 1979; Fitch, 1982; Mantovani and Spada, 2006). PHP1A occurs only after maternal inheritance of the molecular defect, whereas PPHP occurs only after paternal inheritance of the molecular defect (Davies and Hughes, 1993; Wilson et al., 1994). This is an example of imprinting, with differential gene expression depending on the parent of origin of the allele. See INHERITANCE and PATHOGENESIS sections.
Pyruvate carboxylase deficiency
MedGen UID:
18801
Concept ID:
C0034341
Disease or Syndrome
Pyruvate carboxylase (PC) deficiency is characterized in most affected individuals by failure to thrive, developmental delay, recurrent seizures, and metabolic acidosis. Three clinical types are recognized: type A (infantile form), in which most affected children die in infancy or early childhood; type B (severe neonatal form), in which affected infants have hepatomegaly, pyramidal tract signs, and abnormal movement and die within the first three months of life; and type C (intermittent/benign form), in which affected individuals have normal or mildly delayed neurologic development and episodic metabolic acidosis.
Pyruvate dehydrogenase complex deficiency
MedGen UID:
19610
Concept ID:
C0034345
Disease or Syndrome
Genetic defects in the pyruvate dehydrogenase complex are one of the most common causes of primary lactic acidosis in children. Most cases are caused by mutation in the E1-alpha subunit gene on the X chromosome. X-linked PDH deficiency is one of the few X-linked diseases in which a high proportion of heterozygous females manifest severe symptoms. The clinical spectrum of PDH deficiency is broad, ranging from fatal lactic acidosis in the newborn to chronic neurologic dysfunction with structural abnormalities in the central nervous system without systemic acidosis (Robinson et al., 1987; Brown et al., 1994). Genetic Heterogeneity of Pyruvate Dehydrogenase Complex Deficiency PDH deficiency can also be caused by mutation in other subunits of the PDH complex, including a form (PDHXD; 245349) caused by mutation in the component X gene (PDHX; 608769) on chromosome 11p; a form (PDHBD; 614111) caused by mutation in the PDHB gene (179060) on chromosome 3p; a form (PDHDD; 245348) caused by mutation in the DLAT gene (608770) on chromosome 11q; a form (PDHPD; 608782) caused by mutation in the PDP1 gene (605993) on chromosome 8q22; and a form (PDHLD; 614462) caused by mutation in the LIAS gene (607031) on chromosome 4p14.
Rett's disorder
MedGen UID:
48441
Concept ID:
C0035372
Disease or Syndrome
MECP2-related disorders in females include classic Rett syndrome, variant Rett syndrome, and mild learning disabilities. A pathogenic MECP2 variant in a male is presumed to most often be lethal; phenotypes in rare surviving males are primarily severe neonatal encephalopathy and manic-depressive psychosis, pyramidal signs, Parkinsonian, and macro-orchidism (PPM-X syndrome). Classic Rett syndrome, a progressive neurodevelopmental disorder primarily affecting girls, is characterized by apparently normal psychomotor development during the first six to 18 months of life, followed by a short period of developmental stagnation, then rapid regression in language and motor skills, followed by long-term stability. During the phase of rapid regression, repetitive, stereotypic hand movements replace purposeful hand use. Additional findings include fits of screaming and inconsolable crying, autistic features, panic-like attacks, bruxism, episodic apnea and/or hyperpnea, gait ataxia and apraxia, tremors, seizures, and acquired microcephaly. Atypical Rett syndrome is observed increasingly as MECP2 variants are identified in individuals previously diagnosed with: clinically suspected but molecularly unconfirmed Angelman syndrome; intellectual disability with spasticity or tremor; mild learning disability; or (rarely) autism. Severe neonatal encephalopathy resulting in death before age two years is the most common phenotype observed in affected males.
Rubinstein-Taybi syndrome
MedGen UID:
48517
Concept ID:
C0035934
Disease or Syndrome
Rubinstein-Taybi syndrome (RSTS) is characterized by distinctive facial features, broad and often angulated thumbs and great toes, short stature, and moderate to severe intellectual disability. The characteristic craniofacial features are downslanted palpebral fissures, low hanging columella, high palate, grimacing smile, and talon cusps. Prenatal growth is often normal; however, height, weight, and head circumference percentiles rapidly drop in the first few months of life. Obesity may occur in childhood or adolescence. IQ scores range from 25 to 79; average IQ is between 36 and 51. Other variable findings are coloboma, cataract, congenital heart defects, renal abnormalities, and cryptorchidism.
Sandhoff disease
MedGen UID:
11313
Concept ID:
C0036161
Disease or Syndrome
Sandhoff disease is a progressive neurodegenerative disorder characterized by an accumulation of GM2 gangliosides, particularly in neurons, and is clinically indistinguishable from Tay-Sachs disease (272800).
Sjögren-Larsson syndrome
MedGen UID:
11443
Concept ID:
C0037231
Disease or Syndrome
Sjogren-Larsson syndrome is an autosomal recessive, early childhood-onset disorder characterized by ichthyosis, mental retardation, spastic paraparesis, macular dystrophy, and leukoencephalopathy. It is caused by deficiency of fatty aldehyde dehydrogenase (summary by Lossos et al., 2006).
Sturge-Weber syndrome
MedGen UID:
21361
Concept ID:
C0038505
Congenital Abnormality
Sturge-Weber syndrome is characterized by an intracranial vascular anomaly, leptomeningeal angiomatosis, most often involving the occipital and posterior parietal lobes. The most common symptoms and signs are facial cutaneous vascular malformations (port-wine stains), seizures, and glaucoma. Stasis results in ischemia underlying the leptomeningeal angiomatosis, leading to calcification and laminar cortical necrosis. The clinical course is highly variable and some children experience intractable seizures, mental retardation, and recurrent stroke-like episodes (review by Thomas-Sohl et al., 2004).
Takayasu arteritis
MedGen UID:
21458
Concept ID:
C0039263
Disease or Syndrome
A large vessel vasculitis affecting the aorta and its branches. It usually affects young females. It causes vascular obstruction, resulting in asymmetric pulses.
Tay-Sachs disease
MedGen UID:
11713
Concept ID:
C0039373
Disease or Syndrome
Hexosaminidase A deficiency results in a group of neurodegenerative disorders caused by intralysosomal storage of the specific glycosphingolipid, GM2 ganglioside. The prototype hexosaminidase A deficiency is Tay-Sachs disease, also known as the acute infantile variant. Tay-Sachs disease is characterized by progressive weakness, loss of motor skills, decreased attentiveness, and increased startle response beginning between ages three and six months with progressive evidence of neurodegeneration including: seizures, blindness, spasticity, eventual total incapacitation, and death, usually before age four years. The juvenile (subacute), chronic, and adult-onset variants of hexosaminidase A deficiency have later onsets, slower progression, and more variable neurologic findings, including: progressive dystonia, spinocerebellar degeneration, motor neuron disease, and, in some individuals with adult-onset disease, a bipolar form of psychosis.
Osler hemorrhagic telangiectasia syndrome
MedGen UID:
52657
Concept ID:
C0039445
Disease or Syndrome
Hereditary hemorrhagic telangiectasia (HHT) is characterized by the presence of multiple arteriovenous malformations (AVMs) that lack intervening capillaries and result in direct connections between arteries and veins. Although HHT is a developmental disorder and infants are occasionally severely affected, in most people the features are age-dependent and the diagnosis not suspected until adolescence or later. Small AVMs (or telangiectases) close to the surface of the skin and mucous membranes often rupture and bleed after slight trauma. The most common clinical manifestation is spontaneous and recurrent nosebleeds (epistaxis) beginning on average at age 12 years. Approximately 25% of individuals with HHT have GI bleeding, which most commonly begins after age 50 years. Large AVMs often cause symptoms when they occur in the brain, liver, or lungs; complications from bleeding or shunting may be sudden and catastrophic.
Wegener's granulomatosis
MedGen UID:
12144
Concept ID:
C0043092
Disease or Syndrome
Wegener granulomatosis (WG) is a systemic disease with a complex genetic background. It is characterized by necrotizing granulomatous inflammation of the upper and lower respiratory tract, glomerulonephritis, vasculitis, and the presence of antineutrophil cytoplasmatic autoantibodies (ANCAs) in patient sera. These ANCAs are antibodies to a defined target antigen, proteinase-3 (PR3, PRTN3; 177020), that is present within primary azurophil granules of neutrophils (PMNs) and lysozymes of monocytes. On cytokine priming of PMNs, PR3 translocates to the cell surface, where PR3-ANCAs can interact with their antigens and activate PMNs. PMNs from patients with active WG express PR3 on their surface, produce respiratory burst, and release proteolytic enzymes after activation with PR3-ANCAs. The consequence is a self-sustaining inflammatory process (Jagiello et al., 2004).
Diabetes mellitus AND insipidus with optic atrophy AND deafness
MedGen UID:
21923
Concept ID:
C0043207
Disease or Syndrome
WFS1-related disorders range from Wolfram syndrome (WFS) to WFS1-related low-frequency sensory hearing loss (also known as DFNA6/14/38 low-frequency sensorineural hearing loss [LFSNHL]). WFS is a progressive neurodegenerative disorder characterized by onset of diabetes mellitus and optic atrophy before age 16 years, and typically associated with sensorineural hearing loss, progressive neurologic abnormalities (cerebellar ataxia, peripheral neuropathy, dementia, psychiatric illness, and urinary tract atony), and other endocrine abnormalities. Median age at death is 30 years. WFS-like disease is characterized by sensorineural hearing loss, diabetes mellitus, psychiatric illness, and variable optic atrophy. WFS1-related LFSNHL is characterized by congenital, nonsyndromic, slowly progressive, low-frequency (<2000 Hz) sensorineural hearing loss.
Zellweger syndrome
MedGen UID:
21958
Concept ID:
C0043459
Congenital Abnormality
Peroxisome biogenesis disorders, Zellweger syndrome spectrum (PBD, ZSS) is a continuum of three phenotypes — Zellweger syndrome (ZS), the most severe; neonatal adrenoleukodystrophy (NALD); and infantile Refsum disease (IRD), the least severe — that were originally described before the biochemical and molecular bases of these disorders had been fully determined. Individuals with PBD, ZSS usually come to clinical attention in the newborn period or later in childhood. In the newborn period, affected children are hypotonic, feed poorly, and have distinctive facies, seizures, and liver cysts with hepatic dysfunction. Bony stippling (chondrodysplasia punctata) of the patella(e) and other long bones may occur. Infants with ZS are significantly impaired and typically die during the first year of life, usually having made no developmental progress. Older children have retinal dystrophy, sensorineural hearing loss, developmental delay with hypotonia, and liver dysfunction. The clinical courses of NALD and IRD are variable and may include developmental delays, hearing loss, vision impairment, liver dysfunction, episodes of hemorrhage, and intracranial bleeding. While some children can be very hypotonic, others learn to walk and talk. The condition is often slowly progressive.
Holoprosencephaly sequence
MedGen UID:
38214
Concept ID:
C0079541
Congenital Abnormality
Holoprosencephaly (HPE) is a structural anomaly of the brain in which there is failed or incomplete separation of the forebrain early in gestation. Classic HPE encompasses a continuum of brain malformations including (in order of decreasing severity): alobar, semilobar, lobar, and middle interhemispheric variant (MIHV) type HPE; a septopreoptic type has also been described. Other CNS abnormalities not specific to HPE may also occur. HPE is accompanied by a spectrum of characteristic craniofacial anomalies in approximately 80% of individuals with HPE. Developmental delay is present in virtually all individuals with the HPE spectrum of CNS anomalies. Seizures and pituitary dysfunction are common. Most affected fetuses do not survive; severely affected children typically do not survive beyond early infancy, while a significant proportion of more mildly affected children survive past 12 months. Mildly manifesting individuals without appreciable brain anomalies on conventional neuroimaging may be described as having “microform” HPE.
X-linked ichthyosis with steryl-sulfatase deficiency
MedGen UID:
86937
Concept ID:
C0079588
Disease or Syndrome
Ichthyosis is a genetically heterogeneous disorder of the skin. See, e.g., autosomal dominant ichthyosis vulgaris (146700), which is caused by mutations in the filaggrin gene (FLG; 135940). Ichthyosis can also be observed in multiple sulfatase deficiency (272200) (Shapiro, 1977). X-linked ichthyosis is fundamentally the same disorder as placental steroid sulfatase deficiency, which is often first noted in the pregnant mother of affected males by decreased estrogen or delayed progression of parturition (Alperin and Shapiro, 1997). This is thus an example of affinity ('lumping') of phenotypes thought previously to be separate, the opposite of genetic heterogeneity. Schnyder (1970) gave a useful classification of the inherited ichthyoses. Hernandez-Martin et al. (1999) provided a comprehensive review of X-linked ichthyosis. They pointed out that among all genetic disorders X-linked ichthyosis shows one of the highest ratios of chromosomal deletions; complete deletion has been found in up to 90% of patients.
Proteus syndrome
MedGen UID:
39008
Concept ID:
C0085261
Neoplastic Process
Proteus syndrome is characterized by progressive, segmental or patchy overgrowth of diverse tissues of all germ layers, most commonly affecting the skeleton, skin, and adipose and central nervous systems. In most individuals Proteus syndrome has minimal or no manifestations at birth, develops and progresses rapidly beginning in the toddler period, and relentlessly progresses through childhood, causing severe overgrowth and disfigurement. It is associated with a range of tumors, pulmonary complications, and a striking predisposition to deep vein thrombosis and pulmonary embolism.
Polyglandular autoimmune syndrome, type 2
MedGen UID:
39126
Concept ID:
C0085860
Disease or Syndrome
Autoimmune polyendocrine syndrome type II (APS2), or Schmidt syndrome, is characterized by the presence of autoimmune Addison disease in association with either autoimmune thyroid disease or type I diabetes mellitus, or both. Chronic candidiasis is not present. APS2 may occur at any age and in both sexes, but is most common in middle-aged females and is very rare in childhood (summary by Betterle et al., 2004). See 240300 for a phenotypic description of autoimmune polyendocrine syndrome type I (APS1).
Mucopolysaccharidosis, MPS-III-A
MedGen UID:
39264
Concept ID:
C0086647
Disease or Syndrome
The Sanfilippo syndrome, or mucopolysaccharidosis III, is an autosomal recessive lysosomal storage disease due to impaired degradation of heparan sulfate (Esposito et al., 2000). The disorder is characterized by severe central nervous system degeneration, but only mild somatic disease. Onset of clinical features usually occurs between 2 and 6 years; severe neurologic degeneration occurs in most patients between 6 and 10 years of age, and death occurs typically during the second or third decade of life. Type A has been reported (van de Kamp et al., 1981) to be the most severe, with earlier onset and rapid progression of symptoms and shorter survival. Genetic Heterogeneity of Mucopolysaccharidosis Type III MPS III includes 4 types, each due to the deficiency of a different enzyme: heparan N-sulfatase (type A); alpha-N-acetylglucosaminidase (type B; 252920); acetyl CoA:alpha-glucosaminide acetyltransferase (type C; 252930); and N-acetylglucosamine 6-sulfatase (type D; 252940).
Mucopolysaccharidosis, MPS-III-B
MedGen UID:
88601
Concept ID:
C0086648
Disease or Syndrome
Sanfilippo syndrome B is an autosomal recessive lysosomal storage disorder characterized by the accumulation of heparan sulfate. Clinically, patients have progressive neurodegeneration, behavioral problems, mild skeletal changes, and shortened life span. The clinical severity ranges from mild to severe (Chinen et al., 2005). For a phenotypic description and a discussion of genetic heterogeneity of Sanfilippo syndrome, or mucopolysaccharidosis III, see MPS IIIA (252900).
Mucopolysaccharidosis, MPS-III-C
MedGen UID:
39477
Concept ID:
C0086649
Disease or Syndrome
Sanfilippo syndrome comprises several forms of lysosomal storage diseases due to impaired degradation of heparan sulfate. The deficient enzyme in Sanfilippo syndrome C, or MPS IIIC, is an acetyltransferase that catalyzes the conversion of alpha-glucosaminide residues to N-acetylglucosaminide in the presence of acetyl-CoA. For a general phenotypic description and a discussion of genetic heterogeneity of Sanfilippo syndrome, see MPS IIIA (252900).
Mucopolysaccharidosis, MPS-III-D
MedGen UID:
88602
Concept ID:
C0086650
Disease or Syndrome
The mucopolysaccharidoses are a family of lysosomal storage diseases caused by deficiencies of enzymes required for the catabolism of glycosaminoglycans. The defects result in accumulation of excessive intralysosomal glycosoaminoglycans (mucopolysaccharides) in various tissues, causing distended lysosomes to accumulate in the cell and interfere with cell function. Multiple types have been described (Mok et al., 2003).
Cyclical vomiting syndrome
MedGen UID:
57509
Concept ID:
C0152164
Disease or Syndrome
Cyclic vomiting syndrome is a disorder that causes recurrent episodes of nausea, vomiting, and tiredness (lethargy). This condition is diagnosed most often in young children, but it can affect people of any age. The episodes of nausea, vomiting, and lethargy last anywhere from an hour to 10 days. An affected person may vomit several times per hour, potentially leading to a dangerous loss of fluids (dehydration). Additional symptoms can include unusually pale skin (pallor), abdominal pain, diarrhea, headache, fever, and an increased sensitivity to light (photophobia) or to sound (phonophobia). In most affected people, the signs and symptoms of each attack are quite similar. These attacks can be debilitating, making it difficult for an affected person to go to work or school. Episodes of nausea, vomiting, and lethargy can occur regularly or apparently at random, or can be triggered by a variety of factors. The most common triggers are emotional excitement and infections. Other triggers can include periods without eating (fasting), temperature extremes, lack of sleep, overexertion, allergies, ingesting certain foods or alcohol, and menstruation. If the condition is not treated, episodes usually occur four to 12 times per year. Between attacks, vomiting is absent, and nausea is either absent or much reduced. However, many affected people experience other symptoms during and between episodes, including pain, lethargy, digestive disorders such as gastroesophageal reflux and irritable bowel syndrome, and fainting spells (syncope). People with cyclic vomiting syndrome are also more likely than people without the disorder to experience depression, anxiety, and panic disorder. It is unclear whether these health conditions are directly related to nausea and vomiting. Cyclic vomiting syndrome is often considered to be a variant of migraines, which are severe headaches often associated with pain, nausea, vomiting, and extreme sensitivity to light and sound. Cyclic vomiting syndrome is likely the same as or closely related to a condition called abdominal migraine, which is characterized by attacks of stomach pain and cramping. Attacks of nausea, vomiting, or abdominal pain in childhood may be replaced by migraine headaches as an affected person gets older. Many people with cyclic vomiting syndrome or abdominal migraine have a family history of migraines. Most people with cyclic vomiting syndrome have normal intelligence, although some affected people have developmental delay or intellectual disability. Autism spectrum disorders, which affect communication and social interaction, have also been associated with cyclic vomiting syndrome. Additionally, muscle weakness (myopathy) and seizures are possible. People with any of these additional features are said to have cyclic vomiting syndrome plus.
Adrenoleukodystrophy
MedGen UID:
57667
Concept ID:
C0162309
Disease or Syndrome
X-linked adrenoleukodystrophy (X-ALD) affects the nervous system white matter and the adrenal cortex. Three main phenotypes are seen in affected males: The childhood cerebral form manifests most commonly between ages four and eight years. It initially resembles attention deficit disorder or hyperactivity; progressive impairment of cognition, behavior, vision, hearing, and motor function follow the initial symptoms and often lead to total disability within two years. Adrenomyeloneuropathy (AMN) manifests most commonly in the late twenties as progressive paraparesis, sphincter disturbances, sexual dysfunction, and often, impaired adrenocortical function; all symptoms are progressive over decades. "Addison disease only" presents with primary adrenocortical insufficiency between age two years and adulthood and most commonly by age 7.5 years, without evidence of neurologic abnormality; however, some degree of neurologic disability (most commonly AMN) usually develops later. Approximately 20% of females who are carriers develop neurologic manifestations that resemble AMN but have later onset (age =35 years) and milder disease than do affected males.
Acute intermittent porphyria
MedGen UID:
56452
Concept ID:
C0162565
Disease or Syndrome
Acute intermittent porphyria (referred to as AIP in this GeneReview) results from half-normal activity of the enzyme hydroxymethylbilane synthase (HMBS). It is characterized clinically by life-threatening acute neurovisceral attacks of severe abdominal pain without peritoneal signs, often accompanied by nausea, vomiting, tachycardia, and hypertension. Attacks may be complicated by neurologic findings (mental changes, convulsions, and peripheral neuropathy that may progress to respiratory paralysis), and hyponatremia. Acute attacks, which may be provoked by certain drugs, alcoholic beverages, endocrine factors, calorie restriction, stress, and infections, usually resolve within two weeks. Most individuals with AIP have one or a few attacks; about 5% (mainly women) have recurrent attacks (defined as >4 attacks/year) that may persist for years. Other long-term complications are chronic renal failure, hepatocellular carcinoma (HCC), and hypertension. Attacks, which are very rare before puberty, are more common in women than men. All individuals with a genetic change in the gene HMBS that predisposes to AIP are at risk of developing acute attacks; however, most never have symptoms and are said to have latent (or presymptomatic) AIP.
Angelman syndrome
MedGen UID:
58144
Concept ID:
C0162635
Disease or Syndrome
Angelman syndrome (AS) is characterized by severe developmental delay or intellectual disability, severe speech impairment, gait ataxia and/or tremulousness of the limbs, and a unique behavior with an inappropriate happy demeanor that includes frequent laughing, smiling, and excitability. Microcephaly and seizures are also common. Developmental delays are first noted at around age six months; however, the unique clinical features of AS do not become manifest until after age one year, and it can take several years before the correct clinical diagnosis is obvious.
Myoclonus with epilepsy with ragged red fibers
MedGen UID:
56486
Concept ID:
C0162672
Disease or Syndrome
A very rare mitochondrial abnormality characterized by myoclonic epilepsy and the microscopic finding of ragged-red fibers in muscle tissues.
Citrullinemia type I
MedGen UID:
104491
Concept ID:
C0175683
Disease or Syndrome
Citrullinemia type I (CTLN1) presents as a clinical spectrum that includes an acute neonatal form (the "classic" form), a milder late-onset form, a form without symptoms or hyperammonemia, and a form in which women have onset of severe symptoms during pregnancy or post partum. Distinction between the clinical forms is based on clinical findings and is not clear-cut. Infants with the acute neonatal form appear normal at birth. Shortly thereafter, they develop hyperammonemia and become progressively lethargic, feed poorly, often vomit, and may develop signs of increased intracranial pressure (ICP). Without prompt intervention, hyperammonemia and the accumulation of other toxic metabolites (e.g., glutamine) result in ICP, increased neuromuscular tone, spasticity, ankle clonus, seizures, loss of consciousness, and death. Children with the severe form who are treated promptly may survive for an indeterminate period of time, but usually with significant neurologic deficits. The late-onset form may be milder than that seen in the acute neonatal form, for unknown reasons. The episodes of hyperammonemia are similar to those seen in the acute neonatal form, but the initial neurologic findings may be more subtle because of the older age of the affected individuals.
Dubowitz's syndrome
MedGen UID:
59797
Concept ID:
C0175691
Congenital Abnormality
A syndrome of intrauterine dwarfism, short stature, mental retardation, sparse hair, eczema, and characteristic facies. The phenotype varies from normal growth and head circumference with mild psychomotor retardation and lack of eczema to severe growth and mental retardation, microcephaly, behavioral problems, aplastic anemia, immunological disorders, neoplasms, and eczema Some features of this syndrome are similar to those in Bloom and fetal alcohol syndromes.
Smith-Lemli-Opitz syndrome
MedGen UID:
61231
Concept ID:
C0175694
Disease or Syndrome
Smith-Lemli-Opitz syndrome (SLOS) is a congenital multiple anomaly syndrome caused by an abnormality in cholesterol metabolism resulting from deficiency of the enzyme 7-dehydrocholesterol (7-DHC) reductase. It is characterized by prenatal and postnatal growth retardation, microcephaly, moderate to severe intellectual disability, and multiple major and minor malformations. The malformations include distinctive facial features, cleft palate, cardiac defects, underdeveloped external genitalia in males, postaxial polydactyly, and 2-3 syndactyly of the toes. The clinical spectrum is wide and individuals have been described with normal development and only minor malformations.
Sotos' syndrome
MedGen UID:
61232
Concept ID:
C0175695
Disease or Syndrome
Sotos syndrome is a disorder characterized by a distinctive facial appearance, overgrowth in childhood, and learning disabilities or delayed development of mental and movement abilities. Characteristic facial features include a long, narrow face; a high forehead; flushed (reddened) cheeks; and a small, pointed chin. In addition, the outside corners of the eyes may point downward (down-slanting palpebral fissures). This facial appearance is most notable in early childhood. Affected infants and children tend to grow quickly; they are significantly taller than their siblings and peers and have an unusually large head. However, adult height is usually in the normal range. People with Sotos syndrome often have intellectual disability, and most also have behavioral problems. Frequent behavioral issues include attention deficit hyperactivity disorder (ADHD), phobias, obsessions and compulsions, tantrums, and impulsive behaviors. Problems with speech and language are also common. Affected individuals often have a stutter, a monotone voice, and problems with sound production. Additionally, weak muscle tone (hypotonia) may delay other aspects of early development, particularly motor skills such as sitting and crawling. Other signs and symptoms of Sotos syndrome can include an abnormal side-to-side curvature of the spine (scoliosis), seizures, heart or kidney defects, hearing loss, and problems with vision. Some infants with this disorder experience yellowing of the skin and whites of the eyes (jaundice) and poor feeding. A small percentage of people with Sotos syndrome have developed cancer, most often in childhood, but no single form of cancer occurs most frequently with this condition. It remains uncertain whether Sotos syndrome increases the risk of specific types of cancer. If people with this disorder have an increased cancer risk, it is only slightly greater than that of the general population.
Saethre-Chotzen syndrome
MedGen UID:
64221
Concept ID:
C0175699
Congenital Abnormality
Classic Saethre-Chotzen syndrome (SCS) is characterized by coronal synostosis (unilateral or bilateral), facial asymmetry (particularly in individuals with unilateral coronal synostosis), ptosis, and characteristic appearance of the ear (small pinna with a prominent crus). Syndactyly of digits two and three of the hand is variably present. Intelligence is usually normal, although those with large genomic deletions are more likely to have developmental delays. Less common manifestations of SCS include short stature, parietal foramina, vertebral fusions, radioulnar synostosis, cleft palate, maxillary hypoplasia, ocular hypertelorism, hallux valgus, duplicated distal hallucal phalanx, and congenital heart malformations.
Radial aplasia-thrombocytopenia syndrome
MedGen UID:
61235
Concept ID:
C0175703
Congenital Abnormality
Thrombocytopenia absent radius (TAR) syndrome is characterized by bilateral absence of the radii with the presence of both thumbs and thrombocytopenia (<50 platelets/nL) that is generally transient. Thrombocytopenia may be congenital or may develop within the first few weeks to months of life; in general, thrombocytopenic episodes decrease with age. Cow’s milk allergy is common and can be associated with exacerbation of thrombocytopenia. Other anomalies of the skeleton (upper and lower limbs, ribs, and vertebrae), heart, and genitourinary system (renal anomalies and agenesis of uterus, cervix, and upper part of the vagina) can occur.
Aicardi's syndrome
MedGen UID:
61236
Concept ID:
C0175713
Disease or Syndrome
Aicardi syndrome was classically characterized by a triad of features: agenesis of the corpus callosum, distinctive chorioretinal lacunae, and infantile spasms. However, it is now well recognized that several other important findings are typically present in girls with Aicardi syndrome. Neurologic examination can reveal microcephaly, axial hypotonia, and appendicular hypertonia with spasticity. Moderate to severe global developmental delay and intellectual disability are expected. Many girls with Aicardi syndrome develop seizures prior to age three months, and most before age one year. Ongoing medically refractory epilepsy with a variety of seizure types develops over time. Costovertebral defects are common and can lead to marked scoliosis in up to one third of affected individuals. Other features include characteristic facial features, gastrointestinal difficulties, small hands, vascular malformations and pigmentary lesions of the skin, increased incidence of tumors, lower growth rate after ages seven to nine years, and precocious or delayed puberty. Survival is highly variable, with the mean age of death about 8.3 years and the median age of death about 18.5 years.
Progressive sclerosing poliodystrophy
MedGen UID:
60012
Concept ID:
C0205710
Disease or Syndrome
POLG-related disorders comprise a continuum of overlapping phenotypes that were clinically defined long before their molecular basis was known. These phenotypes exemplify the diversity that can result from mutation of a given gene. Most affected individuals have some, but not all, of the features of a given phenotype; nonetheless, the following nomenclature can assist the clinician in diagnosis and management. Onset of the POLG-related disorders ranges from infancy to late adulthood. Alpers-Huttenlocher syndrome (AHS), one of the most severe phenotypes, is characterized by childhood-onset progressive and ultimately severe encephalopathy with intractable epilepsy and hepatic failure. Childhood myocerebrohepatopathy spectrum (MCHS) presents between the first few months of life up to about age three years with developmental delay or dementia, lactic acidosis, and a myopathy with failure to thrive. Other findings can include liver failure, renal tubular acidosis, pancreatitis, cyclic vomiting, and hearing loss. Myoclonic epilepsy myopathy sensory ataxia (MEMSA) now describes the spectrum of disorders with epilepsy, myopathy, and ataxia without ophthalmoplegia. MEMSA now includes the disorders previously described as spinocerebellar ataxia with epilepsy (SCAE). The ataxia neuropathy spectrum (ANS) includes the phenotypes previously referred to as mitochondrial recessive ataxia syndrome (MIRAS) and sensory ataxia neuropathy dysarthria and ophthalmoplegia (SANDO). About 90% of persons in the ANS have ataxia and neuropathy as core features. Approximately two thirds develop seizures and almost one half develop ophthalmoplegia; clinical myopathy is rare. Autosomal recessive progressive external ophthalmoplegia (arPEO) is characterized by progressive weakness of the extraocular eye muscles resulting in ptosis and ophthalmoparesis (or paresis of the extraocular muscles) without associated systemic involvement; however, caution is advised because many individuals with apparently isolated arPEO at the onset develop other manifestations of POLG-related disorders over years or decades. Of note, in the ANS spectrum the neuropathy commonly precedes the onset of PEO by years to decades. Autosomal dominant progressive external ophthalmoplegia (adPEO) typically includes a generalized myopathy and often variable degrees of sensorineural hearing loss, axonal neuropathy, ataxia, depression, Parkinsonism, hypogonadism, and cataracts (in what has been called “chronic progressive external ophthalmoplegia plus,” or “CPEO+”).
Pelizaeus-Merzbacher disease
MedGen UID:
61440
Concept ID:
C0205711
Disease or Syndrome
PLP1-related disorders of central nervous system myelin formation include a range of phenotypes from Pelizaeus-Merzbacher disease (PMD) to spastic paraplegia 2 (SPG2). PMD typically manifests in infancy or early childhood with nystagmus, hypotonia, and cognitive impairment; the findings progress to severe spasticity and ataxia. Life span is shortened. SPG2 manifests as spastic paraparesis with or without CNS involvement and usually normal life span. Intrafamilial variation of phenotypes can be observed, but the signs are usually fairly consistent within families. Female carriers may manifest mild to moderate signs of the disease.
Choroid plexus papilloma
MedGen UID:
64439
Concept ID:
C0205770
Neoplastic Process
Choroid plexus tumors are of neuroectodermal origin and range from benign choroid plexus papillomas (CPPs) to malignant choroid carcinomas (CPCs). These rare tumors generally occur in childhood, but have also been reported in adults. Patients typically present with signs and symptoms of increased intracranial pressure including headache, hydrocephalus, papilledema, nausea, vomiting, cranial nerve deficits, gait impairment, and seizures (summary by Safaee et al., 2013).
Spongy degeneration of central nervous system
MedGen UID:
61565
Concept ID:
C0206307
Disease or Syndrome
Neonatal/infantile (severe) Canavan disease is characterized by macrocephaly, lack of head control, and developmental delays usually noted by age three to five months. As children get older hypotonia becomes severe and failure to achieve independent sitting, ambulation, or speech become apparent. Hypotonia eventually changes to spasticity. Assistance with feeding becomes necessary. Life expectancy is usually into the teens. Mild/juvenile Canavan disease is characterized by mild developmental delay that can go unrecognized. Head circumference may be normal.
Medium-chain acyl-coenzyme A dehydrogenase deficiency
MedGen UID:
65086
Concept ID:
C0220710
Disease or Syndrome
Medium-chain acyl-coenzyme A dehydrogenase (MCAD) is one of the enzymes involved in mitochondrial fatty acid ß-oxidation, which fuels hepatic ketogenesis, a major source of energy once hepatic glycogen stores become depleted during prolonged fasting and periods of higher energy demands. In a typical clinical scenario, a previously healthy child with MCAD deficiency presents with hypoketotic hypoglycemia, vomiting, and lethargy triggered by a common illness. Seizures may occur. Hepatomegaly and liver disease are often present during an acute episode, which can quickly progress to coma and death. Children are normal at birth and – if not identified through newborn screening – typically present between ages three and 24 months; later presentation, even into adulthood, is possible. The prognosis is excellent once the diagnosis is established and frequent feedings are instituted to avoid any prolonged period of fasting.
Cerebro-oculo-facio-skeletal syndrome
MedGen UID:
66320
Concept ID:
C0220722
Congenital Abnormality
Cerebrooculofacioskeletal syndrome is an autosomal recessive progressive neurodegenerative disorder characterized by microcephaly, congenital cataracts, severe mental retardation, facial dysmorphism, and arthrogryposis (summary by Jaakkola et al., 2010). Genetic Heterogeneity of Cerebrooculofacioskeletal Syndrome See also COFS2 (610756), caused by mutation in the ERCC2 gene (126340); COFS3, also known as XPG/CS syndrome (see 278780), caused by mutation in the ERCC5 gene (133530); and COFS4 (610758), caused by mutation in the ERCC1 gene (126380).
Fryns syndrome
MedGen UID:
65088
Concept ID:
C0220730
Disease or Syndrome
Fryns syndrome is characterized by diaphragmatic defects (diaphragmatic hernia, eventration, hypoplasia or agenesis); characteristic facial appearance (coarse facies, ocular hypertelorism, broad and flat nasal bridge, thick nasal tip, long philtrum, low-set and poorly formed ears, tented upper lip, macrostomia, micrognathia); distal digital hypoplasia (nails, terminal phalanges); pulmonary hypoplasia; and associated anomalies (polyhydramnios, cloudy corneas and/or microphthalmia, orofacial clefting, renal dysplasia/renal cortical cysts, and/or malformations involving the brain, cardiovascular system, gastrointestinal system, genitalia). Survival beyond the neonatal period has been rare. Data on postnatal growth and psychomotor development are limited; however, severe developmental delay and intellectual disability are common.
Childhood hypophosphatasia
MedGen UID:
65089
Concept ID:
C0220743
Congenital Abnormality
Hypophosphatasia is characterized by defective mineralization of bone and/or teeth in the presence of low activity of serum and bone alkaline phosphatase. Clinical features range from stillbirth without mineralized bone at the severe end to pathologic fractures of the lower extremities in later adulthood at the mild end. At least six clinical forms are currently recognized based on age at diagnosis and severity of features: Perinatal (lethal) hypophosphatasia characterized by respiratory insufficiency and hypercalcemia. Perinatal (benign) hypophosphatasia with prenatal skeletal manifestations that slowly resolve into the milder childhood or adult form. Infantile hypophosphatasia with onset between birth and age six months of rickets without elevated serum alkaline phosphatase activity. Childhood hypophosphatasia that ranges from low bone mineral density for age with unexplained fractures to rickets. Adult hypophosphatasia characterized by early loss of adult dentition and stress fractures and pseudofractures of the lower extremities in middle age. Odontohypophosphatasia characterized by premature exfoliation of primary teeth and/or severe dental caries as an isolated finding or as part of the above forms of hypophosphatasia.
Biotinidase deficiency
MedGen UID:
66323
Concept ID:
C0220754
Disease or Syndrome
If untreated, young children with profound biotinidase deficiency usually exhibit neurologic abnormalities including seizures, hypotonia, ataxia, developmental delay, vision problems, hearing loss, and cutaneous abnormalities (e.g., alopecia, skin rash, candidiasis). Older children and adolescents with profound biotinidase deficiency often exhibit motor limb weakness, spastic paresis, and decreased visual acuity. Once vision problems, hearing loss, and developmental delay occur, they are usually irreversible, even with biotin therapy. Individuals with partial biotinidase deficiency may have hypotonia, skin rash, and hair loss, particularly during times of stress.
FG syndrome
MedGen UID:
113106
Concept ID:
C0220769
Disease or Syndrome
The phenotypic spectrum of MED12-related disorders, which is still being defined, includes at a minimum the phenotypes of FG syndrome type 1 (FGS1) and Lujan syndrome (LS). FGS1 and LS share the clinical findings of cognitive impairment, hypotonia, and abnormalities of the corpus callosum. FGS1 is further characterized by absolute or relative macrocephaly, tall forehead, downslanted palpebral fissures, small and simple ears, constipation and/or anal anomalies, broad thumbs and halluces, and characteristic behavior. LS is further characterized by large head, tall thin body habitus, long thin face, high nasal root, high narrow palate, and short philtrum. Carrier females in families with FGS1 and LS are typically unaffected.
Acquired partial lipodystrophy
MedGen UID:
66352
Concept ID:
C0220989
Disease or Syndrome
Acquired partial lipodystrophy is characterized clinically by the gradual onset of bilaterally symmetrical loss of subcutaneous fat from the face, neck, upper extremities, thorax, and abdomen, in the 'cephalocaudal' sequence, sparing the lower extremities (summary by Misra et al., 2004). The disorder is not inherited in a classic mendelian pattern; it rather represents a phenotype with a complex etiology. Affected individuals may have genetic susceptibility factors that require the additional presence of environmental factors or acquired disorders to be expressed (summary by Hegele et al., 2006). Most cases are sporadic, family history is negative, and females are more often affected than males (ratio, 4:1). There is an association between APLD and autoimmune diseases (Misra and Garg, 2003; Misra et al., 2004), and a subset of patients have APLD associated with low serum complement component C3 and the autoantibody C3 nephritic factor, with or without membranoproliferative glomerulonephritis (APLDC3; 613913). Acquired partial lipodystrophy is distinct from inherited forms of partial lipodystrophy, which are metabolic disorders that show clear mendelian inheritance (see, e.g., FPLD1, 608600).
Degos disease
MedGen UID:
113138
Concept ID:
C0221011
Disease or Syndrome
Variously described as a vasculopathy, endovasculitis, or occlusive arteriopathy, this condition occurs in a benign cutaneous form and a lethal multiorgan systemic variant. It is characterized by a narrowing and occlusion of the lumen of small to medium-sized blood vessels, leading to ischemia and infarction in the involved organ systems. The etiology and pathophysiology are unknown.
Cholestanol storage disease
MedGen UID:
116041
Concept ID:
C0238052
Disease or Syndrome
Cerebrotendinous xanthomatosis (CTX) is a lipid storage disease characterized by infantile-onset diarrhea, childhood-onset cataract, adolescent- to young adult-onset tendon xanthomas, and adult-onset progressive neurologic dysfunction (dementia, psychiatric disturbances, pyramidal and/or cerebellar signs, dystonia, atypical parkinsonism, peripheral neuropathy, and seizures). Chronic diarrhea from infancy may be the earliest clinical manifestation. In approximately 75% of affected individuals, cataracts are the first finding, often appearing in the first decade of life. Xanthomas appear in the second or third decade; they occur on the Achilles tendon, the extensor tendons of the elbow and hand, the patellar tendon, and the neck tendons. Xanthomas have been reported in the lung, bones, and central nervous system. Some individuals show mental impairment from early infancy, whereas the majority have normal or only slightly subnormal intellectual function until puberty; dementia with slow deterioration in intellectual abilities occurs in the 20s in more than 50% of individuals. Neuropsychiatric symptoms such as behavioral changes, hallucinations, agitation, aggression, depression, and suicide attempts may be prominent. Pyramidal signs (i.e., spasticity) and/or cerebellar signs almost invariably become evident between ages 20 and 30 years.
Facioscapulohumeral muscular dystrophy
MedGen UID:
65956
Concept ID:
C0238288
Disease or Syndrome
Facioscapulohumeral muscular dystrophy (FSHD) typically presents before age 20 years with weakness of the facial muscles and the stabilizers of the scapula or the dorsiflexors of the foot. Severity is highly variable. Weakness is slowly progressive and approximately 20% of affected individuals eventually require a wheelchair. Life expectancy is not shortened.
Seckel syndrome
MedGen UID:
78534
Concept ID:
C0265202
Disease or Syndrome
A syndrome of proportionate dwarfism, delayed mental development, microcephaly, and typical facial appearance marked by a birdlike protrusion of midfacial structures.
Weaver syndrome
MedGen UID:
120511
Concept ID:
C0265210
Congenital Abnormality
EZH2-related overgrowth includes EZH2-related Weaver syndrome at one end of the spectrum and tall stature at the other. Although most individuals diagnosed with a heterozygous EZH2 pathogenic variant have been identified because of a clinical suspicion of Weaver syndrome, a minority have been identified through molecular genetic testing of family members of probands or individuals with overgrowth who did not have a clinical diagnosis of Weaver syndrome. Thus, the extent of the phenotypic spectrum associated with a heterozygous EZH2 pathogenic variant is not yet known. Weaver syndrome is characterized by tall stature, variable intellect (ranging from normal intellect to severe intellectual disability), characteristic facial appearance, and a range of associated clinical features including advanced bone age, poor coordination, soft doughy skin, camptodactyly of the fingers or toes, umbilical hernia, abnormal tone, and hoarse low cry in infancy. Neuronal migration disorders have also been reported in a few individuals with EZH2-related overgrowth. Neuroblastoma occurs at a slightly increased frequency in individuals with a heterozygous EZH2 pathogenic variant but data are insufficient to determine absolute risk. There is currently no evidence that additional malignancies (including hematologic malignancies) occur with increased frequency.
X-linked hydrocephalus syndrome
MedGen UID:
75552
Concept ID:
C0265216
Disease or Syndrome
The phenotypic spectrum of L1 syndrome includes: X-linked hydrocephalus with stenosis of the aqueduct of Sylvius (HSAS); MASA syndrome (mental retardation, aphasia [delayed speech], spastic paraplegia [shuffling gait], adducted thumbs); SPG1 (X-linked complicated hereditary spastic paraplegia type 1); and X-linked complicated corpus callosum agenesis. Males with HSAS are born with severe hydrocephalus, adducted thumbs, and spasticity; intellectual disability is severe. In less severely affected males, hydrocephalus may be subclinically present and documented only because of developmental delay; intellectual disability ranges from mild (IQ: 50-70) to moderate (IQ: 30-50).
Miller Dieker syndrome
MedGen UID:
78538
Concept ID:
C0265219
Disease or Syndrome
LIS1-associated lissencephaly includes Miller-Dieker syndrome (MDS), isolated lissencephaly sequence (ILS), and (rarely) subcortical band heterotopia (SBH). Lissencephaly and SBH are cortical malformations caused by deficient neuronal migration during embryogenesis. Lissencephaly refers to a "smooth brain" with absent gyri (agyria) or abnormally wide gyri (pachygyria). SBH refers to a band of heterotopic gray matter located just beneath the cortex and separated from it by a thin zone of normal white matter. MDS is characterized by lissencephaly, typical facial features, and severe neurologic abnormalities. ILS is characterized by lissencephaly and its direct sequelae: developmental delay, intellectual disability, and seizures.
Pallister-Hall syndrome
MedGen UID:
120514
Concept ID:
C0265220
Disease or Syndrome
Pallister-Hall syndrome (referred to as PHS in this entry) is characterized by a spectrum of anomalies ranging from polydactyly, asymptomatic bifid epiglottis, and hypothalamic hamartoma at the mild end to laryngotracheal cleft with neonatal lethality at the severe end. Individuals with mild PHS may be incorrectly diagnosed as having isolated postaxial polydactyly type A. Individuals with PHS can have pituitary insufficiency and may die as neonates from undiagnosed and untreated adrenal insufficiency.
Walker-Warburg congenital muscular dystrophy
MedGen UID:
75553
Concept ID:
C0265221
Congenital Abnormality
Congenital muscular dystrophy (CMD) is a clinically and genetically heterogeneous group of inherited muscle disorders. Muscle weakness typically presents from birth to early infancy. Affected infants typically appear "floppy" with low muscle tone and poor spontaneous movements. Affected children may present with delay or arrest of gross motor development together with joint and/or spinal rigidity. Muscle weakness may improve, worsen, or stabilize in the short term; however, with time progressive weakness and joint contractures, spinal deformities, and respiratory compromise may affect quality of life and life span. The main CMD subtypes, grouped by involved protein function and gene in which causative mutations occur, are laminin alpha-2 (merosin) deficiency (MDC1A), collagen VI-deficient CMD, the dystroglycanopathies (caused by mutations in POMT1, POMT2, FKTN, FKRP, LARGE, POMGNT1, and ISPD), SEPN1-related CMD (previously known as rigid spine syndrome, RSMD1) and LMNA-related CMD (L-CMD). Several less known CMD subtypes have been reported in a limited number of individuals. Cognitive impairment ranging from intellectual disability to mild cognitive delay, structural brain and/or eye abnormalities, and seizures are found almost exclusively in the dystroglycanopathies while white matter abnormalities without major cognitive involvement tend to be seen in the laminin alpha-2-deficient subtype.
Cohen syndrome
MedGen UID:
78539
Concept ID:
C0265223
Disease or Syndrome
Cohen syndrome is characterized by failure to thrive in infancy and childhood; truncal obesity in the teen years; early-onset hypotonia and developmental delays; microcephaly developing during the first year of life; moderate to profound psychomotor retardation; progressive retinochoroidal dystrophy and high myopia; neutropenia in many with recurrent infections and aphthous ulcers in some; a cheerful disposition; joint hypermobility; and characteristic facial features.
Freeman-Sheldon syndrome
MedGen UID:
120516
Concept ID:
C0265224
Congenital Abnormality
Freeman-Sheldon syndrome (FSS), or DA2A, is phenotypically similar to DA1. In addition to contractures of the hands and feet, FSS is characterized by oropharyngeal abnormalities, scoliosis, and a distinctive face that includes a very small oral orifice (often only a few millimeters in diameter at birth), puckered lips, and an H-shaped dimple of the chin; hence, FSS has been called 'whistling face syndrome.' The limb phenotypes of DA1 and FSS may be so similar that they can only be distinguished by the differences in facial morphology (summary by Bamshad et al., 2009). For a general phenotypic description and a discussion of genetic heterogeneity of distal arthrogryposis, see DA1 (108120).
Ruvalcaba syndrome
MedGen UID:
120520
Concept ID:
C0265248
Disease or Syndrome
A dysmorphic syndrome characterized by short stature, microcephaly, mental deficiency, peculiar facies, hypoplastic genitalia, and skeletal anomalies.
Coffin-Lowry syndrome
MedGen UID:
75556
Concept ID:
C0265252
Disease or Syndrome
Coffin-Lowry syndrome (CLS) is usually characterized by severe-to-profound intellectual disability in males; less severely impaired individuals have been reported. Intellect ranges from normal to profoundly impaired in heterozygous females. The facial appearance is characteristic in the affected, older male child or adult. The hands are short, soft, and fleshy, often with remarkably hyperextensible fingers that taper from wide (proximally) to narrow with small terminal phalanges and nails. Males are consistently below the third centile in height. Microcephaly is common. Cardiac abnormalities may be present and can contribute to premature death. Stimulus-induced drop attacks (SIDAs) in which unexpected tactile or auditory stimuli or excitement triggers a brief collapse but no loss of consciousness are present in approximately 20% of affected individuals. Typically SIDAs begin between mid-childhood and the teens. Progressive kyphoscoliosis is one of the most difficult aspects of long-term care. Life span may be reduced.
Adams-Oliver syndrome
MedGen UID:
78544
Concept ID:
C0265268
Disease or Syndrome
Adams-Oliver syndrome (AOS) is a rare developmental disorder defined by the combination of aplasia cutis congenita of the scalp vertex and terminal transverse limb defects (e.g., amputations, syndactyly, brachydactyly, or oligodactyly). In addition, vascular anomalies such as cutis marmorata telangiectatica congenita, pulmonary hypertension, portal hypertension, and retinal hypervascularization are recurrently seen. Congenital heart defects have been estimated to be present in 20% of AOS patients; reported malformations include ventricular septal defects, anomalies of the great arteries and their valves, and tetralogy of Fallot (summary by Stittrich et al., 2014). Genetic Heterogeneity of Adams-Oliver Syndrome Other autosomal dominant forms of Adams-Oliver syndrome include AOS3 (614814), caused by mutation in the RBPJ gene (147183) on chromosome 4p15, and AOS5 (616028), caused by mutation in the NOTCH1 gene (190198) on chromosome 9q34. Autosomal recessive forms of Adams-Oliver syndrome include AOS2 (614219), caused by mutation in the DOCK6 gene (614194) on chromosome 19p13.2, and AOS4 (615297), caused by mutation in the EOGT gene (614789) on chromosome 3p14.
Geleophysic dysplasia
MedGen UID:
78549
Concept ID:
C0265287
Congenital Abnormality
Geleophysic dysplasia, a progressive condition resembling a lysosomal storage disorder, is characterized by short stature, short hands and feet, progressive joint limitation and contractures, distinctive facial features, progressive cardiac valvular disease, and thickened skin. Intellect is normal. Major findings are likely to be present in the first year of life. Cardiac, respiratory, and lung involvement result in death before age five years in approximately 33% of individuals with geleophysic dysplasia 1.
Kenny-Caffey syndrome
MedGen UID:
75560
Concept ID:
C0265291
Disease or Syndrome
In the classical form, the syndrome involves the skeletal and endocrine system and is manifested by inner cortical thickening with stenosis of the medullary cavities of the tubular bones, short stature, episodes of hypocalcemia due to hypoparathyroidism, and macrocephaly. The phenotype was expanded in later cases to include central nervous system and immunological disorders and psychomotor retardation.
Greig cephalopolysyndactyly syndrome
MedGen UID:
120531
Concept ID:
C0265306
Disease or Syndrome
Typical Greig cephalopolysyndactyly syndrome (GCPS) is characterized by preaxial polydactyly or mixed pre- and postaxial polydactyly, true widely spaced eyes, and macrocephaly. Individuals with mild GCPS may have subtle craniofacial findings. The mild end of the GCPS spectrum is a continuum with preaxial polysyndactyly type IV and crossed polydactyly (preaxial polydactyly of the feet and postaxial polydactyly of the hands plus syndactyly of fingers 3-4 and toes 1-3). Individuals with severe GCPS can have seizures, hydrocephalus, and intellectual disability.
Baller-Gerold syndrome
MedGen UID:
120532
Concept ID:
C0265308
Disease or Syndrome
Baller-Gerold syndrome (BGS) is characterized by coronal craniosynostosis, manifest as abnormal shape of the skull (brachycephaly) with ocular proptosis and bulging forehead; radial ray defect, manifest as oligodactyly (reduction in number of digits), aplasia or hypoplasia of the thumb, and/or aplasia or hypoplasia of the radius; growth retardation and poikiloderma. Findings in individuals with BGS overlap with those of Rothmund-Thomson syndrome (RTS) and RAPADILINO syndrome, also caused by mutations in RECQL4. RTS is characterized by poikiloderma; sparse hair, eyelashes, and/or eyebrows/lashes; small stature; skeletal and dental abnormalities; cataracts; and an increased risk for cancer, especially osteosarcoma. RAPADILINO syndrome is an acronym for RAdial ray defect; PAtellae hypoplasia or aplasia and cleft or highly arched PAlate; DIarrhea and DIslocated joints; LIttle size and LImb malformation; NOse slender and NOrmal intelligence.
Epidermal nevus syndrome
MedGen UID:
120533
Concept ID:
C0265318
Disease or Syndrome
Schimmelpenning-Feuerstein-Mims syndrome, also known as linear sebaceous nevus syndrome, is characterized by sebaceous nevi, often on the face, associated with variable ipsilateral abnormalities of the central nervous system, ocular anomalies, and skeletal defects (summary by Happle, 1991 and Ernst et al., 2007). The linear sebaceous nevi follow the lines of Blaschko (Hornstein and Knickenberg, 1974; Bouwes Bavinck and van de Kamp, 1985). All cases are sporadic. The syndrome is believed to be caused by an autosomal dominant lethal mutation that survives by somatic mosaicism (Gorlin et al., 2001).
Turcot syndrome
MedGen UID:
78553
Concept ID:
C0265325
Disease or Syndrome
Lynch syndrome, caused by a germline pathogenic variant in a mismatch repair gene and associated with tumors exhibiting microsatellite instability (MSI), is characterized by an increased risk for colon cancer and cancers of the endometrium, ovary, stomach, small intestine, hepatobiliary tract, urinary tract, brain, and skin. In individuals with Lynch syndrome the following life time risks for cancer are seen: 52%-82% for colorectal cancer (mean age at diagnosis 44-61 years); 25%-60% for endometrial cancer in women (mean age at diagnosis 48-62 years); 6% to 13% for gastric cancer (mean age at diagnosis 56 years); and 4%-12% for ovarian cancer (mean age at diagnosis 42.5 years; approximately 30% are diagnosed before age 40 years). The risk for other Lynch syndrome-related cancers is lower, though substantially increased over general population rates.
Bannayan-Riley-Ruvalcaba syndrome
MedGen UID:
78554
Concept ID:
C0265326
Congenital Abnormality
The PTEN hamartoma tumor syndrome (PHTS) includes Cowden syndrome (CS), Bannayan-Riley-Ruvalcaba syndrome (BRRS), PTEN-related Proteus syndrome (PS), and Proteus-like syndrome. CS is a multiple hamartoma syndrome with a high risk for benign and malignant tumors of the thyroid, breast, and endometrium. Affected individuals usually have macrocephaly, trichilemmomas, and papillomatous papules, and present by the late 20s. The lifetime risk of developing breast cancer is 85%, with an average age of diagnosis between 38 and 46 years. The lifetime risk for thyroid cancer (usually follicular, rarely papillary, but never medullary thyroid cancer) is approximately 35%. The risk for endometrial cancer, although not well defined, may approach 28%. BRRS is a congenital disorder characterized by macrocephaly, intestinal hamartomatous polyposis, lipomas, and pigmented macules of the glans penis. PS is a complex, highly variable disorder involving congenital malformations and hamartomatous overgrowth of multiple tissues, as well as connective tissue nevi, epidermal nevi, and hyperostoses. Proteus-like syndrome is undefined but refers to individuals with significant clinical features of PS who do not meet the diagnostic criteria for PS.
Moynahan's syndrome
MedGen UID:
120535
Concept ID:
C0265328
Congenital Abnormality
Alopecia or hypotrichosis, microcephaly, seizures, and mental retardation. A suggested classification groups this syndrome into three types: Type I. Total alopecia and mental retardation, the main features, in association with microcephaly. Type II. Subtotal alopecia and mental retardation with or without epilepsy. Type III. Subtotal alopecia and psychomotor retardation with microcephaly and epilepsy.
Coffin-Siris syndrome
MedGen UID:
75565
Concept ID:
C0265338
Congenital Abnormality
Coffin-Siris syndrome (CSS) is characterized by aplasia or hypoplasia of the distal phalanx or nail of the fifth digit, distinctive facial features, and moderate to severe developmental/cognitive delay. Expressive language is more severely affected than receptive language. On average, children with CSS learn to sit at 12 months, walk at 30 months, and speak their first words at 24 months. Other findings commonly include failure to thrive, feeding difficulties, short stature, ophthalmologic abnormalities, microcephaly, brain malformations, and hearing loss.
Borjeson-Forssman-Lehmann syndrome
MedGen UID:
78557
Concept ID:
C0265339
Disease or Syndrome
Microcephaly, characteristic facies (swelling, p prominent supraorbital ridges and narrow palpebral fissures), obesity, epilepsy, and hypogonadism, and mental deficiency.
Pallister-Killian syndrome
MedGen UID:
120540
Concept ID:
C0265449
Disease or Syndrome
Pallister-Killian syndrome is a dysmorphic condition involving most organ systems, but also characterized by a tissue-limited mosaicism; most fibroblasts have 47 chromosomes with an extra small metacentric chromosome, whereas the karyotype of lymphocytes is normal. The extra metacentric chromosome is an isochromosome for part of the short arm of chromosome 12: i(12)(p10) (Peltomaki et al., 1987; Warburton et al., 1987).
Congenital absence of lung
MedGen UID:
82722
Concept ID:
C0265780
Congenital Abnormality
The Mardini-Nyhan association comprises uni- or bilateral lung agenesis, complex cardiac defects, particularly total anomalous pulmonary venous return (TAPVR), and thumb abnormalities (summary by Hastings et al., 2009).
Netherton syndrome
MedGen UID:
78578
Concept ID:
C0265962
Disease or Syndrome
Netherton syndrome is a disorder that affects the skin, hair, and immune system. Newborns with Netherton syndrome have skin that is red and scaly (ichthyosiform erythroderma), and the skin may leak fluid. Some affected infants are born with a tight, clear sheath covering their skin called a collodion membrane. This membrane is usually shed during the first few weeks of life. Because newborns with this disorder are missing the protection provided by normal skin, they are at risk of becoming dehydrated and developing infections in the skin or throughout the body (sepsis), which can be life-threatening. Affected babies may also fail to grow and gain weight at the expected rate (failure to thrive). The health of older children and adults with Netherton syndrome usually improves, although they often remain underweight and of short stature. After infancy, the severity of the skin abnormalities varies among people with Netherton syndrome and can fluctuate over time. The skin may continue to be red and scaly, especially during the first few years of life. Some affected individuals have intermittent redness or experience outbreaks of a distinctive skin abnormality called ichthyosis linearis circumflexa, involving patches of multiple ring-like lesions. The triggers for the outbreaks are not known, but researchers suggest that stress or infections may be involved. Itchiness is a common problem for affected individuals, and scratching can lead to frequent infections. Dead skin cells are shed at an abnormal rate and often accumulate in the ear canals, which can affect hearing if not removed regularly. The skin is abnormally absorbent of substances such as lotions and ointments, which can result in excessive blood levels of some topical medications. Because the ability of the skin to protect against heat and cold is impaired, affected individuals may have difficulty regulating their body temperature. People with Netherton syndrome have hair that is fragile and breaks easily. Some strands of hair vary in diameter, with thicker and thinner spots. This feature is known as bamboo hair, trichorrhexis nodosa, or trichorrhexis invaginata. In addition to the hair on the scalp, the eyelashes and eyebrows may be affected. The hair abnormality in Netherton syndrome may not be noticed in infancy because babies often have sparse hair. Most people with Netherton syndrome have immune system-related problems such as food allergies, hay fever, asthma, or an inflammatory skin disorder called eczema.
Schizencephaly
MedGen UID:
78606
Concept ID:
C0266484
Disease or Syndrome
Brunelli et al. (1996) described schizencephaly as an extremely rare congenital disorder characterized by a full-thickness cleft within the cerebral hemispheres. The clefts are lined with gray matter and most commonly involve the parasylvian regions (Wolpert and Barnes, 1992). Large portions of the cerebral hemispheres may be absent and replaced by cerebrospinal fluid. Two types of schizencephaly have been described, depending on the size of the area involved and the separation of the cleft lips (Wolpert and Barnes, 1992). Type I schizencephaly consists of a fused cleft. This fused pial-ependymal seam forms a furrow in the developing brain, and is lined by polymicrogyric gray matter. In type II schizencephaly, there is a large defect, a holohemispheric cleft in the cerebral cortex filled with fluid and lined by polymicrogyric gray matter. The clinical manifestations depend on the severity of the lesion. Patients with type I are often almost normal; they may have seizures and spasticity. In type II abnormalities, there is usually mental retardation, seizures, hypotonia, spasticity, inability to walk or speak, and blindness. Schizencephaly may be part of the larger phenotypic spectrum of holoprosencephaly (HPE; see 236100).
Atrophia bulborum hereditaria
MedGen UID:
75615
Concept ID:
C0266526
Congenital Abnormality
NDP-related retinopathies are characterized by a spectrum of fibrous and vascular changes of the retina at birth that progress through childhood or adolescence to cause varying degrees of visual impairment. The most severe phenotype is described as Norrie disease (ND), characterized by greyish yellow fibrovascular masses (pseudogliomas) secondary to retinal vascular dysgenesis and detachment. Congenital blindness is almost always present. Approximately 30%-50% of males with ND have developmental delay/intellectual disability, behavioral abnormalities, or psychotic-like features. The majority of males with ND develop sensorineural hearing loss. Less severe phenotypes include: persistent hyperplastic primary vitreous (PHPV), characterized by a fibrotic white stalk from the optic disk to the lens; X-linked familial exudative vitreoretinopathy (XL-FEVR), characterized by peripheral retinal vascular anomalies with or without fibrotic changes and retinal detachment; retinopathy of prematurity (ROP); and Coats disease, an exudative proliferative vasculopathy. Phenotypes can vary within families.
Combined molybdoflavoprotein enzyme deficiency
MedGen UID:
75652
Concept ID:
C0268119
Disease or Syndrome
Molybdenum cofactor deficiency (MOCOD) is a rare autosomal recessive metabolic disorder characterized by onset in infancy of poor feeding, intractable seizures, and severe psychomotor retardation. Characteristic biochemical abnormalities include decreased serum uric acid and increased urine sulfite levels due to the combined enzymatic deficiency of xanthine dehydrogenase (XDH; 607633) and sulfite oxidase (SUOX; 606887), both of which use molybdenum as a cofactor. Most affected individuals die in early childhood (summary by Reiss, 2000; Reiss et al., 2011). Genetic Heterogeneity of Molybdenum Cofactor Deficiency See also MOCOD, complementation group B (MOCODB; 252160), caused by mutation in the MOCS2 gene (602708) on chromosome 5q11; and MOCOD, complementation group C (MOCODC; 615501), caused by mutation in the GPHN gene (603930) on chromosome 14q24.
Adenylosuccinate lyase deficiency
MedGen UID:
78641
Concept ID:
C0268126
Disease or Syndrome
Adenylosuccinate lyase deficiency is a neurological disorder that causes brain dysfunction (encephalopathy) leading to delayed development of mental and movement abilities (psychomotor delay), autistic behaviors that affect communication and social interaction, and seizures. A characteristic feature that can help with diagnosis of this condition is the presence of chemicals called succinylaminoimidazole carboxamide riboside (SAICAr) and succinyladenosine (S-Ado) in body fluids. Adenylosuccinate lyase deficiency is classified into three forms based on the severity of the signs and symptoms. The most severe is the neonatal form. Signs and symptoms of this form can be detected at or before birth and can include impaired growth during fetal development and a small head size (microcephaly). Affected newborns have severe encephalopathy, which leads to a lack of movement, difficulty feeding, and life-threatening respiratory problems. Some affected babies develop seizures that do not improve with treatment. Because of the severity of the encephalopathy, infants with this form of the condition generally do not survive more than a few weeks after birth. Adenylosuccinate lyase deficiency type I (also known as the severe form) is the most common. The signs and symptoms of this form begin in the first months of life. Affected babies have severe psychomotor delay, weak muscle tone (hypotonia), and microcephaly. Many affected infants develop recurrent seizures that are difficult to treat, and some exhibit autistic behaviors, such as repetitive behaviors and a lack of eye contact. In individuals with adenylosuccinate lyase deficiency type II (also known as the moderate or mild form), development is typically normal for the first few years of life but then slows. Psychomotor delay is considered mild or moderate. Some children with this form of the condition develop seizures and autistic behaviors.
Deficiency of cytochrome-b5 reductase
MedGen UID:
75661
Concept ID:
C0268193
Disease or Syndrome
Methemoglobinemia due to NADH-cytochrome b5 reductase deficiency is an autosomal recessive disorder characterized clinically by decreased oxygen carrying capacity of the blood, with resultant cyanosis and hypoxia (review by Percy and Lappin, 2008). There are 2 types of methemoglobin reductase deficiency. In type I, the defect affects the soluble form of the enzyme, is restricted to red blood cells, and causes well-tolerated methemoglobinemia. In type II, the defect affects both the soluble and microsomal forms of the enzyme and is thus generalized, affecting red cells, leukocytes, and all body tissues. Type II methemoglobinemia is associated with mental deficiency and other neurologic symptoms. The neurologic symptoms may be related to the major role played by the cytochrome b5 system in the desaturation of fatty acids (Vives-Corrons et al., 1978; Kaplan et al., 1979).
Aspartylglycosaminuria
MedGen UID:
78649
Concept ID:
C0268225
Disease or Syndrome
Aspartylglucosaminuria is a severe autosomal recessive lysosomal storage disorder that involves the central nervous system and causes skeletal abnormalities as well as connective tissue lesions. The most characteristic feature is progressive mental retardation. The disorder is caused by deficient activity of the lysosomal enzyme glycosylasparaginase, which results in body fluid and tissue accumulation of a series of glycoasparagines, i.e., glycoconjugates with an aspartylglucosamine moiety at the reducing end. AGU belongs to the group of disorders commonly referred to as the Finnish disease heritage (summary by Mononen et al., 1993 and Arvio and Arvio, 2002).
Sialidosis, type II
MedGen UID:
120621
Concept ID:
C0268226
Disease or Syndrome
Sialidosis is an autosomal recessive disorder characterized by the progressive lysosomal storage of sialylated glycopeptides and oligosaccharides caused by a deficiency of the enzyme neuraminidase. Common to the sialidoses is the accumulation and/or excretion of sialic acid (N-acetylneuraminic acid) covalently linked ('bound') to a variety of oligosaccharides and/or glycoproteins (summary by Lowden and O'Brien, 1979). The sialidoses are distinct from the sialurias in which there is storage and excretion of 'free' sialic acid, rather than 'bound' sialic acid; neuraminidase activity in sialuria is normal or elevated. Salla disease (604369) is a form of 'free' sialic acid disease. Classification Lowden and O'Brien (1979) provided a logical nosology of neuraminidase deficiency into sialidosis type I and type II. Type I is the milder form, also known as the 'normosomatic' type or the cherry red spot-myoclonus syndrome. Sialidosis type II is the more severe form with an earlier onset, and is also known as the 'dysmorphic' type. Type II has been subdivided into juvenile and infantile forms. Other terms for sialidosis type II are mucolipidosis I and lipomucopolysaccharidosis.
Combined deficiency of sialidase AND beta galactosidase
MedGen UID:
82779
Concept ID:
C0268233
Disease or Syndrome
Galactosialidosis is a lysosomal storage disease associated with a combined deficiency of beta-galactosidase (611458) and neuraminidase (608272), secondary to a defect in protective protein/cathepsin A (PPCA). All patients have clinical manifestations typical of a lysosomal disorder, such as coarse facies, cherry red spots, vertebral changes, foam cells in the bone marrow, and vacuolated lymphocytes. Three phenotypic subtypes are recognized. The early infantile form is associated with fetal hydrops, edema, ascites, visceromegaly, skeletal dysplasia, and early death. The late infantile type is characterized by hepatosplenomegaly, growth retardation, cardiac involvement, and rare occurrence of neurologic signs. The juvenile/adult form is characterized by myoclonus, ataxia, angiokeratoma, mental retardation, neurologic deterioration, absence of visceromegaly, and long survival. The majority of reported patients belong to the juvenile/adult group and are mainly of Japanese origin (summary by d'Azzo et al., 2001).
Cytochrome-c oxidase deficiency
MedGen UID:
75662
Concept ID:
C0268237
Congenital Abnormality
Complex IV (cytochrome c oxidase; EC 1.9.3.1) is the terminal enzyme of the respiratory chain and consists of 13 polypeptide subunits, 3 of which are encoded by mitochondrial DNA. The 3 mitochondrially encoded proteins in the cytochrome oxidase complex are the actual catalytic subunits that carry out the electron transport function (Saraste, 1983). See 123995 for discussion of some of the nuclear-encoded subunits. Shoubridge (2001) provided a comprehensive review of cytochrome c oxidase deficiency and noted that most isolated COX deficiencies are inherited as autosomal recessive disorders caused by mutations in nuclear-encoded genes; mutations in the mtDNA-encoded COX subunit genes are relatively rare.
Acute neuronopathic Gaucher's disease
MedGen UID:
78652
Concept ID:
C0268250
Disease or Syndrome
Gaucher disease (GD) encompasses a continuum of clinical findings from a perinatal lethal disorder to an asymptomatic type. The identification of three major clinical types (1, 2, and 3) and two other subtypes (perinatal-lethal and cardiovascular) is useful in determining prognosis and management. GD type 1 is characterized by the presence of clinical or radiographic evidence of bone disease (osteopenia, focal lytic or sclerotic lesions, and osteonecrosis), hepatosplenomegaly, anemia and thrombocytopenia, lung disease, and the absence of primary central nervous system disease. GD types 2 and 3 are characterized by the presence of primary neurologic disease; in the past, they were distinguished by age of onset and rate of disease progression, but these distinctions are not absolute. Disease with onset before age two years, limited psychomotor development, and a rapidly progressive course with death by age two to four years is classified as GD type 2. Individuals with GD type 3 may have onset before age two years, but often have a more slowly progressive course, with survival into the third or fourth decade. The perinatal-lethal form is associated with ichthyosiform or collodion skin abnormalities or with nonimmune hydrops fetalis. The cardiovascular form is characterized by calcification of the aortic and mitral valves, mild splenomegaly, corneal opacities, and supranuclear ophthalmoplegia. Cardiopulmonary complications have been described with all the clinical subtypes, although varying in frequency and severity.
Subacute neuronopathic Gaucher's disease
MedGen UID:
78653
Concept ID:
C0268251
Disease or Syndrome
Gaucher disease (GD) encompasses a continuum of clinical findings from a perinatal lethal disorder to an asymptomatic type. The identification of three major clinical types (1, 2, and 3) and two other subtypes (perinatal-lethal and cardiovascular) is useful in determining prognosis and management. GD type 1 is characterized by the presence of clinical or radiographic evidence of bone disease (osteopenia, focal lytic or sclerotic lesions, and osteonecrosis), hepatosplenomegaly, anemia and thrombocytopenia, lung disease, and the absence of primary central nervous system disease. GD types 2 and 3 are characterized by the presence of primary neurologic disease; in the past, they were distinguished by age of onset and rate of disease progression, but these distinctions are not absolute. Disease with onset before age two years, limited psychomotor development, and a rapidly progressive course with death by age two to four years is classified as GD type 2. Individuals with GD type 3 may have onset before age two years, but often have a more slowly progressive course, with survival into the third or fourth decade. The perinatal-lethal form is associated with ichthyosiform or collodion skin abnormalities or with nonimmune hydrops fetalis. The cardiovascular form is characterized by calcification of the aortic and mitral valves, mild splenomegaly, corneal opacities, and supranuclear ophthalmoplegia. Cardiopulmonary complications have been described with all the clinical subtypes, although varying in frequency and severity.
Sphingolipid activator protein 1 deficiency
MedGen UID:
120624
Concept ID:
C0268262
Disease or Syndrome
Metachromatic leukodystrophy is an inherited disorder characterized by the accumulation of fats called sulfatides in cells. This accumulation especially affects cells in the nervous system that produce myelin, the substance that insulates and protects nerves. Nerve cells covered by myelin make up a tissue called white matter. Sulfatide accumulation in myelin-producing cells causes progressive destruction of white matter (leukodystrophy) throughout the nervous system, including in the brain and spinal cord (the central nervous system) and the nerves connecting the brain and spinal cord to muscles and sensory cells that detect sensations such as touch, pain, heat, and sound (the peripheral nervous system). In people with metachromatic leukodystrophy, white matter damage causes progressive deterioration of intellectual functions and motor skills, such as the ability to walk. Affected individuals also develop loss of sensation in the extremities (peripheral neuropathy), incontinence, seizures, paralysis, an inability to speak, blindness, and hearing loss. Eventually they lose awareness of their surroundings and become unresponsive. While neurological problems are the primary feature of metachromatic leukodystrophy, effects of sulfatide accumulation on other organs and tissues have been reported, most often involving the gallbladder. The most common form of metachromatic leukodystrophy, affecting about 50 to 60 percent of all individuals with this disorder, is called the late infantile form. This form of the disorder usually appears in the second year of life. Affected children lose any speech they have developed, become weak, and develop problems with walking (gait disturbance). As the disorder worsens, muscle tone generally first decreases, and then increases to the point of rigidity. Individuals with the late infantile form of metachromatic leukodystrophy typically do not survive past childhood. In 20 to 30 percent of individuals with metachromatic leukodystrophy, onset occurs between the age of 4 and adolescence. In this juvenile form, the first signs of the disorder may be behavioral problems and increasing difficulty with schoolwork. Progression of the disorder is slower than in the late infantile form, and affected individuals may survive for about 20 years after diagnosis. The adult form of metachromatic leukodystrophy affects approximately 15 to 20 percent of individuals with the disorder. In this form, the first symptoms appear during the teenage years or later. Often behavioral problems such as alcoholism, drug abuse, or difficulties at school or work are the first symptoms to appear. The affected individual may experience psychiatric symptoms such as delusions or hallucinations. People with the adult form of metachromatic leukodystrophy may survive for 20 to 30 years after diagnosis. During this time there may be some periods of relative stability and other periods of more rapid decline. Metachromatic leukodystrophy gets its name from the way cells with an accumulation of sulfatides appear when viewed under a microscope. The sulfatides form granules that are described as metachromatic, which means they pick up color differently than surrounding cellular material when stained for examination.
Multiple sulfatase deficiency
MedGen UID:
75664
Concept ID:
C0268263
Disease or Syndrome
Multiple sulfatase deficiency is an autosomal recessive inborn error of metabolism resulting in tissue accumulation of sulfatides, sulfated glycosaminoglycans, sphingolipids, and steroid sulfates. The enzymatic defect affects the whole family of sulfatase enzymes; thus, the disorder combines features of metachromatic leukodystrophy (250100) and of various mucopolysaccharidoses (see, e.g., MPS6; 253200). Affected individuals show neurologic deterioration with mental retardation, skeletal anomalies, organomegaly, and ichthyosis. Different types of MSD can be distinguished according to the age of onset: neonatal, late infantile (0 to 2 years), and juvenile (2 to 4 years). Neonatal MSD is the most severe form with a broad range of mucopolysaccharidosis-like symptoms and death within the first year of life. Late-infantile MSD, which includes the majority of cases, resembles late-infantile metachromatic leukodystrophy with progressive loss of mental and motor abilities and skeletal changes. There is also an attenuated form of late-infantile MSD with onset beyond the second year of life. Rare cases of juvenile-onset MSD have been reported with onset of symptoms in late childhood and slower progression (Blanco-Aguirre et al., 2001) (summary by Schlotawa et al., 2011).
Tay-Sachs disease, variant AB
MedGen UID:
78657
Concept ID:
C0268275
Disease or Syndrome
The GM2-gangliosidoses are a group of disorders caused by excessive accumulation of ganglioside GM2 and related glycolipids in the lysosomes, mainly of neuronal cells. GM2-gangliosidosis AB variant is characterized by normal hexosaminidase A (HEXA; 606869) and hexosaminidase B (HEXB; 606873) but the inability to form a functional GM2 activator complex. The clinical and biochemical phenotype of the AB variant is very similar to that of classic Tay-Sachs disease (see 272800) (Gravel et al., 2001).
Cutis laxa-corneal clouding-oligophrenia syndrome
MedGen UID:
82794
Concept ID:
C0268354
Congenital Abnormality
De Barsy syndrome, or autosomal recessive cutis laxa type III (ARCL3), is characterized by cutis laxa, a progeria-like appearance, and ophthalmologic abnormalities (summary by Kivuva et al., 2008). Genetic Heterogeneity of De Barsy Syndrome Autosomal recessive cutis laxa type IIIA (ARCL3A) is caused by mutation in the ALDH18A1 gene. ARCL3B is caused by mutation in the PYCR1 gene (179035). For a phenotypic description and a discussion of genetic heterogeneity of autosomal recessive cutis laxa, see 219200.
Cutis laxa with osteodystrophy
MedGen UID:
82795
Concept ID:
C0268355
Disease or Syndrome
ATP6V0A2-related cutis laxa, also known as autosomal recessive cutis laxa type 2A (ARCL2A), spans a phenotypic spectrum that includes Debré-type cutis laxa at the severe end and wrinkly skin syndrome at the mild end. Affected individuals have furrowing of the skin of the whole body that improves with time. They may have other evidence of a generalized connective disorder, including enlarged anterior fontanelle in infancy, congenital dislocation of the hips, inguinal hernias, and high myopia. In most (not all) affected individuals, cortical and cerebellar malformations are present and are associated with severe developmental delays, seizures, and neurologic regression.
Infantile hypophosphatasia
MedGen UID:
75677
Concept ID:
C0268412
Disease or Syndrome
Hypophosphatasia is characterized by defective mineralization of bone and/or teeth in the presence of low activity of serum and bone alkaline phosphatase. Clinical features range from stillbirth without mineralized bone at the severe end to pathologic fractures of the lower extremities in later adulthood at the mild end. At least six clinical forms are currently recognized based on age at diagnosis and severity of features: Perinatal (lethal) hypophosphatasia characterized by respiratory insufficiency and hypercalcemia. Perinatal (benign) hypophosphatasia with prenatal skeletal manifestations that slowly resolve into the milder childhood or adult form. Infantile hypophosphatasia with onset between birth and age six months of rickets without elevated serum alkaline phosphatase activity. Childhood hypophosphatasia that ranges from low bone mineral density for age with unexplained fractures to rickets. Adult hypophosphatasia characterized by early loss of adult dentition and stress fractures and pseudofractures of the lower extremities in middle age. Odontohypophosphatasia characterized by premature exfoliation of primary teeth and/or severe dental caries as an isolated finding or as part of the above forms of hypophosphatasia.
Deficiency of glycerol kinase
MedGen UID:
82803
Concept ID:
C0268418
Disease or Syndrome
Francke et al. (1987) noted that there are 3 clinically distinct forms of glycerol kinase deficiency: infantile, juvenile, and adult. The infantile form is associated with severe developmental delay, and those with the adult form have no symptoms and are often detected fortuitously. The infantile form of GK deficiency, or the 'GK complex,' results from the Xp21 contiguous gene deletion syndrome (300679) with congenital adrenal hypoplasia (300200) and/or Duchenne muscular dystrophy (DMD; 310200), whereas the juvenile and adult forms have isolated GK deficiency (Walker et al., 1996).
Alstrom syndrome
MedGen UID:
78675
Concept ID:
C0268425
Congenital Abnormality
Alström syndrome is characterized by cone-rod dystrophy, obesity, progressive sensorineural hearing impairment, dilated or restrictive cardiomyopathy, the insulin resistance syndrome, and multiple organ failure. Wide clinical variability is observed among affected individuals, even within the same family. Cone-rod dystrophy presents as progressive visual impairment, photophobia, and nystagmus usually starting between birth and age 15 months. Many individuals lose all perception of light by the end of the second decade, but a minority retain the ability to read large print into the third decade. Children usually have normal birth weight but develop truncal obesity during their first year. Progressive sensorineural hearing loss presents in the first decade in as many as 70% of individuals. Hearing loss may progress to the severe or moderately severe range (40-70 db) by the end of the first to second decade. Insulin resistance is typically accompanied by the skin changes of acanthosis nigricans, and proceeds to type 2 diabetes in the majority by the third decade. Nearly all demonstrate associated dyslipidemia. Other endocrine abnormalities can include hypothyroidism, hypogonadotropic hypogonadism in boys, and polycystic ovaries in girls. More than 60% of individuals with Alström syndrome develop cardiac failure as a result of dilated or restrictive cardiomyopathy. About 50% of individuals have delay in early developmental milestones; intelligence is normal. Liver involvement includes elevation of transaminases, steatosis, hepatosplenomegaly, and steatohepatitis. Portal hypertension and cirrhosis can lead to hepatic encephalopathy and life-threatening esophageal varices. Pulmonary dysfunction and severe renal disease may also develop. End-stage renal disease (ESRD) can occur as early as the late teens.
Primary hypomagnesemia
MedGen UID:
120640
Concept ID:
C0268448
Disease or Syndrome
Familial hypomagnesemia with hypercalciuria and nephrocalcinosis is a progressive renal disorder characterized by excessive urinary Ca(2+) and Mg(2+) excretion. There is progressive loss of kidney function, and in about 50% of cases, the need for renal replacement therapy arises as early as the second decade of life (summary by Muller et al., 2006). A similar disorder with renal magnesium wasting, renal failure, and nephrocalcinosis (HOMG5; 248190) is caused by mutations in another tight-junction gene, CLDN19 (610036), and is distinguished by the association of severe ocular involvement. For a discussion of phenotypic and genetic heterogeneity of familial hypomagnesemia, see HOMG1 (602014).
Familial hypokalemia-hypomagnesemia
MedGen UID:
75681
Concept ID:
C0268450
Disease or Syndrome
Gitelman syndrome is an autosomal recessive renal tubular salt-wasting disorder characterized by hypokalemic metabolic alkalosis with hypomagnesemia and hypocalciuria. It is the most common renal tubular disorder among Caucasians (prevalence of 1 in 40,000). Most patients have onset of symptoms as adults, but some can present in childhood. Clinical features include transient periods of muscle weakness and tetany, abdominal pains, and chondrocalcinosis (summary by Glaudemans et al., 2012). For a complete description of Bartter syndrome and a discussion of related disorders, see 607364. See also pseudoaldosteronism (177200).
Dihydropteridine reductase deficiency
MedGen UID:
75682
Concept ID:
C0268465
Disease or Syndrome
Tetrahydrobiopterin deficiency is a rare disorder characterized by a shortage (deficiency) of a molecule called tetrahydrobiopterin or BH4. This condition alters the levels of several substances in the body, including phenylalanine. Phenylalanine is a building block of proteins (an amino acid) that is obtained through the diet. It is found in foods that contain protein and in some artificial sweeteners. High levels of phenylalanine are present from early infancy in people with untreated tetrahydrobiopterin deficiency. This condition also alters the levels of chemicals called neurotransmitters, which transmit signals between nerve cells in the brain. Infants with tetrahydrobiopterin deficiency appear normal at birth, but medical problems ranging from mild to severe become apparent over time. Signs and symptoms of this condition can include intellectual disability, progressive problems with development, movement disorders, difficulty swallowing, seizures, behavioral problems, and an inability to control body temperature.
GTP cyclohydrolase I deficiency
MedGen UID:
75683
Concept ID:
C0268467
Disease or Syndrome
Tetrahydrobiopterin deficiency is a rare disorder characterized by a shortage (deficiency) of a molecule called tetrahydrobiopterin or BH4. This condition alters the levels of several substances in the body, including phenylalanine. Phenylalanine is a building block of proteins (an amino acid) that is obtained through the diet. It is found in foods that contain protein and in some artificial sweeteners. High levels of phenylalanine are present from early infancy in people with untreated tetrahydrobiopterin deficiency. This condition also alters the levels of chemicals called neurotransmitters, which transmit signals between nerve cells in the brain. Infants with tetrahydrobiopterin deficiency appear normal at birth, but medical problems ranging from mild to severe become apparent over time. Signs and symptoms of this condition can include intellectual disability, progressive problems with development, movement disorders, difficulty swallowing, seizures, behavioral problems, and an inability to control body temperature.
Sepiapterin reductase deficiency
MedGen UID:
120642
Concept ID:
C0268468
Disease or Syndrome
SPR deficiency results in neurologic deterioration due to severe dopamine and serotonin deficiencies in the central nervous system caused by a defect in BH4 synthesis. Clinically, affected individuals show an L-DOPA-responsive, diurnally fluctuating movement disorder usually associated with cognitive delay and severe neurologic dysfunction. BH4 is a required cofactor for the synthesis of the neurotransmitters dopamine and serotonin. BH4 is also a required cofactor for phenylalanine hydroxylase (PAH; 612349), but patients with SPR deficiency do not exhibit overt hyperphenylalaninemia. The lack of hyperphenylalaninemia distinguishes SPR deficiency from other disorders of BH4 synthesis (see, e.g., HPABH4A, 261640). However, the neurologic phenotype of SPR deficiency resembles the other BH4-deficient disorders (summary by Bonafe et al., 2001 and Friedman et al., 2012). Another form of dopa-responsive dystonia (DTY5; 128230) is caused by mutation in the gene encoding GTP cyclohydrolase I (GCH1; 600225), which is also a component of the biopterin synthetic pathway.
Tyrosinemia type 2
MedGen UID:
75687
Concept ID:
C0268487
Disease or Syndrome
Tyrosinemia type II is an autosomal recessive disorder characterized by keratitis, painful palmoplantar hyperkeratosis, mental retardation, and elevated serum tyrosine levels. The disorder is caused by deficiency of hepatic tyrosine aminotransferase (Natt et al., 1992).
Proline dehydrogenase deficiency
MedGen UID:
120645
Concept ID:
C0268529
Disease or Syndrome
Phang et al. (2001) noted that prospective studies of HPI probands identified through newborn screening as well as reports of several families have suggested that it is a metabolic disorder not clearly associated with clinical manifestations. Phang et al. (2001) concluded that HPI is a relatively benign condition in most individuals under most circumstances. However, other reports have suggested that some patients have a severe phenotype with neurologic manifestations, including epilepsy and mental retardation (Jacquet et al., 2003). Genetic Heterogeneity of Hyperprolinemia See also hyperprolinemia type II (HYRPRO2; 239510), which is caused by mutation in the gene encoding pyrroline-5-carboxylate dehydrogenase (P5CDH, ALDH4A1; 606811) on chromosome 1p36.
Ornithine carbamoyltransferase deficiency
MedGen UID:
75692
Concept ID:
C0268542
Disease or Syndrome
Ornithine transcarbamylase (OTC) deficiency can occur as a severe neonatal-onset disease in males (but rarely in females) and as a late-onset (partial) disease in males and females. Males with severe neonatal-onset OTC deficiency are typically normal at birth but become symptomatic from hyperammonemia on day two to three of life and are usually catastrophically ill by the time they come to medical attention. After successful treatment of neonatal hyperammonemic coma these infants can easily become hyperammonemic again despite appropriate treatment; they typically require liver transplant by age six months to improve quality of life. Males and heterozygous females with late-onset (partial) OTC deficiency can present from infancy to later childhood, adolescence, or adulthood. No matter how mild the disease, a hyperammonemic crisis can be precipitated by stressors and become a life-threatening event at any age and in any situation in life. For all individuals with OTC deficiency, typical neuropsychological complications include developmental delay, learning disabilities, intellectual disability, attention deficit hyperactivity disorder (ADHD), and executive function deficits.
Hyperammonemia, type III
MedGen UID:
120649
Concept ID:
C0268543
Disease or Syndrome
N-acetylglutamate synthase deficiency is an autosomal recessive disorder of the urea cycle. The clinical and biochemical features of the disorder are indistinguishable from carbamoyl phosphate synthase I deficiency (237300), since the CPS1 enzyme (608307) has an absolute requirement for NAGS (Caldovic et al., 2007).
Argininosuccinate lyase deficiency
MedGen UID:
78687
Concept ID:
C0268547
Disease or Syndrome
Deficiency of argininosuccinate lyase (ASL), the enzyme that cleaves argininosuccinic acid to produce arginine and fumarate in the fourth step of the urea cycle, is characterized by a severe neonatal onset form and a late onset form. The severe neonatal onset form, which is indistinguishable from that of other urea cycle disorders, is characterized by hyperammonemia within the first few days after birth accompanied by vomiting, lethargy, hypothermia, and poor feeding. In the absence of treatment, lethargy, seizures, and coma worsen, resulting in death. In contrast, the late onset form ranges from episodic hyperammonemia triggered by acute infection or stress to cognitive impairment, behavioral abnormalities, and/or learning disabilities in the absence of any documented episodes of hyperammonemia. Manifestations of ASL deficiency that appear to be unrelated to the severity or duration of hyperammonemic episodes include: (1) neurocognitive deficiencies (attention deficit hyperactivity disorder [ADHD], developmental disability, seizures, and learning disability); (2) liver disease (hepatitis, cirrhosis); (3) trichorrhexis nodosa (coarse brittle hair that breaks easily); and (4) systemic hypertension.
Arginase deficiency
MedGen UID:
78688
Concept ID:
C0268548
Disease or Syndrome
Arginase deficiency in untreated individuals is characterized by episodic hyperammonemia of variable degree that is infrequently severe enough to be life threatening or to cause death. Most commonly, birth and early childhood are normal. Untreated individuals have slowing of linear growth at age one to three years, followed by development of spasticity, plateauing of cognitive development, and subsequent loss of developmental milestones. If untreated, arginase deficiency usually progresses to severe spasticity, loss of ambulation, complete loss of bowel and bladder control, and severe intellectual disability. Seizures are common and are usually controlled easily.
Hyperlysinemia
MedGen UID:
82816
Concept ID:
C0268553
Disease or Syndrome
Hyperlysinemia type I is an autosomal recessive metabolic condition with variable clinical features. Some patients who present in infancy with nonspecific seizures, hypotonia, or mildly delayed psychomotor development have been found to have increased serum lysine and pipecolic acid on laboratory analysis. However, about 50% of probands are reported to be asymptomatic, and hyperlysinemia is generally considered to be a benign metabolic variant (summary by Tondo et al., 2013; Houten et al., 2013). The AASS gene encodes a bifunctional enzyme: lysine alpha-ketoglutarate reductase and saccharopine dehydrogenase. In hyperlysinemia type I, both enzymatic functions of AASS are defective; in hyperlysinemia type II, also known as saccharopinuria (268700), some of the first enzymatic function is retained (Cox, 1985; Cox et al., 1985).
Hyperleucine-isoleucinemia
MedGen UID:
82821
Concept ID:
C0268574
Congenital Abnormality
Isovaleryl-CoA dehydrogenase deficiency
MedGen UID:
82822
Concept ID:
C0268575
Disease or Syndrome
The term "organic acidemia" or "organic aciduria" (OA) applies to a group of disorders characterized by the excretion of non-amino organic acids in urine. Most organic acidemias result from dysfunction of a specific step in amino acid catabolism, usually the result of deficient enzyme activity. The majority of the classic organic acid disorders are caused by abnormal amino acid catabolism of branched-chain amino acids or lysine. They include maple syrup urine disease (MSUD), propionic acidemia, methylmalonic acidemia (MMA), methylmalonic aciduria and homocystinuria, isovaleric acidemia, biotin-unresponsive 3-methylcrotonyl-CoA carboxylase deficiency, 3-hydroxy-3-methylglutaryl-CoA (HMG-CoA) lyase deficiency, ketothiolase deficiency, and glutaricacidemia type I (GA I). A neonate affected with an OA is usually well at birth and for the first few days of life. The usual clinical presentation is that of toxic encephalopathy and includes vomiting, poor feeding, neurologic symptoms such as seizures and abnormal tone, and lethargy progressing to coma. Outcome is enhanced by diagnosis and treatment in the first ten days of life. In the older child or adolescent, variant forms of the OAs can present as loss of intellectual function, ataxia or other focal neurologic signs, Reye syndrome, recurrent ketoacidosis, or psychiatric symptoms.
Propionic acidemia
MedGen UID:
75694
Concept ID:
C0268579
Disease or Syndrome
The spectrum of propionic acidemia (PA) ranges from neonatal-onset to late-onset disease. Neonatal-onset PA, the most common form, is characterized by poor feeding, vomiting, and somnolence in the first days of life in a previously healthy infant, followed by lethargy, seizures, coma, and death. It is frequently accompanied by metabolic acidosis with anion gap, ketonuria, hypoglycemia, hyperammonemia, and cytopenias. Late-onset PA includes developmental regression, chronic vomiting, protein intolerance, failure to thrive, hypotonia, and occasionally basal ganglia infarction (resulting in dystonia and choreoathetosis) and cardiomyopathy. Affected children can have an acute decompensation that resembles the neonatal presentation and is precipitated by a catabolic stress such as infection, injury, or surgery. Isolated cardiomyopathy and arrhythmia can be observed on rare occasion in the absence of clinical metabolic decompensation or neurocognitive deficits. Manifestations of neonatal and late-onset PA over time can include growth impairment, intellectual disability, seizures, basal ganglia lesions, pancreatitis, and cardiomyopathy. Other rarely reported complications include optic atrophy, hearing loss, premature ovarian insufficiency (POI), and chronic renal failure.
Holocarboxylase synthetase deficiency
MedGen UID:
120653
Concept ID:
C0268581
Disease or Syndrome
Holocarboxylase synthetase deficiency, a biotin-responsive multiple carboxylase deficiency (MCD), is characterized by metabolic acidosis, lethargy, hypotonia, convulsions, and dermatitis. Most patients present in the newborn or early infantile period, but some become symptomatic in the later infantile period (summary by Suzuki et al., 2005). Also see biotinidase deficiency (253260), another form of MCD with a later onset. Care must be taken to differentiate the inherited multiple carboxylase deficiencies from acquired biotin deficiencies, such as those that develop after excessive dietary intake of avidin, an egg-white glycoprotein that binds specifically and essentially irreversibly to biotin (Sweetman et al., 1981) or prolonged parenteral alimentation without supplemental biotin (Mock et al., 1981).
Glutaric aciduria, type 1
MedGen UID:
124337
Concept ID:
C0268595
Disease or Syndrome
The term "organic acidemia" or "organic aciduria" (OA) applies to a group of disorders characterized by the excretion of non-amino organic acids in urine. Most organic acidemias result from dysfunction of a specific step in amino acid catabolism, usually the result of deficient enzyme activity. The majority of the classic organic acid disorders are caused by abnormal amino acid catabolism of branched-chain amino acids or lysine. They include maple syrup urine disease (MSUD), propionic acidemia, methylmalonic acidemia (MMA), methylmalonic aciduria and homocystinuria, isovaleric acidemia, biotin-unresponsive 3-methylcrotonyl-CoA carboxylase deficiency, 3-hydroxy-3-methylglutaryl-CoA (HMG-CoA) lyase deficiency, ketothiolase deficiency, and glutaricacidemia type I (GA I). A neonate affected with an OA is usually well at birth and for the first few days of life. The usual clinical presentation is that of toxic encephalopathy and includes vomiting, poor feeding, neurologic symptoms such as seizures and abnormal tone, and lethargy progressing to coma. Outcome is enhanced by diagnosis and treatment in the first ten days of life. In the older child or adolescent, variant forms of the OAs can present as loss of intellectual function, ataxia or other focal neurologic signs, Reye syndrome, recurrent ketoacidosis, or psychiatric symptoms.
Methylcrotonyl-CoA carboxylase deficiency
MedGen UID:
78691
Concept ID:
C0268600
Disease or Syndrome
The term "organic acidemia" or "organic aciduria" (OA) applies to a group of disorders characterized by the excretion of non-amino organic acids in urine. Most organic acidemias result from dysfunction of a specific step in amino acid catabolism, usually the result of deficient enzyme activity. The majority of the classic organic acid disorders are caused by abnormal amino acid catabolism of branched-chain amino acids or lysine. They include maple syrup urine disease (MSUD), propionic acidemia, methylmalonic acidemia (MMA), methylmalonic aciduria and homocystinuria, isovaleric acidemia, biotin-unresponsive 3-methylcrotonyl-CoA carboxylase deficiency, 3-hydroxy-3-methylglutaryl-CoA (HMG-CoA) lyase deficiency, ketothiolase deficiency, and glutaricacidemia type I (GA I). A neonate affected with an OA is usually well at birth and for the first few days of life. The usual clinical presentation is that of toxic encephalopathy and includes vomiting, poor feeding, neurologic symptoms such as seizures and abnormal tone, and lethargy progressing to coma. Outcome is enhanced by diagnosis and treatment in the first ten days of life. In the older child or adolescent, variant forms of the OAs can present as loss of intellectual function, ataxia or other focal neurologic signs, Reye syndrome, recurrent ketoacidosis, or psychiatric symptoms.
Familial methionine malabsorption
MedGen UID:
78693
Concept ID:
C0268622
Disease or Syndrome
4-Hydroxyphenylpyruvate dioxygenase deficiency
MedGen UID:
78694
Concept ID:
C0268623
Disease or Syndrome
Tyrosinemia type III is an autosomal recessive disorder caused by a deficiency in the activity of 4-hydroxyphenylpyruvate dioxygenase (HPD) and is characterized by elevated levels of blood tyrosine and massive excretion of its derivatives into urine. Patients with this disorder have mild mental retardation and/or convulsions, with the absence of liver damage (summary by Tomoeda et al., 2000).
Sulfite oxidase deficiency
MedGen UID:
78695
Concept ID:
C0268624
Disease or Syndrome
Hyper-beta-alaninemia
MedGen UID:
75702
Concept ID:
C0268630
Disease or Syndrome
Succinate-semialdehyde dehydrogenase deficiency
MedGen UID:
124340
Concept ID:
C0268631
Disease or Syndrome
Succinic semialdehyde dehydrogenase (SSADH) deficiency is characterized by psychomotor retardation, childhood-onset hypotonia, and ataxia. Seizures occur in more than 50% of affected individuals. Hyperkinetic behavior, aggression, self-injurious behaviors, hallucinations, and sleep disturbances have been reported in nearly half of all patients, and are common in older individuals. Basal ganglia signs such as choreoathetosis, dystonia, and myoclonus have been reported in a few individuals with earlier-onset, more severe disease. Involvement beyond the central nervous system has not been described.
Infantile neuroaxonal dystrophy
MedGen UID:
82852
Concept ID:
C0270724
Disease or Syndrome
PLA2G6-associated neurodegeneration (PLAN) comprises a continuum of three phenotypes with overlapping clinical and radiologic features: Classic infantile neuroaxonal dystrophy (INAD). Atypical neuroaxonal dystrophy (atypical NAD). PLA2G6-related dystonia-parkinsonism. INAD usually begins between ages six months and three years with developmental regression, hypotonia, progressive psychomotor delay, and progressive spastic tetraparesis. Strabismus, nystagmus, and optic atrophy are common. Disease progression is rapid. Many affected children never learn to walk or lose the ability shortly after attaining it. Severe spasticity, progressive cognitive decline, and visual impairment typically result in death during the first decade. Atypical NAD shows more phenotypic variability than INAD. In general, onset is in early childhood but can be as late as the end of the second decade. The presenting signs may be gait instability or ataxia (as in the classic form) or speech delay and autistic features, which are sometimes the only evidence of disease for a year or more. The course is fairly stable during early childhood and resembles static encephalopathy but is followed by neurologic deterioration between ages seven and 12 years. PLA2G6-related dystonia-parkinsonism presents with subacute onset of dystonia-parkinsonism in late adolescence/early adulthood. Other findings are eye movement abnormalities, pyramidal tract signs, and marked cognitive decline.
Alexander's disease
MedGen UID:
78724
Concept ID:
C0270726
Disease or Syndrome
Alexander disease is a progressive disorder of cerebral white matter that predominantly affects infants and children and has variable life expectancy. The later-onset forms present with a slower clinical course. The infantile form comprises about 42% of affected individuals, the juvenile form about 22%, and the adult form about 33%. A neonatal form is also recognized. The neonatal form leads to severe disability or death within two years. Characteristics include seizures, hydrocephalus, severe motor and intellectual disability, and elevated CSF protein concentration. MRI shows severe white matter abnormalities with involvement of the basal ganglia and cerebellum. The infantile form presents in the first two years of life, typically with progressive psychomotor retardation with loss of developmental milestones, megalencephaly, frontal bossing, and seizures. Other findings include hyperreflexia and pyramidal signs, ataxia, and occasional hydrocephalus secondary to aqueductal stenosis. Affected children survive weeks to several years. The juvenile form usually presents between ages four and ten years, occasionally in the mid-teens. Findings can include bulbar/pseudobulbar signs, ataxia, gradual loss of intellectual function, seizures, normocephaly or megalencephaly, and breathing problems. Survival ranges from the early teens to the 20s-30s. The adult form is the most variable.
De Lange syndrome
MedGen UID:
78752
Concept ID:
C0270972
Congenital Abnormality
Classic Cornelia de Lange syndrome (CdLS) is characterized by distinctive facial features, growth retardation (prenatal onset; <5th centile throughout life), hirsutism, and upper limb reduction defects that range from subtle phalangeal abnormalities to oligodactyly (missing digits). Craniofacial features include synophrys, arched eyebrows, long eyelashes, small upturned nose, small widely spaced teeth, and microcephaly. IQ ranges from below 30 to 102 (mean: 53). Many individuals demonstrate autistic and self-destructive tendencies. Frequent findings include cardiac septal defects, gastrointestinal dysfunction, hearing loss, myopia, and cryptorchidism or hypoplastic genitalia. Individuals with a milder phenotype have less severe growth, cognitive, and limb involvement, but often have facial features consistent with CdLS.
Familial hemophagocytic lymphohistiocytosis
MedGen UID:
78797
Concept ID:
C0272199
Pathologic Function
Familial hemophagocytic lymphohistiocytosis (FHL) is characterized by proliferation and infiltration of hyperactivated macrophages and T-lymphocytes manifesting as acute illness with prolonged fever, cytopenias, and hepatosplenomegaly. Onset is typically within the first months or years of life and, on occasion, in utero, although later childhood or adult onset is more common than previously suspected. Neurologic abnormalities may be present initially or may develop later; they may include increased intracranial pressure, irritability, neck stiffness, hypotonia, hypertonia, convulsions, cranial nerve palsies, ataxia, hemiplegia, quadriplegia, blindness, and coma. Rash and lymphadenopathy are less common. Other findings include liver dysfunction and bone marrow hemophagocytosis. The median survival of children with typical FHL, without treatment, is less than two months; progression of hemophagocytic lymphohistiocytosis and infection account for the majority of deaths in untreated individuals.
Reading seizure
MedGen UID:
75817
Concept ID:
C0278193
Disease or Syndrome
Cronkhite-Canada syndrome
MedGen UID:
129128
Concept ID:
C0282207
Disease or Syndrome
Cronkhite-Canada syndrome is characterized by gastrointestinal hamartomatous polyposis, alopecia, onychodystrophy, skin hyperpigmentation, and diarrhea. It is associated with high morbidity (summary by Sweetser et al., 2012).
Idiopathic livedo reticularis with systemic involvement
MedGen UID:
76449
Concept ID:
C0282492
Disease or Syndrome
Sneddon syndrome is a noninflammatory arteriopathy characterized by onset of livedo reticularis in the second decade and onset of cerebrovascular disease in early adulthood (summary by Bras et al., 2014). Livedo reticularis occurs also with polyarteritis nodosa, systemic lupus erythematosus, and central thrombocythemia, any one of which may be accompanied by cerebrovascular accidents (Bruyn et al., 1987).
Neonatal adrenoleucodystrophy
MedGen UID:
129184
Concept ID:
C0282525
Disease or Syndrome
Peroxisome biogenesis disorders, Zellweger syndrome spectrum (PBD, ZSS) is a continuum of three phenotypes — Zellweger syndrome (ZS), the most severe; neonatal adrenoleukodystrophy (NALD); and infantile Refsum disease (IRD), the least severe — that were originally described before the biochemical and molecular bases of these disorders had been fully determined. Individuals with PBD, ZSS usually come to clinical attention in the newborn period or later in childhood. In the newborn period, affected children are hypotonic, feed poorly, and have distinctive facies, seizures, and liver cysts with hepatic dysfunction. Bony stippling (chondrodysplasia punctata) of the patella(e) and other long bones may occur. Infants with ZS are significantly impaired and typically die during the first year of life, usually having made no developmental progress. Older children have retinal dystrophy, sensorineural hearing loss, developmental delay with hypotonia, and liver dysfunction. The clinical courses of NALD and IRD are variable and may include developmental delays, hearing loss, vision impairment, liver dysfunction, episodes of hemorrhage, and intracranial bleeding. While some children can be very hypotonic, others learn to walk and talk. The condition is often slowly progressive.
Septo-optic dysplasia sequence
MedGen UID:
90926
Concept ID:
C0338503
Congenital Abnormality
Septooptic dysplasia is a clinically heterogeneous disorder loosely defined by any combination of optic nerve hypoplasia, pituitary gland hypoplasia, and midline abnormalities of the brain, including absence of the corpus callosum and septum pellucidum (Dattani et al., 1998). The diagnosis of this rare congenital anomaly is made when 2 or more features of the classic triad are present. Approximately 30% of patients have complete manifestations, 62% display hypopituitarism, and 60% have an absent septum pellucidum. The disorder is equally prevalent in males and females and is more common in infants born to younger mothers, with a reported incidence of 1 in 10,000 live births (summary by Webb and Dattani, 2010). Also see 516020.0012 for a form of septooptic dysplasia associated with cardiomyopathy and exercise intolerance.
Capillary malformations, congenital, 1
MedGen UID:
90955
Concept ID:
C0340803
Congenital Abnormality
Capillary malformations are a form of vascular malformation that are present from birth, tend to grow with the individual, do not regress spontaneously, and show normal rates of endothelial cell turnover. Capillary malformations are distinct from capillary hemangiomas (602089), which are highly proliferative lesions that appear shortly after birth and show rapid growth, slow involution, and endothelial hypercellularity (Spring and Bentz, 2005; Legiehn and Heran, 2006).
Hennekam lymphangiectasia-lymphedema syndrome
MedGen UID:
137946
Concept ID:
C0340834
Congenital Abnormality
Hennekam lymphangiectasia-lymphedema syndrome is an autosomal recessive disorder characterized by generalized lymphatic dysplasia affecting various organs, including the intestinal tract, pericardium, and limbs. Additional features of the disorder include facial dysmorphism and cognitive impairment (summary by Alders et al., 2014). Genetic Heterogeneity of Hennekam Lymphangiectasia-Lymphedema Syndrome See also HKLLS2 (616006), caused by mutation in the FAT4 gene (612411) on chromosome 4q28.
Visceral steatosis
MedGen UID:
90962
Concept ID:
C0341447
Pathologic Function
Bird-headed dwarfism with progressive ataxia, insulin-resistant diabetes, goiter, and primary gonadal insufficiency
MedGen UID:
90978
Concept ID:
C0342284
Congenital Abnormality
Megaloblastic anemia, thiamine-responsive, with diabetes mellitus and sensorineural deafness
MedGen UID:
83338
Concept ID:
C0342287
Congenital Abnormality
Thiamine-responsive megaloblastic anemia syndrome (TRMA) is characterized by megaloblastic anemia, sensorineural hearing loss, and diabetes mellitus. Onset of megaloblastic anemia is between infancy and adolescence. The anemia is corrected with pharmacologic doses of thiamine (vitamin B1) (25-75 mg/day compared to US RDA of 1.5 mg/day). However, the red cells remain macrocytic. The anemia can recur when thiamine is withdrawn. Progressive sensorineural hearing loss has generally been early and can be detected in toddlers; hearing loss is irreversible and may not be prevented by thiamine treatment. The diabetes mellitus is non-type I in nature, with age of onset from infancy to adolescence.
Diabetes-deafness syndrome maternally transmitted
MedGen UID:
90979
Concept ID:
C0342289
Congenital Abnormality
Maternally inherited diabetes-deafness syndrome (MIDD) is a mitochondrial disorder characterized by onset of sensorineural hearing loss and diabetes in adulthood. Some patients may have additional features observed in mitochondrial disorders, including pigmentary retinopathy, ptosis, cardiomyopathy, myopathy, renal problems, and neuropsychiatric symptoms (Ballinger et al., 1992; Reardon et al., 1992; Guillausseau et al., 2001). The association of diabetes and deafness is observed with Wolfram syndrome (see 222300), Rogers syndrome (249270), and Herrmann syndrome (172500), but all 3 of these disorders have other clinical manifestations.
Hypoparathyroidism - X-linked
MedGen UID:
87437
Concept ID:
C0342344
Congenital Abnormality
Hypocalcemia, autosomal dominant 1
MedGen UID:
87438
Concept ID:
C0342345
Congenital Abnormality
Autosomal dominant hypocalcemia-1 is associated with low or normal serum parathyroid hormone concentrations (PTH). Approximately 50% of patients have mild or asymptomatic hypocalcemia; about 50% have paresthesias, carpopedal spasm, and seizures; about 10% have hypercalciuria with nephrocalcinosis or kidney stones; and more than 35% have ectopic and basal ganglia calcifications (summary by Nesbit et al., 2013). Thakker (2001) noted that patients with gain-of-function mutations in the CASR gene, resulting in generally asymptomatic hypocalcemia with hypercalciuria, have low-normal serum PTH concentrations and have often been diagnosed with hypoparathyroidism because of the insensitivity of earlier PTH assays. Because treatment with vitamin D to correct the hypocalcemia in these patients causes hypercalciuria, nephrocalcinosis, and renal impairment, these patients need to be distinguished from those with other forms of hypoparathyroidism (see 146200). Thakker (2001) suggested the designation 'autosomal dominant hypocalcemic hypercalciuria' for this CASR-related disorder. Genetic Heterogeneity of Autosomal Dominant Hypocalcemia Autosomal dominant hypocalcemia-2 (HYPOC2; 615361) is caused by mutation in the GNA11 gene (139313) on chromosome 19p13.
Autosomal dominant hypophosphatemic rickets
MedGen UID:
83346
Concept ID:
C0342642
Congenital Abnormality
Autosomal dominant hypophosphatemic rickets is characterized by isolated renal phosphate wasting, hypophosphatemia, and inappropriately normal 1,25-dihydroxyvitamin D3 (calcitriol) levels. Patients frequently present with bone pain, rickets, and tooth abscesses. In contrast to X-linked dominant hypophosphatemic rickets (XLH; 307800), ADHR shows incomplete penetrance, variable age at onset (childhood to adult), and resolution of the phosphate-wasting defect in rare cases (Econs et al., 1997). See also hypophosphatemic bone disease (146350). Genetic Heterogeneity of Hypophosphatemic Rickets Other forms of hypophosphatemic rickets include an autosomal recessive forms, i.e., ARHR1 (241520), caused by mutation in the DMP1 gene (600980) on chromosome 4q21, and ARHR2 (613312), caused by mutation in the ENPP1 gene (173335) on chromosome 6q22-q23. An X-linked dominant form (307800) is caused by mutation in the PHEX gene (300550), and an X-linked recessive form (300554) is caused by mutation in the CLCN5 gene (300008). Clinical Variability of Hypophosphatemic Rickets Hypophosphatemic rickets can be caused by disorders of vitamin D metabolism or action (see VDDR1A, 264700). A form of hypophosphatemic rickets with hypercalciuria (HHRH; 241530) is caused by mutation in the SLC34A3 gene (609826), and there is evidence that a form of hypophosphatemic rickets with hyperparathyroidism (612089) may be caused by a translocation that results in an increase in alpha-klotho levels (KLOTHO; 604824).
Congenital defect of folate absorption
MedGen UID:
83348
Concept ID:
C0342705
Disease or Syndrome
Hereditary folate malabsorption (HFM) is characterized by folate deficiency with impaired intestinal folate absorption and impaired folate transport into the central nervous system (CNS). Findings include poor feeding and failure to thrive, anemia often accompanied by leukopenia and/or thrombocytopenia, diarrhea and/or oral mucositis, hypoimmunoglobulinemia, and other immunologic dysfunction resulting in infections with unusual organisms. Neurologic manifestations include developmental delays, cognitive and motor impairment, behavioral disorders and, frequently, seizures.
Gamma-aminobutyric acid transaminase deficiency
MedGen UID:
137977
Concept ID:
C0342708
Disease or Syndrome
3-Methylglutaconic aciduria
MedGen UID:
90994
Concept ID:
C0342727
Disease or Syndrome
3-methylglutaconyl-CoA hydratase deficiency is an inherited condition that causes neurological problems. Beginning in infancy to early childhood, children with this condition often have delayed development of mental and motor skills (psychomotor delay), speech delay, involuntary muscle cramping (dystonia), and spasms and weakness of the arms and legs (spastic quadriparesis). Affected individuals can also have optic atrophy, which is the degeneration (atrophy) of nerve cells that carry visual information from the eyes to the brain. In some cases, signs and symptoms of 3-methylglutaconyl-CoA hydratase deficiency begin in adulthood, often in a person's twenties or thirties. These individuals have damage to a type of brain tissue called white matter (leukoencephalopathy), which likely contributes to progressive problems with speech (dysarthria), difficulty coordinating movements (ataxia), stiffness (spasticity), optic atrophy, and a decline in intellectual function (dementia). Affected individuals who show symptoms of 3-methylglutaconyl-CoA hydratase deficiency in childhood often go on to develop leukoencephalopathy and other neurological problems in adulthood. All people with 3-methylglutaconyl-CoA hydratase deficiency accumulate large amounts of a substance called 3-methylglutaconic acid in their body fluids. As a result, they have elevated levels of acid in their blood (metabolic acidosis) and excrete large amounts of acid in their urine (aciduria). 3-methylglutaconyl-CoA hydratase deficiency is one of a group of metabolic disorders that can be diagnosed by the presence of increased levels 3-methylglutaconic acid in urine (3-methylglutaconic aciduria). People with 3-methylglutaconyl-CoA hydratase deficiency also have high urine levels of another acid called 3-methylglutaric acid.
3-Hydroxyisobutyric aciduria
MedGen UID:
90996
Concept ID:
C0342737
Disease or Syndrome
Beta-hydroxyisobutyryl-CoA deacylase deficiency
MedGen UID:
83349
Concept ID:
C0342738
Disease or Syndrome
3-Hydroxyisobutyrl-CoA hydrolase deficiency is an autosomal recessive inborn error of metabolism characterized by severely delayed psychomotor development, neurodegeneration, increased lactic acid, and brain lesions in the basal ganglia (summary by Ferdinandusse et al., 2013).
Deficiency of butyryl-CoA dehydrogenase
MedGen UID:
90998
Concept ID:
C0342783
Disease or Syndrome
The clinical findings in those with confirmed short-chain acyl-coA dehydrogenase (SCAD) deficiency range from severe (dysmorphic facial features, feeding difficulties/failure to thrive, metabolic acidosis, ketotic hypoglycemia, lethargy, developmental delay, seizures, hypotonia, dystonia, and myopathy) to normal. As in other fatty acid oxidation disorders, characteristic biochemical findings of SCAD deficiency may be absent except during times of physiologic stress such as fasting and illness. In the largest series of affected individuals published to date, 20% had failure to thrive, feeding difficulties, and hypotonia; 22% had seizures, and 30% had hypotonia without seizures. In contrast, the majority of infants with SCAD deficiency have been detected by expanded newborn screening, and the great majority of these infants remain asymptomatic. Because most infants with SCAD deficiency identified through newborn screening programs have been well at the time of diagnosis and asymptomatic relatives who meet diagnostic criteria are reported, the relationship of clinical manifestations to SCAD deficiency has come into question.
Carnitine palmitoyltransferase I deficiency
MedGen UID:
87461
Concept ID:
C0342789
Disease or Syndrome
Carnitine palmitoyltransferase 1A (CPT1A) deficiency is a disorder of long-chain fatty acid oxidation. Clinical symptoms usually occur in an individual with a concurrent febrile or gastrointestinal illness when energy demands are increased; onset of symptoms is usually rapid. The three recognized phenotypes are hepatic encephalopathy, in which individuals (typically children) present with hypoketotic hypoglycemia and sudden onset of liver failure; adult-onset myopathy, seen in one individual of Inuit origin; and acute fatty liver of pregnancy, in which the fetus is homozygous for a mutation in CPT1A that causes CPT1A deficiency. Between episodes of hepatic encephalopathy, individuals appear developmentally and cognitively normal unless previous metabolic decompensation has resulted in neurologic damage.
Carnitine acylcarnitine translocase deficiency
MedGen UID:
91000
Concept ID:
C0342791
Disease or Syndrome
Carnitine-acylcarnitine translocase deficiency is a rare autosomal recessive metabolic disorder of long-chain fatty acid oxidation. Metabolic consequences include hypoketotic hypoglycemia under fasting conditions, hyperammonemia, elevated creatine kinase and transaminases, dicarboxylic aciduria, very low free carnitine and abnormal acylcarnitine profile with marked elevation of the long-chain acylcarnitines. Clinical features include neurologic abnormalities, cardiomyopathy and arrhythmias, skeletal muscle damage, and liver dysfunction. Most patients become symptomatic in the neonatal period with a rapidly progressive deterioration and a high mortality rate. However, presentations at a later age with a milder phenotype have been reported (summary by Rubio-Gozalbo et al., 2004).
Deficiency of malonyl-CoA decarboxylase
MedGen UID:
91001
Concept ID:
C0342793
Disease or Syndrome
Malonyl-CoA decarboxylase deficiency is an uncommon inherited metabolic disease. The characteristic phenotype is variable, but may include developmental delay in early childhood, seizures, hypotonia, diarrhea, vomiting, metabolic acidosis, hypoglycemia, ketosis, abnormal urinary compounds, lactic acidemia, and hypertrophic cardiomyopathy (Sweetman and Williams, 2001).
Dihydropyrimidinase deficiency
MedGen UID:
83353
Concept ID:
C0342803
Disease or Syndrome
DPYS deficiency is an autosomal recessive inborn error of pyrimidine metabolism. Less than a dozen affected individuals have been reported. About half are asymptomatic, but rare patients with neurologic abnormalities have been reported. It is unclear whether or not these abnormalities are related to the enzymatic defect. Affected individuals theoretically could have severe toxicity after the administration of the antineoplastic drug 5-fluorouracil (5FU), although no cases have been reported (Hamajima et al., 1998; van Kuilenburg et al., 2007). See also dihydropyrimidine dehydrogenase deficiency (274270), a similar disorder.
Beta-D-mannosidosis
MedGen UID:
87462
Concept ID:
C0342849
Disease or Syndrome
Beta-mannosidosis is an autosomal recessive lysosomal storage disease of glycoprotein catabolism caused by a deficiency of lysosomal beta-mannosidase activity. The most severely affected patients show developmental delay and mental retardation, but there are differing levels of severity and some patients may have comparatively mild disease (Bedilu et al., 2002) The disorder was first described in goats (Jones and Dawson, 1981), who have a more severe neurodegenerative disorder than that seen in humans.
Sialuria
MedGen UID:
137980
Concept ID:
C0342853
Disease or Syndrome
Sialuria is characterized by variable and transient signs and symptoms, especially in infancy. These include slightly flat and coarse facies, prolonged neonatal jaundice, equivocal or mild hepatomegaly, microcytic anemia, frequent upper respiratory infections, and episodes of gastroenteritis, dehydration, and transient failure to thrive. Mild developmental delay and hypotonia have been neither consistent nor permanent. Learning difficulty and seizures have been observed later in childhood. Sialuria has been detected retrospectively in an adult without subjective signs or complaints of disease. The long-term outcome of the disorder is unknown to date.
Bifunctional peroxisomal enzyme deficiency
MedGen UID:
137982
Concept ID:
C0342870
Pathologic Function
D-bifunctional protein deficiency is a disorder of peroxisomal fatty acid beta-oxidation. See also peroxisomal acyl-CoA oxidase deficiency (264470), caused by mutation in the ACOX1 gene (609751) on chromosome 17q25. The clinical manifestations of these 2 deficiencies are similar to those of disorders of peroxisomal assembly, including X-linked adrenoleukodystrophy (ALD; 300100), Zellweger cerebrohepatorenal syndrome (see 214100) and neonatal adrenoleukodystrophy (NALD; see 601539) (Watkins et al., 1995). DBP deficiency has been classified into 3 subtypes depending upon the deficient enzyme activity. Type I is a deficiency of both 2-enoyl-CoA hydratase and 3-hydroxyacyl-CoA dehydrogenase; type II is a deficiency of hydratase activity alone; and type III is a deficiency of dehydrogenase activity alone. Virtually all patients with types I, II, and III have a severe phenotype characterized by infantile-onset of hypotonia, seizures, and abnormal facial features, and most die before age 2 years. McMillan et al. (2012) proposed a type IV deficiency on the basis of less severe features; these patients have a phenotype reminiscent of Perrault syndrome (PRLTS1; 233400). Pierce et al. (2010) noted that Perrault syndrome and DBP deficiency overlap clinically and suggested that DBP deficiency may be underdiagnosed.
Flynn-Aird syndrome
MedGen UID:
91009
Concept ID:
C0343108
Congenital Abnormality
Congenital livedo reticularis
MedGen UID:
83381
Concept ID:
C0345419
Congenital Abnormality
Carbohydrate-deficient glycoprotein syndrome type I
MedGen UID:
138111
Concept ID:
C0349653
Disease or Syndrome
PMM2-CDG (CDG-Ia) (previously known as congenital disorder of glycosylation type 1a), the most common of a group of disorders of abnormal glycosylation of N-linked oligosaccharides, is divided into three stages: infantile multisystem, late-infantile and childhood ataxia-intellectual disability, and adult stable disability. The three stages notwithstanding, clinical presentation and course are highly variable, ranging from infants who die in the first year of life to mildly involved adults. Clinical presentations tend to be similar in siblings. In the infantile multisystem stage, infants show axial hypotonia, hyporeflexia, esotropia, and developmental delay; feeding problems, vomiting, and diarrhea with failure to thrive; and impaired growth. Subcutaneous fat may be excessive over the buttocks and suprapubic region. Two distinct clinical presentations are observed: (1) a non-fatal neurologic form with strabismus, psychomotor retardation, and cerebellar hypoplasia in infancy followed by neuropathy and retinitis pigmentosa in the first or second decade and (2) a neurologic-multivisceral form with approximately 20% mortality in the first year of life. The late-infantile and childhood ataxia-intellectual disability stage, with onset between age three and ten years, is characterized by hypotonia, ataxia, severely delayed language and motor development, inability to walk, and IQ of 40 to 70; other findings include stroke-like episodes or transient unilateral loss of function, retinitis pigmentosa, joint contractures, and skeletal deformities. In the adult stable disability stage, intellectual ability is stable; peripheral neuropathy is variable, thoracic and spinal deformities progress, and premature aging is observed; females lack secondary sexual development and males may exhibit decreased testicular volume. Hyperglycemia-induced growth hormone release, hyperprolactinemia, insulin resistance, and coagulopathy may occur. An increased risk of deep venous thrombosis is present.
Carbohydrate-deficient glycoprotein syndrome type II
MedGen UID:
87610
Concept ID:
C0349654
Disease or Syndrome
Congenital disorders of N-linked glycosylation (abbreviated here as CDG-N-linked), are a group of disorders of N-linked oligosaccharides caused by deficiency in 42 different enzymes in the N-linked synthetic pathway. Most commonly, the disorders begin in infancy; manifestations range from severe developmental delay and hypotonia with multiple organ system involvement to hypoglycemia and protein-losing enteropathy with normal development. However, most types have been described in only a few individuals, and thus understanding of the phenotypes is limited. In PMM2-CDG (CDG-Ia), the most common type reported, the clinical presentation and course are highly variable, ranging from death in infancy to mild involvement in adults.
Branchiooculofacial syndrome
MedGen UID:
91261
Concept ID:
C0376524
Congenital Abnormality
The branchiooculofacial syndrome (BOFS) is characterized by: branchial (cervical [90%] or infra- or supra-auricular [60%]) skin defects that range from barely perceptible thin skin or hair patch to erythematous “hemangiomatous” lesions to large weeping erosions; ocular anomalies that can include microphthalmia, anophthalmia, coloboma, and nasolacrimal duct stenosis/atresia; and facial anomalies that can include ocular hypertelorism or telecanthus, broad nasal tip, upslanted palpebral fissures, cleft lip or prominent philtral pillars that give the appearance of a repaired cleft lip (formerly called "pseudocleft lip") with or without cleft palate, upper lip pits and lower facial weakness (asymmetric crying face or partial 7(th) cranial nerve weakness). Malformed and prominent pinnae and hearing loss from inner ear and/or petrous bone anomalies are common. Intellect is usually normal.
Roberts-SC phocomelia syndrome
MedGen UID:
95931
Concept ID:
C0392475
Congenital Abnormality
Roberts syndrome (RBS) is characterized by prenatal growth retardation (ranging from mild to severe), craniofacial findings (including microcephaly and cleft lip and/or palate) and limb malformations (including bilateral symmetric tetraphocomelia or hypomelia caused by mesomelic shortening). Upper limbs are more severely affected than lower limbs. Other limb malformations include oligodactyly with thumb aplasia or hypoplasia, syndactyly, clinodactyly, and elbow and knee flexion contractures. Craniofacial abnormalities include cleft lip and/or cleft palate, premaxillary prominence, micrognathia, microbrachycephaly, malar flattening, downslanted palpebral fissures, widely spaced eyes, exophthalmos resulting from shallow orbits, corneal clouding, underdeveloped ala nasi, beaked nose, and ear malformations. Intellectual disability is reported in the majority of affected individuals. Mortality is high among severely affected pregnancies and newborns. Mildly affected individuals may survive to adulthood.
Choreoacanthocytosis
MedGen UID:
98277
Concept ID:
C0393576
Disease or Syndrome
Chorea-acanthocytosis (ChAc) is characterized by a progressive movement disorder, cognitive and behavior changes, a myopathy that can be subclinical, and chronic hyperCKemia in serum. Although the disorder is named for acanthocytosis of the red blood cells, this feature is variable. The movement disorder is mostly limb chorea, but some individuals present with parkinsonism. Dystonia is common and affects the oral region and especially the tongue, causing dysarthria and serious dysphagia with resultant weight loss. Habitual tongue and lip biting are characteristic, as well as tongue protrusion dystonia. Progressive cognitive and behavioral changes resemble those in a frontal lobe syndrome. Seizures are observed in almost half of affected individuals and can be the initial manifestation. Myopathy results in progressive distal muscle wasting and weakness. Mean age of onset in ChAc is about 30 years, although ChAc can develop as early as the first decade or as late as the seventh decade. It runs a chronic progressive course and may lead to major disability within a few years. Life expectancy is reduced, with age of death ranging from 28 to 61 years.
Dysequilibrium syndrome
MedGen UID:
98295
Concept ID:
C0394006
Disease or Syndrome
VLDLR-associated cerebellar hypoplasia (VLDLR-CH) is characterized by non-progressive congenital ataxia that is predominantly truncal and results in delayed ambulation, moderate-to-profound intellectual disability, dysarthria, strabismus, and seizures. Children either learn to walk very late (often after age 6 years) or never achieve independent ambulation.
Hyperimmunoglobulin D with periodic fever
MedGen UID:
140768
Concept ID:
C0398691
Disease or Syndrome
Mevalonate kinase deficiency is a condition characterized by recurrent episodes of fever, which typically begin during infancy. Each episode of fever lasts about 3 to 6 days, and the frequency of the episodes varies among affected individuals. In childhood the fevers seem to be more frequent, occurring as often as 25 times a year, but as the individual gets older the episodes occur less often. Mevalonate kinase deficiency has additional signs and symptoms, and the severity depends on the type of the condition. There are two types of mevalonate kinase deficiency: a less severe type called hyperimmunoglobulinemia D syndrome (HIDS) and a more severe type called mevalonic aciduria (MVA). During episodes of fever, people with HIDS typically have enlargement of the lymph nodes (lymphadenopathy), abdominal pain, joint pain, diarrhea, skin rashes, and headache. Occasionally they will have painful sores called aphthous ulcers around their mouth. In females, these may also occur around the vagina. A small number of people with HIDS have intellectual disability, problems with movement and balance (ataxia), eye problems, and recurrent seizures (epilepsy). Rarely, people with HIDS develop a buildup of protein deposits (amyloidosis) in the kidneys that can lead to kidney failure. Fever episodes in individuals with HIDS can be triggered by vaccinations, surgery, injury, or stress. Most people with HIDS have abnormally high levels of immune system proteins called immunoglobulin D (IgD) and immunoglobulin A (IgA) in the blood. It is unclear why people with HIDS have high levels of IgD and IgA. Elevated levels of these immunoglobulins do not appear to cause any signs or symptoms. Individuals with HIDS do not have any signs and symptoms of the condition between fever episodes and typically have a normal life expectancy. People with MVA have signs and symptoms of the condition at all times, not just during episodes of fever. Affected children have developmental delay, progressive ataxia, progressive problems with vision, and failure to gain weight and grow at the expected rate (failure to thrive). Individuals with MVA typically have an unusually small, elongated head. In childhood or adolescence, affected individuals may develop eye problems such as inflammation of the eye (uveitis), a blue tint in the white part of the eye (blue sclera), an eye disorder called retinitis pigmentosa that causes vision loss, or clouding of the lens of the eye (cataracts). Affected adults may have short stature and may develop muscle weakness (myopathy) later in life. During fever episodes, people with MVA may have an enlarged liver and spleen (hepatosplenomegaly), lymphadenopathy, abdominal pain, diarrhea, and skin rashes. Children with MVA who are severely affected with multiple problems may live only into early childhood; mildly affected individuals may have a normal life expectancy.
Gluthathione synthetase deficiency
MedGen UID:
97988
Concept ID:
C0398746
Disease or Syndrome
Glutathione synthetase deficiency, or 5-oxoprolinuria, is an autosomal recessive disorder characterized, in its severe form, by massive urinary excretion of 5-oxoproline, metabolic acidosis, hemolytic anemia, and central nervous system damage. The metabolic defect results in decreased levels of cellular glutathione, which overstimulates the synthesis of gamma-glutamylcysteine and its subsequent conversion to 5-oxoproline (Larsson and Anderson, 2001).
Wrinkly skin syndrome
MedGen UID:
98030
Concept ID:
C0406587
Disease or Syndrome
ATP6V0A2-related cutis laxa, also known as autosomal recessive cutis laxa type 2A (ARCL2A), spans a phenotypic spectrum that includes Debré-type cutis laxa at the severe end and wrinkly skin syndrome at the mild end. Affected individuals have furrowing of the skin of the whole body that improves with time. They may have other evidence of a generalized connective disorder, including enlarged anterior fontanelle in infancy, congenital dislocation of the hips, inguinal hernias, and high myopia. In most (not all) affected individuals, cortical and cerebellar malformations are present and are associated with severe developmental delays, seizures, and neurologic regression.
Encephalocraniocutaneous lipomatosis
MedGen UID:
140807
Concept ID:
C0406612
Congenital Abnormality
Encephalocraniocutaneous lipomatosis (ECCL) is a neurocutaneous disorder characterized by ocular anomalies, skin lesions, and central nervous system anomalies (Moog et al., 2007).
Kohlschutter's syndrome
MedGen UID:
98036
Concept ID:
C0406740
Congenital Abnormality
Kohlschutter-Tonz syndrome is an autosomal recessive disorder characterized by severe global developmental delay, early-onset intractable seizures, spasticity, and amelogenesis imperfecta affecting both primary and secondary teeth and causing yellow or brown discoloration of the teeth. Although the phenotype is consistent, there is variability. Intellectual disability is related to the severity of seizures, and the disorder can thus be considered an epileptic encephalopathy. Some infants show normal development until seizure onset, whereas others are delayed from birth. The most severely affected individuals have profound mental retardation, never acquire speech, and become bedridden early in life (summary by Schossig et al., 2012 and Mory et al., 2012).
Fukuyama congenital muscular dystrophy
MedGen UID:
140820
Concept ID:
C0410174
Disease or Syndrome
Fukuyama congenital muscular dystrophy (FCMD) is characterized by hypotonia, symmetric generalized muscle weakness, and CNS migration disturbances that result in changes consistent with cobblestone (previously type II) lissencephaly with cerebral and cerebellar cortical dysplasia. Mild, typical, and severe phenotypes are recognized. Onset typically occurs in early infancy, with a poor suck, weak cry, and floppiness. Affected individuals have contractures of the hips, knees, and interphalangeal joints. Later features include myopathic facial appearance, pseudohypertrophy of the calves and forearms, motor and speech retardation, intellectual disability, seizures, ophthalmologic abnormalities including visual impairment and retinal dysplasia, and progressive cardiac involvement in individuals older than age ten years. Swallowing disturbance occurs in individuals with severe FCMD and in individuals older than age ten years, leading to recurrent aspiration pneumonia and death.
Severe X-linked myotubular myopathy
MedGen UID:
98374
Concept ID:
C0410203
Congenital Abnormality
X-linked centronuclear myopathy (XLCNM) (also known as myotubular myopathy [MTM]) is characterized by muscle weakness that ranges from severe to mild. Severe (classic) XLCNM presents prenatally with polyhydramnios and decreased fetal movement and in newborns with weakness, hypotonia and respiratory distress. Affected males have significantly delayed motor milestones and most fail to achieve independent ambulation. Weakness is profound and often involves facial and extraocular muscles. Respiratory failure is nearly uniform, with most affected individuals requiring 24-hour ventilatory assistance. A minority of males with severe XLCNM die in infancy. Males with moderate XLCNM achieve motor milestones more quickly than males with the severe form; about 40% require no ventilator support or intermittent support. Males with mild XLCNM may require ventilatory support only in the newborn period; they have minimally delayed motor milestones, are able to walk, and may lack myopathic facies. The muscle disease of XLCNM is not obviously progressive. Female carriers of XLCNM are generally asymptomatic, although rare manifesting heterozygotes have been described.
Wolcott-Rallison dysplasia
MedGen UID:
140926
Concept ID:
C0432217
Congenital Abnormality
Wolcott-Rallison syndrome is a rare autosomal recessive disorder characterized by permanent neonatal or early infancy insulin-dependent diabetes. Epiphyseal dysplasia, osteoporosis, and growth retardation develop at a later age. Other frequent multisystem manifestations include hepatic and renal dysfunction, mental retardation, and cardiovascular abnormalities (summary by Delepine et al., 2000).
Dysosteosclerosis
MedGen UID:
98150
Concept ID:
C0432262
Disease or Syndrome
Dysosteosclerosis is a rare bone dysplasia associated with neurodevelopmental deterioration. There is sclerosis and platyspondyly with progressive metaphyseal expansion and alteration of bone density. The early craniotubular bone modeling and clinical presentation resemble osteopetrosis (summary by Elcioglu et al., 2002).
Osteopathia striata with cranial sclerosis
MedGen UID:
96590
Concept ID:
C0432268
Disease or Syndrome
Osteopathia striata with cranial sclerosis is an X-linked dominant sclerosing bone dysplasia that presents in females with macrocephaly, cleft palate, mild learning disabilities, sclerosis of the long bones and skull, and longitudinal striations visible on radiographs of the long bones, pelvis, and scapulae (Jenkins et al., 2009). In males, the disorder is usually associated with fetal or neonatal lethality. Occasional surviving males have, in addition to hyperostosis, cardiac, intestinal, and genitourinary malformations. Osteosclerosis in the cranial and facial bones leads to disfigurement and to disability due to pressure on cranial nerves, e.g., deafness. Osteopathia striata is a frequent feature of focal dermal hypoplasia (FDH; 305600). Although early reports of familial cases of this disorder appeared to suggest autosomal dominant inheritance (see, e.g., Horan and Beighton, 1978 and Konig et al., 1996), reappraisal of the literature (Behninger and Rott, 2000; Rott et al., 2003) and the finding of a molecular basis for the disorder by Jenkins et al. (2009) confirms that the inheritance pattern is X-linked dominant. Affected males who survive have a more severe phenotype than affected females, and sporadic male cases may result from somatic mosaicism (Behninger and Rott, 2000).
Deletion of long arm of chromosome 18
MedGen UID:
96605
Concept ID:
C0432443
Disease or Syndrome
A rare genetic syndrome characterized by the deletion of the long arm of chromosome 18. It is associated with short stature, hypotonia, mental retardation, and hand, foot, skull and facial abnormalities.
Muscle eye brain disease
MedGen UID:
105341
Concept ID:
C0457133
Congenital Abnormality
Congenital muscular dystrophy (CMD) is a clinically and genetically heterogeneous group of inherited muscle disorders. Muscle weakness typically presents from birth to early infancy. Affected infants typically appear "floppy" with low muscle tone and poor spontaneous movements. Affected children may present with delay or arrest of gross motor development together with joint and/or spinal rigidity. Muscle weakness may improve, worsen, or stabilize in the short term; however, with time progressive weakness and joint contractures, spinal deformities, and respiratory compromise may affect quality of life and life span. The main CMD subtypes, grouped by involved protein function and gene in which causative mutations occur, are laminin alpha-2 (merosin) deficiency (MDC1A), collagen VI-deficient CMD, the dystroglycanopathies (caused by mutations in POMT1, POMT2, FKTN, FKRP, LARGE, POMGNT1, and ISPD), SEPN1-related CMD (previously known as rigid spine syndrome, RSMD1) and LMNA-related CMD (L-CMD). Several less known CMD subtypes have been reported in a limited number of individuals. Cognitive impairment ranging from intellectual disability to mild cognitive delay, structural brain and/or eye abnormalities, and seizures are found almost exclusively in the dystroglycanopathies while white matter abnormalities without major cognitive involvement tend to be seen in the laminin alpha-2-deficient subtype.
Neurocutaneous melanosis
MedGen UID:
154259
Concept ID:
C0544862
Pathologic Function
Neurocutaneous melanosis, or neuromelanosis, is characterized by the presence of melanin-producing cells within the brain parenchyma or leptomeninges, which may lead to clinically apparent neurologic signs and symptoms, such as seizures. Other neurologic abnormalities, including hydrocephalus, arachnoid cysts, tumors, and syringomyelia, may also occur. The disorder is a rare but severe manifestation of congenital melanocytic nevus syndrome (CMNS; 137550). Some patients with neurocutaneous melanosis or CMNS may develop malignant melanoma. The incidence of neurologic involvement, development of malignant melanoma, and death is significantly associated with the projected adult size of the largest congenital melanocytic nevus, particularly those greater than 40 cm (summary by Kinsler et al., 2008; Kinsler et al., 2013).
Beaded hair
MedGen UID:
108185
Concept ID:
C0546966
Congenital Abnormality
Individuals with monilethrix have normal hair at birth, but within the first few months of life develop fragile, brittle hair that tends to fracture and produce varying degrees of dystrophic alopecia. In the mildest forms, only the occipital regions of the scalp are involved; however, in severe forms the eyebrows, eyelashes, and secondary sexual hair may also be involved. Follicular hyperkeratosis with predilection for the scalp, nape of neck, and extensor surfaces of the upper arm and thighs is also a characteristic finding in these patients. Light microscopic examination is diagnostic and reveals elliptical nodes of normal thickness and intermittent constrictions (internodes) at which the hair easily breaks. There may be spontaneous improvement with time, especially during puberty and pregnancy, but the condition never resolves completely (summary by Zlotogorski et al., 2006). An autosomal recessive form of monilethrix-like congenital hypotrichosis (see 607903) is caused by mutation in the DSG4 gene (607892). The clinical picture of autosomal recessive monilethrix is more severe than the dominant form, with more extensive alopecia of the scalp, body, and limbs, and a papular rash involving the extremities and periumbilical region (Zlotogorski et al., 2006). The term monilethrix derives from the Latin word for necklace and the Greek for hair (Schweizer, 2006).
Deficiency of guanidinoacetate methyltransferase
MedGen UID:
154356
Concept ID:
C0574080
Disease or Syndrome
The cerebral creatine deficiency syndromes (CCDS), inborn errors of creatine metabolism, include the two creatine biosynthesis disorders, guanidinoacetate methyltransferase (GAMT) deficiency and L-arginine:glycine amidinotransferase (AGAT or GATM) deficiency, and the creatine transporter (SLC6A8) deficiency. Intellectual disability and seizures are common to all three CCDS. The majority of individuals with GAMT deficiency have a behavior disorder that can include autistic behaviors and self-mutilation; a significant proportion have pyramidal/extrapyramidal findings. Onset is between ages three months and three years. Only seven individuals with AGAT deficiency have been reported. The phenotype of SLC6A8 deficiency in affected males ranges from mild intellectual disability and speech delay to severe intellectual disability, seizures, and behavior disorder; age at diagnosis ranges from two to 66 years. Females heterozygous for SLC6A8 deficiency may have learning and behavior problems.
Cockayne syndrome, type B
MedGen UID:
155487
Concept ID:
C0751038
Disease or Syndrome
Cockayne syndrome (referred to as CS in this GeneReview) spans a phenotypic spectrum that includes: CS type I, the "classic" or “moderate” form; CS type II, a more severe form with symptoms present at birth; this form overlaps with cerebrooculofacioskeletal syndrome (COFS) or Pena-Shokeir syndrome type II; CS type III, a milder form; Xeroderma pigmentosum-Cockayne syndrome (XP-CS). CS type I (moderate CS) is characterized by normal prenatal growth with the onset of growth and developmental abnormalities in the first two years. By the time the disease has become fully manifest, height, weight, and head circumference are far below the fifth percentile. Progressive impairment of vision, hearing, and central and peripheral nervous system function leads to severe disability; death typically occurs in the first or second decade. CS type II (severe CS or early-onset CS) is characterized by growth failure at birth, with little or no postnatal neurologic development. Congenital cataracts or other structural anomalies of the eye may be present. Affected children have early postnatal contractures of the spine (kyphosis, scoliosis) and joints. Death usually occurs by age seven years. CS type III (mild CS or late-onset CS) is characterized by essentially normal growth and cognitive development or by late onset. Xeroderma pigmentosum-Cockayne syndrome (XP-CS) includes facial freckling and early skin cancers typical of XP and some features typical of CS, including intellectual disability, spasticity, short stature, and hypogonadism. XP-CS does not include skeletal involvement, the facial phenotype of CS, or CNS dysmyelination and calcifications.
Cockayne syndrome type A
MedGen UID:
155488
Concept ID:
C0751039
Disease or Syndrome
Cockayne syndrome (referred to as CS in this GeneReview) spans a phenotypic spectrum that includes: CS type I, the "classic" or “moderate” form; CS type II, a more severe form with symptoms present at birth; this form overlaps with cerebrooculofacioskeletal syndrome (COFS) or Pena-Shokeir syndrome type II; CS type III, a milder form; Xeroderma pigmentosum-Cockayne syndrome (XP-CS). CS type I (moderate CS) is characterized by normal prenatal growth with the onset of growth and developmental abnormalities in the first two years. By the time the disease has become fully manifest, height, weight, and head circumference are far below the fifth percentile. Progressive impairment of vision, hearing, and central and peripheral nervous system function leads to severe disability; death typically occurs in the first or second decade. CS type II (severe CS or early-onset CS) is characterized by growth failure at birth, with little or no postnatal neurologic development. Congenital cataracts or other structural anomalies of the eye may be present. Affected children have early postnatal contractures of the spine (kyphosis, scoliosis) and joints. Death usually occurs by age seven years. CS type III (mild CS or late-onset CS) is characterized by essentially normal growth and cognitive development or by late onset. Xeroderma pigmentosum-Cockayne syndrome (XP-CS) includes facial freckling and early skin cancers typical of XP and some features typical of CS, including intellectual disability, spasticity, short stature, and hypogonadism. XP-CS does not include skeletal involvement, the facial phenotype of CS, or CNS dysmyelination and calcifications.
Juvenile neuronal ceroid lipofuscinosis
MedGen UID:
155549
Concept ID:
C0751383
Disease or Syndrome
The neuronal ceroid-lipofuscinoses (NCLs) are a group of inherited, neurodegenerative, lysosomal storage disorders characterized by progressive intellectual and motor deterioration, seizures, and early death. Visual gvhmloss is a feature of most forms. Clinical phenotypes have been characterized traditionally according to the age of onset and order of appearance of clinical features into infantile, late-infantile, juvenile, adult, and Northern epilepsy (also known as progressive epilepsy with mental retardation [EPMR]). There is however genetic and allelic heterogeneity; a proposed new nomenclature and classification system has been developed to take into account both the responsible gene and the age at disease onset; for example, CLN1 disease, infantile onset and CLN1 disease, juvenile onset are both caused by mutations in PPT1 but with differing age of onset. The most prevalent NCLs are CLN3 disease, classic juvenile and CLN2 disease, classic late infantile (although prevalence varies by ethnicity and country of family origin): CLN2 disease, classic late infantile. The first symptoms typically appear between age two and four years, usually starting with epilepsy, followed by regression of developmental milestones, myoclonic ataxia, and pyramidal signs. Visual impairment typically appears at age four to six years and rapidly progresses to light /dark awareness only. Life expectancy ranges from age six years to early teenage. CLN3 disease, classic juvenile. Onset is usually between ages four and ten years. Rapidly progressing visual loss resulting in severe visual impairment within one to two years is often the first clinical sign. Epilepsy with generalized tonic-clonic seizures and/or complex-partial seizures typically appears around age ten years. Life expectancy ranges from the late teens to the 30s. Other forms of NCL may present with behavior changes, epilepsy, visual impairment, or slowing of developmental progress and then loss of skills. The course may be extremely variable. Some genotype-phenotype information is available.
Lymphangiomyomatosis
MedGen UID:
148366
Concept ID:
C0751674
Neoplastic Process
Lymphangioleiomyomatosis (LAM) is a condition that affects the lungs, the kidneys, and the lymphatic system. The lymphatic system consists of a network of vessels that transport lymph fluid and immune cells throughout the body. LAM is found almost exclusively in women. It usually occurs as a feature of an inherited syndrome called tuberous sclerosis complex. When LAM occurs alone it is called isolated or sporadic LAM. Signs and symptoms of LAM most often appear during a woman's thirties. Affected women have an overgrowth of abnormal smooth muscle-like cells (LAM cells) in the lungs, resulting in the formation of lung cysts and the destruction of normal lung tissue. They may also have an accumulation of fluid in the cavity around the lungs (chylothorax). The lung abnormalities resulting from LAM may cause difficulty breathing (dyspnea), chest pain, and coughing, which may bring up blood (hemoptysis). Many women with this disorder have recurrent episodes of collapsed lung (spontaneous pneumothorax). The lung problems may be progressive and, without lung transplantation, may eventually lead to limitations in activities of daily living, the need for oxygen therapy, and respiratory failure. Although LAM cells are not considered cancerous, they may spread between tissues (metastasize). As a result, the condition may recur even after lung transplantation. Women with LAM may develop cysts in the lymphatic vessels of the chest and abdomen. These cysts are called lymphangioleiomyomas. Affected women may also develop tumors called angiomyolipomas made up of LAM cells, fat cells, and blood vessels. Angiomyolipomas usually develop in the kidneys. Internal bleeding is a common complication of angiomyolipomas.
Non-ketotic hyperglycinemia
MedGen UID:
155625
Concept ID:
C0751748
Disease or Syndrome
Glycine encephalopathy, also known as nonketotic hyperglycinemia (NKH), is an inborn error of glycine metabolism defined by deficient activity of the glycine cleavage enzyme and, as a consequence, accumulation of large quantities of glycine in all body tissues including the brain. The majority of glycine encephalopathy presents in the neonatal period (85% as the neonatal severe form and 15% as the neonatal attenuated form). Of those presenting in infancy, 50% have the infantile attenuated form and 50% have the infantile severe form. Overall, 20% of all children presenting as either neonates or infants have a less severe outcome, defined as developmental quotient greater than 20. A minority of patients have mild or atypical forms of glycine encephalopathy. The neonatal form manifests in the first hours to days of life with progressive lethargy, hypotonia, and myoclonic jerks leading to apnea and often death. Surviving infants have profound intellectual disability and intractable seizures. The infantile form is characterized by hypotonia, developmental delay, and seizures. The atypical forms range from milder disease, with onset from late infancy to adulthood, to rapidly progressing and severe disease with late onset.
Congenital hyperammonemia, type I
MedGen UID:
199727
Concept ID:
C0751753
Disease or Syndrome
Carbamoyl phosphate synthetase I deficiency is an autosomal recessive inborn error of metabolism of the urea cycle which causes hyperammonemia. There are 2 main forms: a lethal neonatal type and a less severe, delayed-onset type (summary by Klaus et al., 2009). Urea cycle disorders are characterized by the triad of hyperammonemia, encephalopathy, and respiratory alkalosis. Five disorders involving different defects in the biosynthesis of the enzymes of the urea cycle have been described: ornithine transcarbamylase deficiency (311250), carbamyl phosphate synthetase deficiency, argininosuccinate synthetase deficiency, or citrullinemia (215700), argininosuccinate lyase deficiency (207900), and arginase deficiency (207800).
Dentatorubral pallidoluysian atrophy
MedGen UID:
155630
Concept ID:
C0751781
Disease or Syndrome
Dentatorubral-pallidoluysian atrophy (DRPLA) is a progressive disorder of ataxia, choreoathetosis, and dementia or character changes in adults and ataxia, myoclonus, epilepsy, and progressive intellectual deterioration in children. The age of onset is from one to 62 years with a mean age of onset of 30 years. The clinical presentation varies depending on the age of onset. The cardinal features in adults are ataxia, choreoathetosis, and dementia. Cardinal features in children are progressive intellectual deterioration, behavioral changes, myoclonus, and epilepsy.
Recombinant chromosome 8 syndrome
MedGen UID:
167070
Concept ID:
C0795822
Disease or Syndrome
Recombinant 8 syndrome is a condition that involves heart and urinary tract abnormalities, moderate to severe intellectual disability, and a distinctive facial appearance. The characteristic facial features include a wide, square face; a thin upper lip; a downturned mouth; a small chin (micrognathia); wide-set eyes (hypertelorism); and low-set or unusually shaped ears. People with recombinant 8 syndrome may have overgrowth of the gums (gingival hyperplasia) and abnormal tooth development. Males with this condition frequently have undescended testes (cryptorchidism). Some affected individuals have recurrent ear infections (otitis media) or hearing loss. Many children with recombinant 8 syndrome do not survive past early childhood, usually due to complications related to their heart abnormalities.
Chromosome 9, monosomy 9p
MedGen UID:
167073
Concept ID:
C0795830
Disease or Syndrome
Partial deletion of the short arm of chromosome 9 with mental retardation, craniofacial anomalies, abnormal dermatoglyphics, short and webbed neck, heart murmurs, square nails, and other defects.
Chromosome 9q deletion syndrome
MedGen UID:
208639
Concept ID:
C0795833
Disease or Syndrome
Kleefstra syndrome is characterized by intellectual disability, childhood hypotonia, and distinctive facial features. The majority of individuals function in the moderate to severe spectrum of intellectual disability although a few individuals have mild delay and total IQ around 70. Although most have severe expressive speech delay with little speech development, general language development is usually at a higher level, making nonverbal communication possible. A complex pattern of other findings can also be observed including heart defects, renal/urologic defects, genital defects in males, severe respiratory infections, epilepsy/febrile seizures, autistic-like features in childhood, and extreme apathy or catatonic-like features after puberty.
11q partial monosomy syndrome
MedGen UID:
162878
Concept ID:
C0795841
Disease or Syndrome
Jacobsen syndrome is a condition caused by a loss of genetic material from chromosome 11. Because this deletion occurs at the end (terminus) of the long (q) arm of chromosome 11, Jacobsen syndrome is also known as 11q terminal deletion disorder. The signs and symptoms of Jacobsen syndrome vary considerably. Most affected individuals have delayed development, including the development of motor skills (such as sitting, standing, and walking) and speech. Most also have cognitive impairment and learning difficulties. Behavioral problems have been reported, including compulsive behavior (such as shredding paper), a short attention span, and easy distractibility. Many people with Jacobsen syndrome have been diagnosed with attention deficit-hyperactivity disorder (ADHD). Jacobsen syndrome is also characterized by distinctive facial features. These include small and low-set ears, widely set eyes (hypertelorism) with droopy eyelids (ptosis), skin folds covering the inner corner of the eyes (epicanthal folds), a broad nasal bridge, downturned corners of the mouth, a thin upper lip, and a small lower jaw. Affected individuals often have a large head size (macrocephaly) and a skull abnormality called trigonocephaly, which gives the forehead a pointed appearance. More than 90 percent of people with Jacobsen syndrome have a bleeding disorder called Paris-Trousseau syndrome. This condition causes a lifelong risk of abnormal bleeding and easy bruising. Paris-Trousseau syndrome is a disorder of platelets, which are blood cell fragments that are necessary for blood clotting. Other features of Jacobsen syndrome can include heart defects, feeding difficulties in infancy, short stature, frequent ear and sinus infections, and skeletal abnormalities. The disorder can also affect the digestive system, kidneys, and genitalia. The life expectancy of people with Jacobsen syndrome is unknown, although affected individuals have lived into adulthood.
Smith-Magenis syndrome
MedGen UID:
162881
Concept ID:
C0795864
Disease or Syndrome
Smith-Magenis syndrome (SMS) is characterized by distinctive physical features (particularly facial features that progress with age), developmental delay, cognitive impairment, and behavioral abnormalities. Infants have feeding difficulties, failure to thrive, hypotonia, hyporeflexia, prolonged napping or need to be awakened for feeds, and generalized lethargy. The majority of individuals function in the mild-to-moderate range of intellectual disability. The behavioral phenotype, including significant sleep disturbance, stereotypies, and maladaptive and self-injurious behaviors, is generally not recognized until age 18 months or older and continues to change until adulthood. Sensory integration issues are frequently noted. Children and adults typically have inattention, distractibility, hyperactivity, impulsivity, maladaptive behaviors including frequent outbursts/temper tantrums, attention seeking, disobedience, aggression, toileting difficulties, and self-injurious behaviors (SIB) including self-hitting, self-biting, and/or skin picking, inserting foreign objects into body orifices (polyembolokoilamania), and yanking fingernails and/or toenails (onychotillomania). Among the stereotypic behaviors described, the spasmodic upper-body squeeze or "self-hug" seems to be highly associated with SMS. The finger lick and page flipping ("lick and flip") behavior may be less prevalent than initially reported. An underlying developmental asynchrony, specifically between intellectual functioning and emotional maturity, may also contribute to maladaptive behaviors in people with SMS.
Chromosome 18, tetrasomy 18p
MedGen UID:
167079
Concept ID:
C0795868
Disease or Syndrome
Tetrasomy 18p is a developmental disorder that affects many parts of the body. This condition usually causes feeding difficulties in infancy, delayed development, intellectual disability, changes in muscle tone, distinctive facial features, and other birth defects. However, the signs and symptoms vary among affected individuals. Babies with tetrasomy 18p often have trouble feeding and may vomit frequently, which makes it difficult for them to gain weight. Some affected infants also have breathing problems and jaundice, which is a yellowing of the skin and the whites of the eyes. Changes in muscle tone are commonly seen with tetrasomy 18p. Some affected children have weak muscle tone (hypotonia), while others have increased muscle tone (hypertonia) and stiffness (spasticity). These changes contribute to delayed development of motor skills, including sitting, crawling, and walking. Tetrasomy 18p is associated with a distinctive facial appearance that can include unusually shaped and low-set ears, a small mouth, a flat area between the upper lip and the nose (philtrum), and a thin upper lip. Many affected individuals also have a high, arched roof of the mouth (palate). Additional features of tetrasomy 18p can include seizures, vision problems, recurrent ear infections, mild to moderate hearing loss, constipation and other gastrointestinal problems, abnormal curvature of the spine (scoliosis or kyphosis), and heart defects. Males with tetrasomy 18p may be born with undescended testes (cryptorchidism) or the opening of the urethra on the underside of the penis (hypospadias). Psychiatric conditions, such as attention deficit hyperactivity disorder (ADHD) and anxiety, have also been reported in some people with tetrasomy 18p.
Crome syndrome
MedGen UID:
167082
Concept ID:
C0795914
Disease or Syndrome
Cataracts, retarded growth and mental development, epilepsy, and variable neurological and other defects.
Chromosome 16-related alpha-thalassemia/mental retardation syndrome
MedGen UID:
162892
Concept ID:
C0795917
Disease or Syndrome
Alpha-thalassemia X-linked intellectual disability (ATRX) syndrome is characterized by distinctive craniofacial features, genital anomalies, severe developmental delays, hypotonia, intellectual disability, and mild-to-moderate anemia secondary to alpha-thalassemia. Craniofacial abnormalities include small head circumference, telecanthus or widely spaced eyes, short nose, tented vermilion of the upper lip, and thick or everted vermilion of the lower lip with coarsening of the facial features over time. Although all affected individuals have a normal 46,XY karyotype, genital anomalies range from hypospadias and undescended testicles to severe hypospadias and ambiguous genitalia, to normal-appearing female external genitalia. Global developmental delays are evident in infancy and some affected individuals never walk independently or develop significant speech.
Edinburgh malformation syndrome
MedGen UID:
167084
Concept ID:
C0795933
Disease or Syndrome
A syndrome reported in an Edinburgh family in which five infants (four female and one male) were found to have a characteristic facial appearance, hydrocephalus, and psychomotor retardation. Some characteristics of this syndrome are similar to those of the de Lange syndrome 1.
Filippi syndrome
MedGen UID:
163197
Concept ID:
C0795940
Disease or Syndrome
Filippi syndrome is characterized by short stature, microcephaly, syndactyly, intellectual disability, and facial dysmorphism consisting of bulging forehead, broad and prominent nasal bridge, and diminished alar flare. Common features include cryptorchidism, speech impairment, and clinodactyly of the fifth finger, Some patients exhibit visual disturbances, polydactyly, seizures, and/or ectodermal abnormalities, such as nail hypoplasia, long eyelashes, hirsutism, and microdontia (summary by Hussain et al., 2014).
Fine-Lubinsky syndrome
MedGen UID:
163198
Concept ID:
C0795941
Disease or Syndrome
A dysmorphic syndrome with variable expression characterized mainly by body asymmetry, developmental delay, brachycephaly, cataracts, and deafness.
Fountain syndrome
MedGen UID:
208650
Concept ID:
C0795944
Disease or Syndrome
Coarse facies, mental retardation, hearing loss, and skeletal abnormalities are the major symptoms.
Microcephaly, hiatal hernia and nephrotic syndrome
MedGen UID:
167086
Concept ID:
C0795949
Disease or Syndrome
Galloway-Mowat syndrome is a rare autosomal recessive disorder characterized by microcephaly and central nervous system abnormalities resulting in severe intellectual disability. Most patients also develop seizures and nephrotic syndrome later in childhood. Many affected children die in the first decade of life (summary by Colin et al., 2014).
Andermann syndrome
MedGen UID:
162893
Concept ID:
C0795950
Disease or Syndrome
Hereditary motor and sensory neuropathy with agenesis of the corpus callosum (HMSN/ACC), a neurodevelopmental and neurodegenerative disorder, is characterized by severe progressive sensorimotor neuropathy with resulting hypotonia, areflexia, and amyotrophy and variable degrees of dysgenesis of the corpus callosum. Mild-to-severe intellectual disability and "psychotic episodes" during adolescence are observed. Sensory modalities are moderately to severely affected beginning in infancy. The average age of onset of walking is 3.8 years; the average age of loss of walking is 13.8 years; the average age of death is 33 years.
Gomez Lopez Hernandez syndrome
MedGen UID:
163201
Concept ID:
C0795959
Disease or Syndrome
Cerebellotrigeminal dermal dysplasia, also known as Gomez-Lopez-Hernandez (GLH) syndrome, is a rare neurocutaneous syndrome classically characterized by the triad of rhombencephalosynapsis, trigeminal anesthesia, often giving rise to corneal opacities, and bilateral parietal or parietooccipital alopecia, However, trigeminal anesthesia is an inconsistent finding (summary by Sukhudyan et al., 2010).
Mental retardation Gustavson type, X-linked
MedGen UID:
167088
Concept ID:
C0795965
Disease or Syndrome
Mental retardation syndrome with microcephaly, severely impaired vision, hearing defect, epileptic seizures, restricted movement, and early death.
Harrod Doman Keele syndrome
MedGen UID:
162895
Concept ID:
C0795970
Disease or Syndrome
A rare syndrome of microcephaly with a long thin face and pointed chin, small mouth, malformed ears, hypotelorism, arachnodactyly, hypogenitalism and mental retardation.
Mental retardation-hypotonic facies syndrome X-linked, 1
MedGen UID:
167093
Concept ID:
C0796003
Disease or Syndrome
The term 'X-linked mental retardation-hypotonic facies syndrome' comprises several syndromes previously reported separately. These include Juberg-Marsidi, Carpenter-Waziri, Holmes-Gang, and Smith-Fineman-Myers syndromes as well as 1 family with X-linked mental retardation with spastic paraplegia. All these syndromes were found to be caused by mutation in the XH2 gene and are characterized primarily by severe mental retardation, dysmorphic facies, and a highly skewed X-inactivation pattern in carrier women (Abidi et al., 2005). Other more variable features include hypogonadism, deafness, renal anomalies, and mild skeletal defects. X-linked alpha-thalassemia/mental retardation syndrome (ATR-X; 301040) is an allelic disorder with a similar phenotype with the addition of alpha-thalassemia and Hb H inclusion bodies in erythrocytes.
Kabuki make-up syndrome
MedGen UID:
162897
Concept ID:
C0796004
Disease or Syndrome
Kabuki syndrome (KS) is characterized by typical facial features (elongated palpebral fissures with eversion of the lateral third of the lower eyelid; arched and broad eyebrows; short columella with depressed nasal tip; large, prominent, or cupped ears), minor skeletal anomalies, persistence of fetal fingertip pads, mild to moderate intellectual disability, and postnatal growth deficiency. Other findings may include: congenital heart defects, genitourinary anomalies, cleft lip and/or palate, gastrointestinal anomalies including anal atresia, ptosis and strabismus, and widely spaced teeth and hypodontia. Functional differences can include: increased susceptibility to infections and autoimmune disorders, seizures, endocrinologic abnormalities including isolated premature thelarche in females, feeding problems, and hearing loss.
Kapur Toriello syndrome
MedGen UID:
208654
Concept ID:
C0796005
Disease or Syndrome
Retarded mental and growth development with variable congenial defects, including heart abnormalities, intestinal malrotation, characteristic facies, and other anomalies.
Kifafa seizure disorder
MedGen UID:
208655
Concept ID:
C0796010
Disease or Syndrome
A convulsive seizure disorder observed in an isolated tribe in the interior of Tanzania. It is a chronic degenerative disorder of the central nervous system associated with seizures and other neurological complications, characteristic facies, psychomotor retardation, and pachyderma. Kifafa is a Swahili word meaning "being half-dead and rigid."
Peters plus syndrome
MedGen UID:
163204
Concept ID:
C0796012
Disease or Syndrome
Peters plus syndrome is characterized by anterior chamber eye anomalies, short limbs with broad distal extremities, variable developmental delay/intellectual disability, characteristic facial features, and cleft lip/palate. The most common anterior chamber defect is Peters' anomaly, consisting of central corneal clouding, thinning of the posterior cornea, and iridocorneal adhesions. Cataracts and glaucoma are common. Developmental delay is observed in about 80% of children; while some adults have normal cognitive function, intellectual disability can range from mild to severe. Cleft lip is present in 45% and cleft palate in 33%.
Laband syndrome
MedGen UID:
208656
Concept ID:
C0796013
Disease or Syndrome
Zimmermann-Laband syndrome is a rare disorder characterized by gingival fibromatosis, dysplastic or absent nails, hypoplasia of the distal phalanges, scoliosis, hepatosplenomegaly, hirsutism, and abnormalities of the cartilage of the nose and/or ears (summary by Balasubramanian and Parker, 2010). Genetic Heterogeneity of Zimmermann-Laband Syndrome Zimmermann-Laband syndrome-2 (ZLS2; 616455) is caused by mutation in the ATP6V1B2 gene (606939) on chromosome 8p21.
Lenz microphthalmia syndrome
MedGen UID:
162898
Concept ID:
C0796016
Congenital Abnormality
Lenz microphthalmia syndrome (LMS) is characterized by unilateral or bilateral microphthalmia and/or clinical anophthalmia with malformations of the ears, teeth, fingers, skeleton, and/or genitourinary system. Microphthalmia is often accompanied by microcornea and glaucoma. Coloboma is present in approximately 60% of microphthalmic eyes with severity ranging from isolated iris coloboma to coloboma of the ciliary body, choroid, and optic disk. Ears may be low set, anteverted, posteriorly rotated, simple, cup shaped, or abnormally modeled. Hearing loss has been observed. Dental findings include irregularly shaped, missing, or widely spaced teeth. Duplicated thumbs, syndactyly, clinodactyly, camptodactyly, and microcephaly are common, as are narrow/sloping shoulders, underdeveloped clavicles, kyphoscoliosis, exaggerated lumbar lordosis, long cylindric thorax, and webbed neck. Genitourinary anomalies include hypospadias, cryptorchidism, renal hypoplasia/aplasia, and hydroureter. Approximately 60% of affected males have mild-to-severe intellectual disability or developmental delay.
Lowry Maclean syndrome
MedGen UID:
167095
Concept ID:
C0796020
Disease or Syndrome
Mental deficiency with multiple abnormalities consisting of ocular proptosis, glaucoma, cleft palate, diaphragmatic eventration, cardiovascular defects, growth failure, and craniosynostosis. The originally-reported case was sporadic.
X-linked mental retardation with marfanoid habitus syndrome
MedGen UID:
167096
Concept ID:
C0796022
Disease or Syndrome
The phenotypic spectrum of MED12-related disorders, which is still being defined, includes at a minimum the phenotypes of FG syndrome type 1 (FGS1) and Lujan syndrome (LS). FGS1 and LS share the clinical findings of cognitive impairment, hypotonia, and abnormalities of the corpus callosum. FGS1 is further characterized by absolute or relative macrocephaly, tall forehead, downslanted palpebral fissures, small and simple ears, constipation and/or anal anomalies, broad thumbs and halluces, and characteristic behavior. LS is further characterized by large head, tall thin body habitus, long thin face, high nasal root, high narrow palate, and short philtrum. Carrier females in families with FGS1 and LS are typically unaffected.
Mac Dermot Winter syndrome
MedGen UID:
162900
Concept ID:
C0796024
Disease or Syndrome
A syndrome of prenatal growth deficiency, microcephaly, dysmorphic facies, absent psychomotor development, hypoplastic genitalia, convulsions, and other disorders.
Arts syndrome
MedGen UID:
163205
Concept ID:
C0796028
Disease or Syndrome
Arts syndrome, which is part of the spectrum of PRPS1-related disorders, is characterized by profound congenital sensorineural hearing impairment, early-onset hypotonia, delayed motor development, mild to moderate intellectual disability, ataxia, and increased risk of infection, all of which (with the exception of optic atrophy) present before age two years. Signs of peripheral neuropathy develop during early childhood. Twelve of 15 boys from the two Dutch families reported with Arts syndrome died before age six years of complications of infection. Carrier females can show late-onset (age >20 years) hearing impairment and other findings.
Marden-Walker syndrome
MedGen UID:
163206
Concept ID:
C0796033
Disease or Syndrome
A constellation of immobile facies, blepharophimosis, micrognathia, microcephaly, midfacial hypoplasia, multiple contractures, hypotonia, arachnodactyly, developmental delay, and other anomalies.
Gurrieri syndrome
MedGen UID:
208660
Concept ID:
C0796046
Disease or Syndrome
A syndrome of short stature with retarded bone age, cerebral atrophy, epilepsy, ocular anomalies, skeletal defects, and moderate to severe mental deficiency.
Microphthalmia, syndromic, 7
MedGen UID:
163210
Concept ID:
C0796070
Disease or Syndrome
Microphthalmia with linear skin defects (MLS) syndrome is characterized by unilateral or bilateral microophthalmia and/or anophthalmia and linear skin defects, usually involving the face and neck, which are present at birth and heal with age, leaving minimal residual scarring. Other findings can include central nervous system involvement (e.g., structural anomalies, infantile seizures), developmental delay, heart defects (e.g., hypertrophic cardiomyopathy, oncocytic cardiomyopathy, arrhythmias), short stature, diaphragmatic hernia, nail dystrophy, preauricular pits and hearing loss, and genitourinary malformations. Inter- and intrafamilial variability is considerable.
Myhre syndrome
MedGen UID:
167103
Concept ID:
C0796081
Disease or Syndrome
Myhre syndrome is a rare disorder characterized by mental retardation, dysmorphic facial features, including microcephaly, midface hypoplasia, prognathism, and blepharophimosis, as well as typical skeletal anomalies, including short stature, square body shape, broad ribs, iliac hypoplasia, brachydactyly, flattened vertebrae, and thickened calvaria. Other features, such as congenital heart disease, may also occur. All reported cases have been sporadic (summary by Bachmann-Gagescu et al., 2011).
Megalocornea mental retardation syndrome
MedGen UID:
162904
Concept ID:
C0796086
Disease or Syndrome
Megalocornea and iris anomalies accompanied by facial and skeletal defects, slow psychomotor development, hypotonia, and seizures. Later reports classify megalocornea-mental retardation syndrome into several types: Type 1 Synonym: Neuhauser syndrome With iris hypoplasia and minor abnormalities. Type 2 With camptodactyly, scoliosis, and growth retardation. Type 3 Synonym: Verloes type With macrocephaly, hypotonia, and other minor anomalies but no hypoplasia of the irides. Type 4 With megalocephaly,obesity, and normal irides.
Oculocerebrocutaneous syndrome
MedGen UID:
163214
Concept ID:
C0796092
Disease or Syndrome
Orbital cysts and other eye defects, multiple cerebral anomalies, and focal dermal defects are the principal characteristics of this syndrome.
Mental retardation, congenital heart disease, blepharophimosis, blepharoptosis and hypoplastic teeth
MedGen UID:
162905
Concept ID:
C0796094
Disease or Syndrome
A syndrome of delayed development, blepharophimosis, blepharoptosis, dental hypoplasia, deafness, heart defect, cryptorchidism and scrotal hypoplasia in males, and other abnormalities.
C syndrome
MedGen UID:
167105
Concept ID:
C0796095
Disease or Syndrome
The C syndrome, also known as Opitz trigonocephaly syndrome, is a malformation syndrome characterized by trigonocephaly, severe mental retardation, hypotonia, variable cardiac defects, redundant skin, and dysmorphic facial features, including upslanted palpebral fissures, epicanthal folds, depressed nasal bridge, and low-set, posteriorly rotated ears (summary by Kaname et al., 2007). C syndrome shows phenotypic overlap with Bohring-Opitz syndrome, or C-like syndrome (605039), a disorder with more severe features than C syndrome, caused by heterozygous mutation in the ASXL1 gene (612990) on chromosome 20q11.
Pallister W syndrome
MedGen UID:
163215
Concept ID:
C0796110
Disease or Syndrome
Mental retardation with characteristic pugilistic facies (flat nose, frontal prominence, hypertelorism, downslanting palpebral fissures, and anterior cowlick), midline notch on the upper lip, cleft palate, spasticity, and various musculoskeletal anomalies. The original cases were reported in brothers R. W. and S. W., hence the synonym W syndrome.
Renal hamartomas nephroblastomatosis and fetal gigantism
MedGen UID:
162909
Concept ID:
C0796113
Disease or Syndrome
Perlman syndrome is an autosomal recessive congenital overgrowth syndrome with similarities to Beckwith-Wiedemann syndrome (BWS; 130650). Affected children are large at birth, are hypotonic, and show organomegaly, characteristic facial dysmorphisms (inverted V-shaped upper lip, prominent forehead, deep-set eyes, broad and flat nasal bridge, and low-set ears), renal anomalies (nephromegaly and hydronephrosis), frequent neurodevelopmental delay, and high neonatal mortality. Perlman syndrome is associated with a high risk of Wilms tumor, with a 64% incidence in infants surviving beyond the neonatal period. The tumor is diagnosed at an earlier age in these individuals compared with sporadic cases (less than 2 years and 3-4 years of age, respectively), and there is a high frequency of bilateral tumors (55%). Histologic examination of the kidneys in children with Perlman syndrome shows frequent nephroblastomatosis, which is a precursor lesion for Wilms tumor (summary by Astuti et al., 2012).
Primrose syndrome
MedGen UID:
162911
Concept ID:
C0796121
Disease or Syndrome
Primrose syndrome consists of recognizable facial features, macrocephaly, mental retardation, enlarged and calcified external ears, sparse body hair, and distal muscle wasting (summary by Carvalho and Speck-Martins, 2011). Patients with a deletion syndrome involving 3q13.31 (615433) exhibit features overlapping those of Primrose syndrome.
Proud Levine Carpenter syndrome
MedGen UID:
163217
Concept ID:
C0796124
Disease or Syndrome
Proud syndrome is an X-linked developmental disorder characterized by agenesis of the corpus callosum, severe mental retardation, seizures, and spasticity. Males are severely affected, whereas females may be unaffected or have a milder phenotype (Proud et al., 1992). Proud syndrome is part of a phenotypic spectrum of disorders caused by mutation in the ARX gene comprising a nearly continuous series of developmental disorders ranging from lissencephaly (LISX2; 300215) to Proud syndrome to infantile spasms without brain malformations (EIEE1; 308350) to syndromic (309510) and nonsyndromic (300419) mental retardation (Kato et al., 2004; Wallerstein et al., 2008).
Pseudoprogeria syndrome
MedGen UID:
163218
Concept ID:
C0796125
Disease or Syndrome
A Hallermann-Streiff-like syndrome marked by presenile facies suggesting progeria, absent eyebrows and eyelashes, beaked nose, eye abnormalities, spinal defects, osteoporosis, and other disorders.
Aicardi Goutieres syndrome 1
MedGen UID:
162912
Concept ID:
C0796126
Disease or Syndrome
Most characteristically, Aicardi-Goutières syndrome (AGS) manifests as an early-onset encephalopathy that usually, but not always, results in severe intellectual and physical handicap. A subgroup of infants with AGS present at birth with abnormal neurologic findings, hepatosplenomegaly, elevated liver enzymes, and thrombocytopenia, a picture highly suggestive of congenital infection. Otherwise, most affected infants present at variable times after the first few weeks of life, frequently after a period of apparently normal development. Typically, they demonstrate the subacute onset of a severe encephalopathy characterized by extreme irritability, intermittent sterile pyrexias, loss of skills, and slowing of head growth. Over time, as many as 40% develop chilblain skin lesions on the fingers, toes, and ears. It is becoming apparent that atypical, sometimes milder, cases of AGS exist, and thus the true extent of the phenotype associated with mutation of the AGS-related genes is not yet known. For example, mutation of ADAR has recently been associated with a clinical presentation of acute bilateral striatal necrosis.
Congenital disorder of glycosylation type 2C
MedGen UID:
162913
Concept ID:
C0796132
Disease or Syndrome
Congenital disorders of N-linked glycosylation (abbreviated here as CDG-N-linked), are a group of disorders of N-linked oligosaccharides caused by deficiency in 42 different enzymes in the N-linked synthetic pathway. Most commonly, the disorders begin in infancy; manifestations range from severe developmental delay and hypotonia with multiple organ system involvement to hypoglycemia and protein-losing enteropathy with normal development. However, most types have been described in only a few individuals, and thus understanding of the phenotypes is limited. In PMM2-CDG (CDG-Ia), the most common type reported, the clinical presentation and course are highly variable, ranging from death in infancy to mild involvement in adults.
Ramon Syndrome
MedGen UID:
208669
Concept ID:
C0796133
Disease or Syndrome
A slowly progressive syndrome of cherubic facies (fullness of the cheeks, producing a typical chubby face suggestive of a cherub) maxillary fibrous dysplasia, gingival enlargement, radiolucent lesions of the jaws, seizures, delayed mental development, stunted growth, and other defects. Insulin dependent diabetes mellitus and vascular skin lesions may occur.
Renpenning syndrome 1
MedGen UID:
208670
Concept ID:
C0796135
Disease or Syndrome
Renpenning syndrome is an X-linked mental retardation syndrome with clinically recognizable features. Affected individuals have microcephaly, short stature, small testes, and dysmorphic facies, including tall narrow face, upslanting palpebral fissures, abnormal nasal configuration, cupped ears, and short philtrum. The nose may appear long or bulbous, with overhanging columella. Less consistent manifestations include ocular colobomas, cardiac malformations, cleft palate, and anal anomalies. Stevenson et al. (2005) proposed that the various X-linked mental retardation syndromes due to PQBP1 mutations be combined under the name of Renpenning syndrome.
Acrocallosal syndrome, Schinzel type
MedGen UID:
162915
Concept ID:
C0796147
Disease or Syndrome
Classic Joubert syndrome is characterized by three primary findings: A distinctive cerebellar and brain stem malformation called the molar tooth sign (MTS) . Hypotonia. Developmental delays . Often these findings are accompanied by episodic tachypnea or apnea and/or atypical eye movements. In general, the breathing abnormalities improve with age, truncal ataxia develops over time, and acquisition of gross motor milestones is delayed. Cognitive abilities are variable, ranging from severe intellectual disability to normal. The designation Joubert syndrome and related disorders (JSRD) is used to describe individuals with JS who have additional findings including retinal dystrophy, renal disease, ocular colobomas, occipital encephalocele, hepatic fibrosis, polydactyly, oral hamartomas, and endocrine abnormalities. Both intra- and interfamilial variation are seen.
Simpson-Golabi-Behmel syndrome
MedGen UID:
162917
Concept ID:
C0796154
Disease or Syndrome
Simpson-Golabi-Behmel syndrome type 1 (SGBS1) is characterized by pre- and postnatal macrosomia; distinctive craniofacies (including macrocephaly, coarse facial features, macrostomia, macroglossia, palatal abnormalities); and commonly, mild to severe intellectual disability with or without structural brain anomalies. Other variable findings include supernumerary nipples, diastasis recti/umbilical hernia, congenital heart defects, diaphragmatic hernia, genitourinary defects, and GI anomalies. Skeletal anomalies can include vertebral fusion, scoliosis, rib anomalies, and congenital hip dislocation. Hand anomalies can include large hands and postaxial polydactyly. Affected individuals are at increased risk for embryonal tumors, including Wilms tumor, hepatoblastoma, adrenal neuroblastoma, gonadoblastoma, and hepatocellular carcinoma.
Snyder Robinson syndrome
MedGen UID:
162918
Concept ID:
C0796160
Disease or Syndrome
Snyder-Robinson syndrome (SRS) is an X-linked intellectual disability syndrome characterized by asthenic build, facial dysmorphism with a prominent lower lip, kyphoscoliosis, osteoporosis, and speech abnormalities. Developmental delay usually presents as failure to meet early developmental milestones and then evolves to moderate to profound global intellectual disability (which appears to remain stable over time) and variable motor disability. Asthenic habitus and low muscle mass usually develop during the first year, even in males who are ambulatory. During the first decade, males with SRS develop osteoporosis, resulting in fractures in the absence of trauma.
Toriello Carey syndrome
MedGen UID:
163225
Concept ID:
C0796184
Disease or Syndrome
The Toriello-Carey syndrome is a multiple congenital anomaly disorder with variable systemic manifestations, most commonly including mental retardation, agenesis of the corpus callosum, postnatal growth delay, cardiac defects, usually septal defects, distal limb defects, and urogenital anomalies in affected males. Patients have facial dysmorphic features, micrognathia, including full cheeks, hypertelorism, flattened nasal bridge, anteverted nares, and short neck. Not all features are found in all patients and some patients may have additional features such as anal anomalies or hernias (review by Toriello et al., 2003).
Parkinsonism, early onset with mental retardation
MedGen UID:
208674
Concept ID:
C0796195
Disease or Syndrome
Waisman syndrome is an X-linked recessive neurologic disorder characterized by delayed psychomotor development, intellectual disability, and early-onset Parkinson disease (summary by Wilson et al., 2014).
Wieacker syndrome
MedGen UID:
163227
Concept ID:
C0796200
Disease or Syndrome
Wieacker-Wolff syndrome is a severe X-linked recessive neurodevelopmental disorder affecting the central and peripheral nervous systems. It is characterized by onset of muscle weakness in utero (fetal akinesia). Affected boys are born with severe contractures, known as arthrogryposis, and have delayed motor development, facial and bulbar weakness, characteristic dysmorphic facial features, and skeletal abnormalities, such as hip dislocation, scoliosis, and pes equinovarus. Those that survive infancy show mental retardation. Carrier females may have mild features of the disorder (summary by Hirata et al., 2013).
Wittwer syndrome
MedGen UID:
162921
Concept ID:
C0796202
Disease or Syndrome
Mental retardation with multiple congenital abnormalities consisting of craniofacial anomalies, delayed development, skeletal anomalies, urogenital anomalies, and deformed hands.
Woods syndrome
MedGen UID:
490089
Concept ID:
C0796203
Disease or Syndrome
A craniodigital syndrome of prenatal growth retardation, microcephaly, mental retardation, syndactyly of the fingers, and minor facial anomalies.
Worster Drought syndrome
MedGen UID:
163228
Concept ID:
C0796204
Disease or Syndrome
A syndrome with variable expression characterized by suprabulbar paresis, selective weakness and impairment of movement of the orbicularis oris muscle, tongue, and soft palate, resulting in speech and swallowing difficulty.
Atkin syndrome
MedGen UID:
163230
Concept ID:
C0796206
Disease or Syndrome
Mental retardation 9, X-linked
MedGen UID:
167112
Concept ID:
C0796215
Disease or Syndrome
Nonsyndromic mental retardation.
Mental retardation, X-linked 14
MedGen UID:
163231
Concept ID:
C0796220
Disease or Syndrome
Nonsyndromic mental retardation with inconsistent abnormalities.
Mental retardation 21, X-linked
MedGen UID:
162923
Concept ID:
C0796227
Disease or Syndrome
This form of nonsyndromic X-linked mental retardation is characterized by a spectrum of cognitive neurologic impairments or disabilities ranging from moderate mental retardation to high-functioning autism. Males are typically severely affected, but some carrier females may manifest milder deficits (summary by Piton et al., 2008).
C-like syndrome
MedGen UID:
208678
Concept ID:
C0796232
Disease or Syndrome
Bohring-Opitz syndrome is a malformation syndrome characterized by severe intrauterine growth retardation, poor feeding, profound mental retardation, trigonocephaly, prominent metopic suture, exophthalmos, nevus flammeus of the face, upslanting palpebral fissures, hirsutism, and flexion of the elbows and wrists with deviation of the wrists and metacarpophalangeal joints (summary by Hoischen et al., 2011). See also the C syndrome (211750), a disorder with a similar phenotype caused by heterozygous mutation in the CD96 gene (606037) on chromosome 3q13.
Mental retardation 30, X-linked
MedGen UID:
163235
Concept ID:
C0796237
Disease or Syndrome
Nonsyndromic mental retardation with microcephaly, restlessness, and hyperactivity.
Partington X-linked mental retardation syndrome
MedGen UID:
163237
Concept ID:
C0796250
Disease or Syndrome
Partington syndrome is an X-linked developmental disorder characterized by mental retardation and variable movement disturbances. Partington syndrome is part of a phenotypic spectrum of disorders caused by mutation in the ARX gene comprising a nearly continuous series of developmental disorders ranging from hydranencephaly and lissencephaly (LISX2; 300215) to Proud syndrome (300004) to infantile spasms without brain malformations (EIEE1; 308350) to nonsyndromic mental retardation (300419). Although males with ARX mutations are often more severely affected, female mutation carriers may also be affected (Kato et al., 2004; Wallerstein et al., 2008).
Mental retardation X-linked syndromic 5
MedGen UID:
162924
Concept ID:
C0796254
Disease or Syndrome
Pettigrew syndrome is characterized by mental retardation and highly variable additional features, including choreoathetosis, hydrocephalus, Dandy-Walker malformation, seizures, and iron or calcium deposition in the brain, both between and within families (summary by Cacciagli et al., 2014). See 311510 for another X-linked mental retardation syndrome associated with basal ganglia disease (Waisman syndrome). See 220219 for another mental retardation syndrome with Dandy-Walker malformation.
Brooks Wisniewski Brown syndrome
MedGen UID:
208682
Concept ID:
C0796272
Disease or Syndrome
Mental retardation associated with delayed growth and a distinct facial appearance marked by a triangular shape, bifrontal narrowness, malar flatness, blepharophimosis, deeply set eyes, epicanthus inversus, bulbous nose, low hairline, malformed ears, ill-defined philtrum, and thin tented upper lip.
Acromegaloid facial appearance syndrome
MedGen UID:
167116
Concept ID:
C0796280
Disease or Syndrome
Coarse (acromegaloid) facies with thick lips, overgrowth of the intraoral mucosa, blepharophimosis, and bulbous nose in association with dull mentality and other disorders.
Oculodentodigital dysplasia
MedGen UID:
167236
Concept ID:
C0812437
Disease or Syndrome
Oculodentodigital syndrome is characterized by a typical facial appearance and variable involvement of the eyes, dentition, and fingers. Characteristic facial features include a narrow, pinched nose with hypoplastic alae nasi, prominent columella and thin anteverted nares together with a narrow nasal bridge, and prominent epicanthic folds giving the impression of hypertelorism. The teeth are usually small and carious. Typical eye findings include microphthalmia and microcornea. The characteristic digital malformation is complete syndactyly of the fourth and fifth fingers (syndactyly type III) but the third finger may be involved and associated camptodactyly is a common finding (summary by Judisch et al., 1979). Neurologic abnormalities are sometimes associated (Gutmann et al., 1991), and lymphedema has been reported in some patients with ODDD (Brice et al., 2013). See review by De Bock et al. (2013). Genetic Heterogeneity of Oculodentodigital Syndrome An autosomal recessive form of ODDD (257850) is also caused by mutation in the GJA1 gene, but the majority of cases are autosomal dominant.
6-pyruvoyl-tetrahydropterin synthase deficiency
MedGen UID:
209234
Concept ID:
C0878676
Disease or Syndrome
Tetrahydrobiopterin (BH4)-deficient hyperphenylalaninemia (HPA) comprises a genetically heterogeneous group of progressive neurologic disorders caused by autosomal recessive mutations in the genes encoding enzymes involved in the synthesis or regeneration of BH4. BH4 is a cofactor for phenylalanine hydroxylase (PAH; 612349), tyrosine hydroxylase (TH; 191290) and tryptophan hydroxylase (TPH1; 191060), the latter 2 of which are involved in neurotransmitter synthesis. The BH4-deficient HPAs are characterized phenotypically by hyperphenylalaninemia, depletion of the neurotransmitters dopamine and serotonin, and progressive cognitive and motor deficits (Dudesek et al., 2001). HPABH4A, caused by mutations in the PTS gene, represents the most common cause of BH4-deficient hyperphenylalaninemia (Dudesek et al., 2001). Other forms of BH4-deficient HPA include HPABH4B (233910), caused by mutation in the GCH1 gene (600225), HPABH4C (261630), caused by mutation in the QDPR gene (612676), and HPABH4D (264070), caused by mutation in the PCBD1 gene (126090). Niederwieser et al. (1982) noted that about 1 to 3% of patients with hyperphenylalaninemia have one of these BH4-deficient forms. These disorders are clinically and genetically distinct from classic phenylketonuria (PKU; 261600), caused by mutation in the PAH gene. Two additional disorders associated with BH4 deficiency and neurologic symptoms do not have overt hyperphenylalaninemia as a feature: dopa-responsive dystonia (612716), caused by mutation in the SPR gene (182125), and autosomal dominant dopa-responsive dystonia (DYT5; 128230), caused by mutation in the GCH1 gene. Patients with these disorders may develop hyperphenylalaninemia when stressed.
Sialic acid storage disease, severe infantile type
MedGen UID:
203367
Concept ID:
C1096902
Disease or Syndrome
The allelic disorders of free sialic acid metabolism — Salla disease, intermediate severe Salla disease, and infantile free sialic acid storage disease (ISSD) — are neurodegenerative disorders resulting from increased lysosomal storage of free sialic acid. The mildest phenotype is Salla disease, which is characterized by normal appearance and neurologic findings at birth followed by slowly progressive neurologic deterioration resulting in mild to moderate psychomotor retardation, spasticity, athetosis, and epileptic seizures. The most severe phenotype is ISSD, characterized by severe developmental delay, coarse facial features, hepatosplenomegaly, and cardiomegaly; death usually occurs in early childhood.
Salla disease
MedGen UID:
203368
Concept ID:
C1096903
Disease or Syndrome
The allelic disorders of free sialic acid metabolism — Salla disease, intermediate severe Salla disease, and infantile free sialic acid storage disease (ISSD) — are neurodegenerative disorders resulting from increased lysosomal storage of free sialic acid. The mildest phenotype is Salla disease, which is characterized by normal appearance and neurologic findings at birth followed by slowly progressive neurologic deterioration resulting in mild to moderate psychomotor retardation, spasticity, athetosis, and epileptic seizures. The most severe phenotype is ISSD, characterized by severe developmental delay, coarse facial features, hepatosplenomegaly, and cardiomegaly; death usually occurs in early childhood.
Merosin deficient congenital muscular dystrophy
MedGen UID:
224728
Concept ID:
C1263858
Disease or Syndrome
Congenital muscular dystrophy (CMD) is a clinically and genetically heterogeneous group of inherited muscle disorders. Muscle weakness typically presents from birth to early infancy. Affected infants typically appear "floppy" with low muscle tone and poor spontaneous movements. Affected children may present with delay or arrest of gross motor development together with joint and/or spinal rigidity. Muscle weakness may improve, worsen, or stabilize in the short term; however, with time progressive weakness and joint contractures, spinal deformities, and respiratory compromise may affect quality of life and life span. The main CMD subtypes, grouped by involved protein function and gene in which causative mutations occur, are laminin alpha-2 (merosin) deficiency (MDC1A), collagen VI-deficient CMD, the dystroglycanopathies (caused by mutations in POMT1, POMT2, FKTN, FKRP, LARGE, POMGNT1, and ISPD), SEPN1-related CMD (previously known as rigid spine syndrome, RSMD1) and LMNA-related CMD (L-CMD). Several less known CMD subtypes have been reported in a limited number of individuals. Cognitive impairment ranging from intellectual disability to mild cognitive delay, structural brain and/or eye abnormalities, and seizures are found almost exclusively in the dystroglycanopathies while white matter abnormalities without major cognitive involvement tend to be seen in the laminin alpha-2-deficient subtype.
Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy
MedGen UID:
266127
Concept ID:
C1272305
Disease or Syndrome
CADASIL (cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy) is characterized by mid-adult onset of recurrent ischemic stroke, cognitive decline progressing to dementia, a history of migraine with aura, mood disturbance, apathy, and diffuse white matter lesions and subcortical infarcts on neuroimaging.
Cardio-facio-cutaneous syndrome
MedGen UID:
266149
Concept ID:
C1275081
Disease or Syndrome
Cardiofaciocutaneous (CFC) syndrome is characterized by cardiac abnormalities (pulmonic stenosis and other valve dysplasias, septal defects, hypertrophic cardiomyopathy, rhythm disturbances), distinctive craniofacial appearance, and cutaneous abnormalities (including xerosis, hyperkeratosis, ichthyosis, keratosis pilaris, ulerythema ophryogenes, eczema, pigmented moles, hemangiomas, and palmoplantar hyperkeratosis). The hair is typically sparse, curly, fine or thick, woolly or brittle; eyelashes and eyebrows may be absent or sparse. Nails may be dystrophic or fast growing. Some form of neurologic and/or cognitive delay (ranging from mild to severe) is seen in all affected individuals. Neoplasia, mostly acute lymphoblastic leukemia (ALL), has been reported in some individuals.
Hereditary neurocutaneous angiomata
MedGen UID:
226898
Concept ID:
C1275084
Neoplastic Process
Deficiency of glycerate kinase
MedGen UID:
226941
Concept ID:
C1291386
Disease or Syndrome
D-glyceric aciduria is a very rare autosomal recessive metabolic disorder with a highly variable phenotype. Some patients have an encephalopathic presentation, with severe mental retardation, seizures, microcephaly, and sometimes early death, while others have a mild phenotype with only mild speech delay or even normal development (summary by Sass et al., 2010).
Deficiency of phosphoserine phosphatase
MedGen UID:
452940
Concept ID:
C1291463
Disease or Syndrome
Deficiency of ribose-5-phosphate isomerase
MedGen UID:
220946
Concept ID:
C1291609
Disease or Syndrome
Nicolaides-Baraitser syndrome
MedGen UID:
220983
Concept ID:
C1303073
Disease or Syndrome
Nicolaides-Baraitser syndrome (NCBRS) is characterized by severe mental retardation, early-onset seizures, short stature, dysmorphic facial features, and sparse hair (summary by Sousa et al., 2009).
Oral-facial-digital syndrome
MedGen UID:
307142
Concept ID:
C1510460
Disease or Syndrome
Oral-facial-digital syndrome type I (OFD1) is associated with dysfunction of primary cilia and is characterized by the following abnormalities: Oral (lobed tongue, hamartomas or lipomas of the tongue, cleft of the hard or soft palate, accessory gingival frenulae, hypodontia, and other dental abnormalities). Facial (widely spaced eyes or telecanthus, hypoplasia of the alae nasi, median cleft or pseudocleft upper lip, micrognathia) . Digital (brachydactyly, syndactyly of varying degrees, and clinodactyly of the fifth finger; duplicated hallux [great toe]; preaxial or postaxial polydactyly of the hands). Brain (intracerebral cysts, corpus callosum agenesis, cerebellar agenesis with or without Dandy-Walker malformation) . Kidney (polycystic kidney disease). As many as 50% of individuals with OFD1 have some degree of intellectual disability, which is usually mild. Almost all affected individuals are female. However, males with OFD1 have been described, mostly as malformed fetuses delivered by women with OFD1.
Nephrogenic diabetes insipidus, X-linked
MedGen UID:
288785
Concept ID:
C1563705
Disease or Syndrome
Nephrogenic diabetes insipidus (NDI) is characterized by inability to concentrate the urine, which results in polyuria (excessive urine production) and polydipsia (excessive thirst). Affected untreated infants usually have poor feeding and failure to thrive, and rapid onset of severe dehydration with illness, hot environment, or the withholding of water. Short stature and secondary dilatation of the ureters and bladder from the high urine volume is common in untreated individuals.
Nephrogenic diabetes insipidus, autosomal
MedGen UID:
289643
Concept ID:
C1563706
Disease or Syndrome
Nephrogenic diabetes insipidus (NDI) is characterized by inability to concentrate the urine, which results in polyuria (excessive urine production) and polydipsia (excessive thirst). Affected untreated infants usually have poor feeding and failure to thrive, and rapid onset of severe dehydration with illness, hot environment, or the withholding of water. Short stature and secondary dilatation of the ureters and bladder from the high urine volume is common in untreated individuals.
Catecholaminergic polymorphic ventricular tachycardia
MedGen UID:
351513
Concept ID:
C1631597
Disease or Syndrome
Catecholaminergic polymorphic ventricular tachycardia (CPVT) is characterized by episodic syncope occurring during exercise or acute emotion in individuals without structural cardiac abnormalities. Arrhythmias may be well tolerated, with only mild symptoms such as dizziness or lypothymia. The underlying cause of these episodes is the onset of fast ventricular tachycardia (bidirectional or polymorphic). Spontaneous recovery occurs when these arrhythmias self-terminate. In other instances, ventricular tachycardia may degenerate into ventricular fibrillation and cause sudden death if cardiopulmonary resuscitation is not readily available. The mean age of onset of symptoms (usually a syncopal episode) of CPVT is between age seven and twelve years; onset as late as the fourth decade of life has been reported. If untreated, CPVT is highly lethal, as approximately 30% of affected individuals experience at least one cardiac arrest and up to 80% one or more syncopal spells. Sudden death may be the first manifestation of the disease.
Episodic ataxia type 1
MedGen UID:
318554
Concept ID:
C1719788
Disease or Syndrome
Episodic ataxia type 1 (EA1) is a potassium channelopathy characterized by constant myokymia and dramatic episodes of spastic contractions of the skeletal muscles of the head, arms, and legs with loss of both motor coordination and balance. During attacks individuals may experience a number of variable symptoms including vertigo, blurred vision, diplopia, nausea, headache, diaphoresis, clumsiness, stiffening of the body, dysarthric speech, and difficulty in breathing, among others. EA1 may be associated with epilepsy. Other findings can include delayed motor development, cognitive disability, choreoathetosis, and carpal spasm. Usually, onset is in childhood or early adolescence.
Peroxisome biogenesis disorders, Zellweger syndrome spectrum
MedGen UID:
330407
Concept ID:
C1832200
Disease or Syndrome
Peroxisome biogenesis disorders, Zellweger syndrome spectrum (PBD, ZSS) is a continuum of three phenotypes — Zellweger syndrome (ZS), the most severe; neonatal adrenoleukodystrophy (NALD); and infantile Refsum disease (IRD), the least severe — that were originally described before the biochemical and molecular bases of these disorders had been fully determined. Individuals with PBD, ZSS usually come to clinical attention in the newborn period or later in childhood. In the newborn period, affected children are hypotonic, feed poorly, and have distinctive facies, seizures, and liver cysts with hepatic dysfunction. Bony stippling (chondrodysplasia punctata) of the patella(e) and other long bones may occur. Infants with ZS are significantly impaired and typically die during the first year of life, usually having made no developmental progress. Older children have retinal dystrophy, sensorineural hearing loss, developmental delay with hypotonia, and liver dysfunction. The clinical courses of NALD and IRD are variable and may include developmental delays, hearing loss, vision impairment, liver dysfunction, episodes of hemorrhage, and intracranial bleeding. While some children can be very hypotonic, others learn to walk and talk. The condition is often slowly progressive.
Microcephaly, corpus callosum dysgenesis and cleft lip-palate
MedGen UID:
330448
Concept ID:
C1832369
Disease or Syndrome
Cold-induced sweating syndrome
MedGen UID:
321950
Concept ID:
C1832409
Disease or Syndrome
Crisponi syndrome, the infantile presentation of cold-induced sweating syndrome (CISS), is characterized by dysmorphic features (distinctive facies; lower facial weakness; flexion deformity at the elbows; camptodactyly with fisted hands; misshapen feet and overriding toes); poor suck reflex and severely impaired swallowing; and often temperature spikes with increased risk of seizures and sudden death. During the first decade of life, children with CISS develop profuse sweating of their face, arms, and chest with ambient temperatures below 18º to 22º C and often with other stimuli including apprehension or ingestion of sweets. Affected individuals sweat very little in hot environments and may feel overheated. In the second decade, progressive thoracolumbar kyphoscoliosis requires intervention.
Mental retardation, microcephaly, epilepsy, and coarse face
MedGen UID:
330468
Concept ID:
C1832437
Disease or Syndrome
Potocki-Shaffer syndrome
MedGen UID:
318657
Concept ID:
C1832588
Disease or Syndrome
Potocki-Shaffer syndrome is a rare contiguous gene deletion syndrome due to haploinsufficiency of the 11p12-p11.2 region and is characterized by craniofacial abnormalities, developmental delay, intellectual disability, multiple exostoses (168500), and biparietal foramina (605957) (summary by Swarr et al., 2010).
Alopecia-mental retardation syndrome with convulsions and hypergonadotropic hypogonadism
MedGen UID:
321990
Concept ID:
C1832593
Disease or Syndrome
Hypoparathyroidism familial isolated
MedGen UID:
322005
Concept ID:
C1832648
Disease or Syndrome
Garfield and Karaplis (2001) reviewed the various causes and clinical forms of hypoparathyroidism. They noted that hypoparathyroidism is a clinical disorder characterized by hypocalcemia and hyperphosphatemia. It manifests when parathyroid hormone (PTH; 168450) secreted from the parathyroid glands is insufficient to maintain normal extracellular fluid calcium concentrations or, less commonly, when PTH is unable to function optimally in target tissues, despite adequate circulating levels. Congenital absence of the parathyroid and thymus glands (III and IV pharyngeal pouch syndrome, or DiGeorge syndrome, 188400) is usually a sporadic condition (Taitz et al., 1966).
Congenital disorder of glycosylation type 1D
MedGen UID:
322026
Concept ID:
C1832736
Disease or Syndrome
Congenital disorders of N-linked glycosylation (abbreviated here as CDG-N-linked), are a group of disorders of N-linked oligosaccharides caused by deficiency in 42 different enzymes in the N-linked synthetic pathway. Most commonly, the disorders begin in infancy; manifestations range from severe developmental delay and hypotonia with multiple organ system involvement to hypoglycemia and protein-losing enteropathy with normal development. However, most types have been described in only a few individuals, and thus understanding of the phenotypes is limited. In PMM2-CDG (CDG-Ia), the most common type reported, the clinical presentation and course are highly variable, ranging from death in infancy to mild involvement in adults.
Cataracts, congenital, with sensorineural deafness, down syndrome-like facial appearance, short stature, and mental retardation
MedGen UID:
371416
Concept ID:
C1832812
Disease or Syndrome
Ayme-Gripp syndrome is a clinically homogeneous phenotype characterized by congenital cataracts, sensorineural hearing loss, intellectual disability, seizures, brachycephaly, a distinctive flat facial appearance, and reduced growth (Niceta et al., 2015).
Focal epilepsy with speech disorder with or without mental retardation
MedGen UID:
322043
Concept ID:
C1832814
Disease or Syndrome
Focal epilepsy with speech disorder is a childhood-onset seizure disorder with a highly variable phenotype. Seizures typically occur in the temporal lobe, or rolandic brain region, which affects speech and language, and electroencephalogram (EEG) characteristically shows centrotemporal spike-wave discharges. EEG abnormalities often occur during sleep and may manifest as continuous spike-wave discharges during slow-wave sleep (CSWS or CSWSS). FESD represents an electroclinical spectrum that ranges from severe early-onset seizures associated with delayed psychomotor development, persistent speech difficulties, and mental retardation to a more benign entity characterized by childhood onset of mild or asymptomatic seizures associated with transient speech difficulties followed by remission of seizures in adolescence and normal psychomotor development. There is incomplete penetrance and intrafamilial variability, even among family members who carry the same GRIN2A mutation (summary by Lesca et al., 2013; Lemke et al., 2013; Carvill et al., 2013). The disorder represented here encompasses several clinical entities, including Landau-Kleffner syndrome (LKS), epileptic encephalopathy with continuous spike and wave during slow-wave sleep (ECSWS; CSWSS), autosomal dominant rolandic epilepsy, mental retardation, and speech dyspraxia (ADRESD; RESDAD), and benign epilepsy with centrotemporal spikes (BECTS; see 117100). LKS is classically described as a childhood-onset variant of epileptic aphasia. It is associated with EEG abnormalities occurring in the temporal lobe of the language-dominant hemisphere, even in the absence of overt clinical seizures. LKS is sometimes referred to as an 'acquired aphasia' because most affected children show normal psychomotor development until the onset of seizures, usually between 3 and 7 years, although some may have prior delayed development. A hallmark of the disorder is severe impairment in auditory language comprehension and speech. Some patients may also have persistent intellectual disability or behavioral abnormalities reminiscent of autism or attention deficit-hyperactivity disorder. EEG abnormalities typically include centrotemporal spikes suggestive of rolandic epilepsy or continuous spike and waves during slow-wave sleep. The presence of CSWS is associated with more widespread behavioral and cognitive regression than LKS, although the 2 disorders may be considered part of a spectrum. There is controversy about the precise definition of LKS and its relationship to CSWS that stems mainly from the phenotypic heterogeneity of the disorder (summary by Stefanatos, 2011).
Familial hemiplegic migraine type 1
MedGen UID:
331389
Concept ID:
C1832894
Disease or Syndrome
Familial hemiplegic migraine (FHM) falls within the category of migraine with aura. In migraine with aura (including familial hemiplegic migraine) the neurologic symptoms of aura are unequivocally localizable to the cerebral cortex or brain stem and include visual disturbance (most common), sensory loss (e.g., numbness or paresthesias of the face or an extremity), and dysphasia (difficulty with speech); FHM must include motor involvement, i.e., hemiparesis (weakness of an extremity). Hemiparesis occurs with at least one other symptom during FHM aura. Neurologic deficits with FHM attacks can be prolonged for hours to days and may outlast the associated migrainous headache. FHM is often earlier in onset than typical migraine, frequently beginning in the first or second decade; the frequency of attacks tends to decrease with age. Approximately 40%-50% of families with FHM1 have cerebellar signs ranging from nystagmus to progressive, usually late-onset mild ataxia. Cerebral infarction and death have rarely been associated with hemiplegic migraine.
Permanent neonatal diabetes mellitus
MedGen UID:
371484
Concept ID:
C1833104
Disease or Syndrome
Nonsyndromic permanent neonatal diabetes mellitus (PNDM) is characterized by the onset of hyperglycemia within the first six months of life (mean age: 7 weeks; range: birth to 26 weeks) that does not resolve over time. Clinical manifestations at the time of diagnosis include intrauterine growth retardation (IUGR), hyperglycemia, glycosuria, osmotic polyuria, severe dehydration, and failure to thrive. Therapy with insulin corrects the hyperglycemia and allows for catch-up growth. The course of PNDM varies by genotype. Pancreatic agenesis/hypoplasia caused by homozygous mutations in PDX1 results in severe insulin deficiency and exocrine pancreatic insufficiency.
Dermoid cysts, familial frontonasal
MedGen UID:
371575
Concept ID:
C1833473
Disease or Syndrome
Carnitine palmitoyltransferase II deficiency, infantile
MedGen UID:
322211
Concept ID:
C1833511
Disease or Syndrome
Carnitine palmitoyltransferase II (CPT II) deficiency is a disorder of long-chain fatty-acid oxidation. The three clinical presentations are: lethal neonatal form, severe infantile hepatocardiomuscular form, and myopathic form (which is usually mild and can manifest from infancy to adulthood). While the former two are severe multisystemic diseases characterized by liver failure with hypoketotic hypoglycemia, cardiomyopathy, seizures, and early death, the latter is characterized by exercise-induced muscle pain and weakness, sometimes associated with myoglobinuria. The myopathic form of CPT II deficiency is the most common disorder of lipid metabolism affecting skeletal muscle and is the most frequent cause of hereditary myoglobinuria. Males are more likely to be affected than females.
CARNITINE PALMITOYLTRANSFERASE II DEFICIENCY, LETHAL NEONATAL
MedGen UID:
318896
Concept ID:
C1833518
Disease or Syndrome
Carnitine palmitoyltransferase II (CPT II) deficiency is a disorder of long-chain fatty-acid oxidation. The three clinical presentations are: lethal neonatal form, severe infantile hepatocardiomuscular form, and myopathic form (which is usually mild and can manifest from infancy to adulthood). While the former two are severe multisystemic diseases characterized by liver failure with hypoketotic hypoglycemia, cardiomyopathy, seizures, and early death, the latter is characterized by exercise-induced muscle pain and weakness, sometimes associated with myoglobinuria. The myopathic form of CPT II deficiency is the most common disorder of lipid metabolism affecting skeletal muscle and is the most frequent cause of hereditary myoglobinuria. Males are more likely to be affected than females.
Ceroid lipofuscinosis neuronal 4B autosomal dominant
MedGen UID:
320287
Concept ID:
C1834207
Disease or Syndrome
The neuronal ceroid-lipofuscinoses (NCLs) are a group of inherited, neurodegenerative, lysosomal storage disorders characterized by progressive intellectual and motor deterioration, seizures, and early death. Visual gvhmloss is a feature of most forms. Clinical phenotypes have been characterized traditionally according to the age of onset and order of appearance of clinical features into infantile, late-infantile, juvenile, adult, and Northern epilepsy (also known as progressive epilepsy with mental retardation [EPMR]). There is however genetic and allelic heterogeneity; a proposed new nomenclature and classification system has been developed to take into account both the responsible gene and the age at disease onset; for example, CLN1 disease, infantile onset and CLN1 disease, juvenile onset are both caused by mutations in PPT1 but with differing age of onset. The most prevalent NCLs are CLN3 disease, classic juvenile and CLN2 disease, classic late infantile (although prevalence varies by ethnicity and country of family origin): CLN2 disease, classic late infantile. The first symptoms typically appear between age two and four years, usually starting with epilepsy, followed by regression of developmental milestones, myoclonic ataxia, and pyramidal signs. Visual impairment typically appears at age four to six years and rapidly progresses to light /dark awareness only. Life expectancy ranges from age six years to early teenage. CLN3 disease, classic juvenile. Onset is usually between ages four and ten years. Rapidly progressing visual loss resulting in severe visual impairment within one to two years is often the first clinical sign. Epilepsy with generalized tonic-clonic seizures and/or complex-partial seizures typically appears around age ten years. Life expectancy ranges from the late teens to the 30s. Other forms of NCL may present with behavior changes, epilepsy, visual impairment, or slowing of developmental progress and then loss of skills. The course may be extremely variable. Some genotype-phenotype information is available.
Jankovic Rivera syndrome
MedGen UID:
371854
Concept ID:
C1834569
Disease or Syndrome
Spinal muscular atrophy with progressive myoclonic epilepsy is an autosomal recessive neuromuscular disorder characterized by childhood onset of proximal muscle weakness and generalized muscular atrophy due to degeneration of spinal motor neurons, followed by the onset of myoclonic seizures. The disorder is progressive, and usually results in loss of ambulation and early death from respiratory insufficiency (summary by Zhou et al., 2012).
Myoclonus, cerebellar ataxia, and deafness
MedGen UID:
331780
Concept ID:
C1834579
Disease or Syndrome
Holoprosencephaly 2
MedGen UID:
322517
Concept ID:
C1834877
Disease or Syndrome
Holoprosencephaly (HPE) is a structural anomaly of the brain in which there is failed or incomplete separation of the forebrain early in gestation. Classic HPE encompasses a continuum of brain malformations including (in order of decreasing severity): alobar, semilobar, lobar, and middle interhemispheric variant (MIHV) type HPE; a septopreoptic type has also been described. Other CNS abnormalities not specific to HPE may also occur. HPE is accompanied by a spectrum of characteristic craniofacial anomalies in approximately 80% of individuals with HPE. Developmental delay is present in virtually all individuals with the HPE spectrum of CNS anomalies. Seizures and pituitary dysfunction are common. Most affected fetuses do not survive; severely affected children typically do not survive beyond early infancy, while a significant proportion of more mildly affected children survive past 12 months. Mildly manifesting individuals without appreciable brain anomalies on conventional neuroimaging may be described as having “microform” HPE.
Hypomagnesemia 2, renal
MedGen UID:
320542
Concept ID:
C1835171
Disease or Syndrome
Microcephaly with or without chorioretinopathy, lymphedema, or mental retardation
MedGen UID:
320559
Concept ID:
C1835265
Disease or Syndrome
Microcephaly with or without chorioretinopathy, lymphedema, or mental retardation is an autosomal dominant disorder that involves an overlapping but variable spectrum of central nervous system and ocular developmental anomalies. Microcephaly ranges from mild to severe and is often associated with mild to moderate developmental delay and a characteristic facial phenotype with upslanting palpebral fissures, broad nose with rounded tip, long philtrum with thin upper lip, prominent chin, and prominent ears. Chorioretinopathy is the most common eye abnormality, but retinal folds, microphthalmia, and myopic and hypermetropic astigmatism have also been reported, and some individuals have no overt ocular phenotype. Congenital lymphedema, when present, is typically confined to the dorsa of the feet, and lymphoscintigraphy reveals the absence of radioactive isotope uptake from the webspaces between the toes (summary by Ostergaard et al., 2012). Robitaille et al. (2014) found that MCLMR includes a broader spectrum of ocular disease, including retinal detachment with avascularity of the peripheral retina, and noted phenotypic overlap with familial exudative vitreoretinopathy (FEVR; see EVR1, 133780). An autosomal recessive form of microcephaly with chorioretinopathy (251270) is caused by mutation in the TUBGCP6 gene (610053) on chromosome 22q. See also Mirhosseini-Holmes-Walton syndrome (autosomal recessive microcephaly with pigmentary retinopathy and mental retardation; 268050), which has been mapped to chromosome 8q21.3-q22.1. A patient with microcephaly, congenital retinal fold, mental retardation, and lymphedema who had a pericentric inversion of chromosome 6 resulting in haploinsufficiency of the CDK19 gene (614720) has been reported.
Hyperekplexia hereditary
MedGen UID:
332019
Concept ID:
C1835614
Disease or Syndrome
Hereditary hyperekplexia (HPX) is characterized by generalized stiffness immediately after birth that normalizes during the first years of life; excessive startle reflex (eye blinking and a flexor spasm of the trunk) to unexpected (particularly auditory) stimuli; and a short period of generalized stiffness following the startle response during which voluntary movements are impossible. Exaggerated head-retraction reflex (HRR) consisting of extension of the head followed by violent flexor spasms of limbs and neck muscles elicited by tapping the tip of the nose is observed in most children. Other findings include periodic limb movements in sleep (PLMS) and hypnagogic (occurring when falling asleep) myoclonus. Sudden infant death (SIDS) has been reported. Intellect is usually normal; mild intellectual disability may occur.
Holoprosencephaly 9
MedGen UID:
324369
Concept ID:
C1835819
Disease or Syndrome
Holoprosencephaly (HPE) is a structural anomaly of the brain in which there is failed or incomplete separation of the forebrain early in gestation. Classic HPE encompasses a continuum of brain malformations including (in order of decreasing severity): alobar, semilobar, lobar, and middle interhemispheric variant (MIHV) type HPE; a septopreoptic type has also been described. Other CNS abnormalities not specific to HPE may also occur. HPE is accompanied by a spectrum of characteristic craniofacial anomalies in approximately 80% of individuals with HPE. Developmental delay is present in virtually all individuals with the HPE spectrum of CNS anomalies. Seizures and pituitary dysfunction are common. Most affected fetuses do not survive; severely affected children typically do not survive beyond early infancy, while a significant proportion of more mildly affected children survive past 12 months. Mildly manifesting individuals without appreciable brain anomalies on conventional neuroimaging may be described as having “microform” HPE.
Congenital disorder of glycosylation type 1M
MedGen UID:
332072
Concept ID:
C1835849
Disease or Syndrome
Congenital disorders of N-linked glycosylation (abbreviated here as CDG-N-linked), are a group of disorders of N-linked oligosaccharides caused by deficiency in 42 different enzymes in the N-linked synthetic pathway. Most commonly, the disorders begin in infancy; manifestations range from severe developmental delay and hypotonia with multiple organ system involvement to hypoglycemia and protein-losing enteropathy with normal development. However, most types have been described in only a few individuals, and thus understanding of the phenotypes is limited. In PMM2-CDG (CDG-Ia), the most common type reported, the clinical presentation and course are highly variable, ranging from death in infancy to mild involvement in adults.
Epilepsy, nocturnal frontal lobe, type 4
MedGen UID:
332082
Concept ID:
C1835905
Disease or Syndrome
Autosomal dominant nocturnal frontal lobe epilepsy (ADNFLE) is characterized by clusters of nocturnal motor seizures, which are often stereotyped and brief (5 seconds to 5 minutes). They vary from simple arousals from sleep to dramatic, often bizarre, hyperkinetic events with tonic or dystonic features. Affected individuals may experience aura. Retained awareness during seizures is common. A minority of individuals experience daytime seizures. Onset ranges from infancy to adulthood. About 80% of individuals develop ADNFLE in the first two decades of life; mean age of onset is ten years. Clinical neurologic examination is normal and intellect is usually preserved, but reduced intellect, psychiatric comorbidity, or cognitive deficits may occur. Within a family, the manifestations of the disorder may vary considerably. ADNFLE is lifelong but not progressive. As an individual reaches middle age, attacks may become milder and less frequent.
Aminoacylase 1 deficiency
MedGen UID:
324393
Concept ID:
C1835922
Disease or Syndrome
Aminoacylase-1 deficiency (ACY1D) is a rare autosomal recessive inborn error of metabolism characterized by increased urinary excretion of specific N-actyl amino acids. Most patients show neurologic abnormalities such as intellectual disability, seizures, hypotonia, and motor delay (summary by Ferri et al., 2014).
Cerebral dysgenesis, neuropathy, ichthyosis, and palmoplantar keratoderma syndrome
MedGen UID:
332113
Concept ID:
C1836033
Disease or Syndrome
CEDNIK (cerebral dysgenesis, neuropathy, ichthyosis, and keratoderma) syndrome refers to a unique constellation of clinical manifestations including microcephaly, severe neurologic impairment, psychomotor retardation, failure to thrive, and facial dysmorphism, as well as palmoplantar keratoderma and late-onset ichthyosis. Brain magnetic resonance imaging (MRI) shows various degrees of cerebral dysgenesis including absence of corpus callosum and cortical dysplasia. The syndrome has been found to be uniformly fatal between the ages of 5 and 12 years (Fuchs-Telem et al., 2011).
Goldberg-Shprintzen megacolon syndrome
MedGen UID:
332131
Concept ID:
C1836123
Disease or Syndrome
Goldberg-Shprintzen syndrome is an autosomal recessive multiple congenital anomaly syndrome characterized by intellectual disability, microcephaly, and dysmorphic facial features. Most patients also have Hirschsprung disease and/or gyral abnormalities of the brain, consistent with defects in migration of neural crest cells and neurons. Other features, such as megalocornea or urogenital anomalies, may also be present. Goldberg-Shprintzen syndrome has some resemblance to Mowat-Wilson syndrome (MOWS; 235730) but is genetically distinct (summary by Drevillon et al., 2013). Yomo et al. (1991) referred to this disorder as Goldberg-Shprintzen syndrome, which should not be confused with Shprintzen-Goldberg craniosynostosis syndrome (182212) or 2 other Shprintzen syndromes (192430, 182210).
Cerebrorenodigital syndrome with limb malformations and triradiate acetabula
MedGen UID:
373053
Concept ID:
C1836287
Disease or Syndrome
Rhabdoid tumor predisposition syndrome 1
MedGen UID:
322892
Concept ID:
C1836327
Neoplastic Process
The rhabdoid tumor predisposition syndrome is an autosomal dominant cancer syndrome predisposing to renal or extrarenal malignant rhabdoid tumors and to a variety of tumors of the central nervous system, including choroid plexus carcinoma, medulloblastoma, and central primitive neuroectodermal tumors (Sevenet et al., 1999). Rhabdoid tumors are a highly malignant group of neoplasms that usually occur in children less than 2 years of age. Malignant rhabdoid tumors (MRTs) of the kidney were first described as a sarcomatous variant of Wilms tumors (Beckwith and Palmer, 1978). Later, extrarenal rhabdoid tumor was reported in numerous locations, including the central nervous system (CNS) (Parham et al., 1994). Classification has been difficult because of considerable variation in the histologic and immunologic characteristics within and between rhabdoid tumors of the liver, soft tissues, and CNS. In the CNS, rhabdoid tumors may be pure rhabdoid tumors or a variant that has been designated atypical teratoid tumor (AT/RT).
Autosomal dominant progressive external ophthalmoplegia with mitochondrial DNA deletions 3
MedGen UID:
373087
Concept ID:
C1836439
Disease or Syndrome
Progressive external ophthalmoplegia is characterized by multiple mitochondrial DNA deletions in skeletal muscle. The most common clinical features include adult onset of weakness of the external eye muscles and exercise intolerance. Patients with C10ORF2-linked adPEO may have other clinical features including proximal muscle weakness, ataxia, peripheral neuropathy, cardiomyopathy, cataracts, depression, and endocrine abnormalities (summary by Fratter et al., 2010). For a general phenotypic description and a discussion of genetic heterogeneity of autosomal dominant progressive external ophthalmoplegia, see PEOA1 (157640). PEO caused by mutations in the POLG gene are associated with more complicated phenotypes than those forms caused by mutations in the SLC25A4 (103220) or C10ORF2 genes (Lamantea et al., 2002).
Schindler disease, type 1
MedGen UID:
373113
Concept ID:
C1836544
Disease or Syndrome
Alpha-N-acetylgalactosaminidase (NAGA) deficiency is a very rare lysosomal storage disorder. It is clinically heterogeneous with 3 main phenotypes: type I is an infantile-onset neuroaxonal dystrophy; type II, also known as Kanzaki disease (609242), is an adult-onset disorder characterized by angiokeratoma corporis diffusum and mild intellectual impairment; and type III is an intermediate disorder with mild to moderate neurologic manifestations (Desnick and Schindler, 2001).
Congenital disorder of glycosylation type 1F
MedGen UID:
322968
Concept ID:
C1836669
Disease or Syndrome
Congenital disorders of glycosylation (CDGs) are metabolic deficiencies in glycoprotein biosynthesis that usually cause severe mental and psychomotor retardation. Different forms of CDGs can be recognized by altered isoelectric focusing (IEF) patterns of serum transferrin. For a general discussion of CDGs, see CDG Ia (212065) and CDG Ib (602579).
Peripheral demyelinating neuropathy, central dysmyelination, Waardenburg syndrome, and Hirschsprung disease
MedGen UID:
373160
Concept ID:
C1836727
Disease or Syndrome
The neurologic variant of Waardenburg-Shah syndrome is a complex neurocristopathy that includes features of 4 distinct syndromes: peripheral demyelinating neuropathy (see 118200), central dysmyelination, Waardenburg syndrome, and Hirschsprung disease (see 142623) (Inoue et al., 2004). Inoue et al. (2004) proposed the acronym PCWH for this disorder.
Diabetes mellitus, permanent neonatal, with cerebellar agenesis
MedGen UID:
332288
Concept ID:
C1836780
Disease or Syndrome
Ceroid lipofuscinosis neuronal 9
MedGen UID:
332304
Concept ID:
C1836841
Disease or Syndrome
The neuronal ceroid-lipofuscinoses (NCLs) are a group of inherited, neurodegenerative, lysosomal storage disorders characterized by progressive intellectual and motor deterioration, seizures, and early death. Visual gvhmloss is a feature of most forms. Clinical phenotypes have been characterized traditionally according to the age of onset and order of appearance of clinical features into infantile, late-infantile, juvenile, adult, and Northern epilepsy (also known as progressive epilepsy with mental retardation [EPMR]). There is however genetic and allelic heterogeneity; a proposed new nomenclature and classification system has been developed to take into account both the responsible gene and the age at disease onset; for example, CLN1 disease, infantile onset and CLN1 disease, juvenile onset are both caused by mutations in PPT1 but with differing age of onset. The most prevalent NCLs are CLN3 disease, classic juvenile and CLN2 disease, classic late infantile (although prevalence varies by ethnicity and country of family origin): CLN2 disease, classic late infantile. The first symptoms typically appear between age two and four years, usually starting with epilepsy, followed by regression of developmental milestones, myoclonic ataxia, and pyramidal signs. Visual impairment typically appears at age four to six years and rapidly progresses to light /dark awareness only. Life expectancy ranges from age six years to early teenage. CLN3 disease, classic juvenile. Onset is usually between ages four and ten years. Rapidly progressing visual loss resulting in severe visual impairment within one to two years is often the first clinical sign. Epilepsy with generalized tonic-clonic seizures and/or complex-partial seizures typically appears around age ten years. Life expectancy ranges from the late teens to the 30s. Other forms of NCL may present with behavior changes, epilepsy, visual impairment, or slowing of developmental progress and then loss of skills. The course may be extremely variable. Some genotype-phenotype information is available.
Mental retardation with optic atrophy, facial dysmorphism, microcephaly, and short stature
MedGen UID:
324635
Concept ID:
C1836915
Disease or Syndrome
Emanuel syndrome
MedGen UID:
323030
Concept ID:
C1836929
Disease or Syndrome
Emanuel syndrome is characterized by severe intellectual disability, microcephaly, failure to thrive, preauricular tags or pits, ear anomalies, cleft or high-arched palate, micrognathia, kidney abnormalities, congenital heart defects, and genital abnormalities in males.
Cleft palate, isolated
MedGen UID:
332392
Concept ID:
C1837218
Finding
Cleft palate as an isolated malformation behaves as an entity distinct from cleft lip with or without cleft palate (see 119530). Dominantly inherited cleft soft palate in 4 generations has been reported (Jenkins and Stady, 1980); see 119570.
Leukodystrophy, hypomyelinating, 2
MedGen UID:
325157
Concept ID:
C1837355
Disease or Syndrome
Congenital disorder of glycosylation type 1E
MedGen UID:
324784
Concept ID:
C1837396
Disease or Syndrome
Congenital disorders of glycosylation (CDGs) are metabolic deficiencies in glycoprotein biosynthesis that usually cause severe mental and psychomotor retardation. Different forms of CDGs can be recognized by altered isoelectric focusing (IEF) patterns of serum transferrin. For a general discussion of CDGs, see CDG Ia (212065) and CDG Ib (602579).
Pyruvate dehydrogenase phosphatase deficiency
MedGen UID:
332448
Concept ID:
C1837429
Disease or Syndrome
Pyruvate dehydrogenase deficiency is characterized by the buildup of a chemical called lactic acid in the body and a variety of neurological problems. Signs and symptoms of this condition usually first appear shortly after birth, and they can vary widely among affected individuals. The most common feature is a potentially life-threatening buildup of lactic acid (lactic acidosis), which can cause nausea, vomiting, severe breathing problems, and an abnormal heartbeat. People with pyruvate dehydrogenase deficiency usually have neurological problems as well. Most have delayed development of mental abilities and motor skills such as sitting and walking. Other neurological problems can include intellectual disability, seizures, weak muscle tone (hypotonia), poor coordination, and difficulty walking. Some affected individuals have abnormal brain structures, such as underdevelopment of the tissue connecting the left and right halves of the brain (corpus callosum), wasting away (atrophy) of the exterior part of the brain known as the cerebral cortex, or patches of damaged tissue (lesions) on some parts of the brain. Because of the severe health effects, many individuals with pyruvate dehydrogenase deficiency do not survive past childhood, although some may live into adolescence or adulthood.
Congenital disorder of glycosylation type 1L
MedGen UID:
324794
Concept ID:
C1837438
Disease or Syndrome
Congenital disorders of N-linked glycosylation (abbreviated here as CDG-N-linked), are a group of disorders of N-linked oligosaccharides caused by deficiency in 42 different enzymes in the N-linked synthetic pathway. Most commonly, the disorders begin in infancy; manifestations range from severe developmental delay and hypotonia with multiple organ system involvement to hypoglycemia and protein-losing enteropathy with normal development. However, most types have been described in only a few individuals, and thus understanding of the phenotypes is limited. In PMM2-CDG (CDG-Ia), the most common type reported, the clinical presentation and course are highly variable, ranging from death in infancy to mild involvement in adults.
Epilepsy, idiopathic generalized 3
MedGen UID:
373335
Concept ID:
C1837468
Disease or Syndrome
Primary autosomal recessive microcephaly 5
MedGen UID:
373344
Concept ID:
C1837501
Disease or Syndrome
Primary autosomal recessive microcephalies (MCPH) and Seckel syndrome (SCKS) spectrum disorders are characterized by microcephaly and the absence of visceral malformations. Although MCHP and SCKS were previously distinguished by height (maximum height in SCKS was equivalent to the minimum height in MCPH), stature is no longer a discriminating feature, leading to the conclusion that these phenotypes constitute a spectrum rather than distinct entities. Microcephaly is characterized by: Onset during the second trimester of gestation; Occipito-frontal head circumference (OFC) at birth equal to or less than -2 SD below the mean for sex, age, and ethnicity; Slower than average increase in OFC after birth. Variable findings in the MCPH-SCKS spectrum disorders include: Brain structure (which is normal in the majority); Degree of cognitive impairment (usually mild to moderate without significant motor delay in the majority of persons with MCPH and more severe in those with SCKS and MCPH with brain malformations); Degree of short stature; Craniosynostosis (which may be secondary to poor brain growth).
AICAR transformylase/IMP cyclohydrolase deficiency
MedGen UID:
332474
Concept ID:
C1837530
Disease or Syndrome
Congenital disorder of glycosylation type 1K
MedGen UID:
332969
Concept ID:
C1837896
Disease or Syndrome
Congenital disorders of N-linked glycosylation (abbreviated here as CDG-N-linked), are a group of disorders of N-linked oligosaccharides caused by deficiency in 42 different enzymes in the N-linked synthetic pathway. Most commonly, the disorders begin in infancy; manifestations range from severe developmental delay and hypotonia with multiple organ system involvement to hypoglycemia and protein-losing enteropathy with normal development. However, most types have been described in only a few individuals, and thus understanding of the phenotypes is limited. In PMM2-CDG (CDG-Ia), the most common type reported, the clinical presentation and course are highly variable, ranging from death in infancy to mild involvement in adults.
Epilepsy, nocturnal frontal lobe, type 1
MedGen UID:
324932
Concept ID:
C1838049
Disease or Syndrome
Autosomal dominant nocturnal frontal lobe epilepsy (ADNFLE) is characterized by clusters of nocturnal motor seizures, which are often stereotyped and brief (5 seconds to 5 minutes). They vary from simple arousals from sleep to dramatic, often bizarre, hyperkinetic events with tonic or dystonic features. Affected individuals may experience aura. Retained awareness during seizures is common. A minority of individuals experience daytime seizures. Onset ranges from infancy to adulthood. About 80% of individuals develop ADNFLE in the first two decades of life; mean age of onset is ten years. Clinical neurologic examination is normal and intellect is usually preserved, but reduced intellect, psychiatric comorbidity, or cognitive deficits may occur. Within a family, the manifestations of the disorder may vary considerably. ADNFLE is lifelong but not progressive. As an individual reaches middle age, attacks may become milder and less frequent.
Cleft palate, cardiac defect, genital anomalies, and ectrodactyly
MedGen UID:
324947
Concept ID:
C1838121
Disease or Syndrome
Brachydactyly-Mental Retardation syndrome
MedGen UID:
373895
Concept ID:
C1838126
Disease or Syndrome
2q37 microdeletion syndrome is characterized by mild-moderate developmental delay/intellectual disability, brachymetaphalangy of digits 3-5 (often digit 4 alone) (>50%), short stature, obesity, hypotonia, characteristic facial appearance, autism or autism spectrum disorder (30%), joint hypermobility/dislocation, and scoliosis. Other findings include seizures (20%-35%), congenital heart disease, CNS abnormalities (hydrocephalus, dilated ventricles), umbilical/inguinal hernia, tracheomalacia, situs abnormalities, gastrointestinal abnormalities, and renal malformations. Wilms tumor has been reported in two individuals.
Hereditary hemorrhagic telangiectasia type 2
MedGen UID:
324960
Concept ID:
C1838163
Disease or Syndrome
Hereditary hemorrhagic telangiectasia (HHT) is characterized by the presence of multiple arteriovenous malformations (AVMs) that lack intervening capillaries and result in direct connections between arteries and veins. Although HHT is a developmental disorder and infants are occasionally severely affected, in most people the features are age-dependent and the diagnosis not suspected until adolescence or later. Small AVMs (or telangiectases) close to the surface of the skin and mucous membranes often rupture and bleed after slight trauma. The most common clinical manifestation is spontaneous and recurrent nosebleeds (epistaxis) beginning on average at age 12 years. Approximately 25% of individuals with HHT have GI bleeding, which most commonly begins after age 50 years. Large AVMs often cause symptoms when they occur in the brain, liver, or lungs; complications from bleeding or shunting may be sudden and catastrophic.
CODAS syndrome
MedGen UID:
333031
Concept ID:
C1838180
Disease or Syndrome
CODAS is an acronym for cerebral, ocular, dental, auricular, and skeletal anomalies. CODAS syndrome is a rare disorder characterized by a distinctive constellation of features that includes developmental delay, craniofacial anomalies, cataracts, ptosis, median nasal groove, delayed tooth eruption, hearing loss, short stature, delayed epiphyseal ossification, metaphyseal hip dysplasia, and vertebral coronal clefts (summary by Strauss et al., 2015).
Spastic paraplegia 6
MedGen UID:
324965
Concept ID:
C1838192
Disease or Syndrome
Band heterotopia of brain
MedGen UID:
333046
Concept ID:
C1838239
Disease or Syndrome
Fryns macrocephaly
MedGen UID:
373933
Concept ID:
C1838281
Disease or Syndrome
Oculoectodermal syndrome
MedGen UID:
333068
Concept ID:
C1838329
Disease or Syndrome
Pachygyria with mental retardation and seizures
MedGen UID:
333107
Concept ID:
C1838491
Disease or Syndrome
This autosomal recessive neurodevelopmental disorder is characterized by pachygyria, mental retardation, seizures, and diffuse localization of arachnoid cysts. It most likely represents a neuronal migration disorder within the lissencephaly spectrum (summary by Guzel et al., 2007).
Ceroid lipofuscinosis neuronal 8
MedGen UID:
374004
Concept ID:
C1838570
Disease or Syndrome
The neuronal ceroid-lipofuscinoses (NCLs) are a group of inherited, neurodegenerative, lysosomal storage disorders characterized by progressive intellectual and motor deterioration, seizures, and early death. Visual gvhmloss is a feature of most forms. Clinical phenotypes have been characterized traditionally according to the age of onset and order of appearance of clinical features into infantile, late-infantile, juvenile, adult, and Northern epilepsy (also known as progressive epilepsy with mental retardation [EPMR]). There is however genetic and allelic heterogeneity; a proposed new nomenclature and classification system has been developed to take into account both the responsible gene and the age at disease onset; for example, CLN1 disease, infantile onset and CLN1 disease, juvenile onset are both caused by mutations in PPT1 but with differing age of onset. The most prevalent NCLs are CLN3 disease, classic juvenile and CLN2 disease, classic late infantile (although prevalence varies by ethnicity and country of family origin): CLN2 disease, classic late infantile. The first symptoms typically appear between age two and four years, usually starting with epilepsy, followed by regression of developmental milestones, myoclonic ataxia, and pyramidal signs. Visual impairment typically appears at age four to six years and rapidly progresses to light /dark awareness only. Life expectancy ranges from age six years to early teenage. CLN3 disease, classic juvenile. Onset is usually between ages four and ten years. Rapidly progressing visual loss resulting in severe visual impairment within one to two years is often the first clinical sign. Epilepsy with generalized tonic-clonic seizures and/or complex-partial seizures typically appears around age ten years. Life expectancy ranges from the late teens to the 30s. Other forms of NCL may present with behavior changes, epilepsy, visual impairment, or slowing of developmental progress and then loss of skills. The course may be extremely variable. Some genotype-phenotype information is available.
Puerto rican infant hypotonia syndrome
MedGen UID:
333148
Concept ID:
C1838651
Disease or Syndrome
Pancreatic agenesis and congenital heart disease
MedGen UID:
325509
Concept ID:
C1838780
Disease or Syndrome
Wolfram syndrome, mitochondrial form
MedGen UID:
325511
Concept ID:
C1838782
Disease or Syndrome
Neuropathy ataxia retinitis pigmentosa syndrome
MedGen UID:
325131
Concept ID:
C1838914
Disease or Syndrome
Mitochondrial diseases are a clinically heterogeneous group of disorders that arise as a result of dysfunction of the mitochondrial respiratory chain. They can be caused by mutation of genes encoded by either nuclear DNA or mitochondrial DNA (mtDNA). While some mitochondrial disorders only affect a single organ (e.g., the eye in Leber hereditary optic neuropathy [LHON]), many involve multiple organ systems and often present with prominent neurologic and myopathic features. Mitochondrial disorders may present at any age. Many individuals with a mutation of mtDNA display a cluster of clinical features that fall into a discrete clinical syndrome, such as the Kearns-Sayre syndrome (KSS), chronic progressive external ophthalmoplegia (CPEO), mitochondrial encephalomyopathy with lactic acidosis and stroke-like episodes (MELAS), myoclonic epilepsy with ragged-red fibers (MERRF), neurogenic weakness with ataxia and retinitis pigmentosa (NARP), or Leigh syndrome (LS). However, considerable clinical variability exists and many individuals do not fit neatly into one particular category, which is well-illustrated by the overlapping spectrum of disease phenotypes (including mitochondrial recessive ataxia syndrome (MIRAS) resulting from mutation of the nuclear gene POLG, which has emerged as a major cause of mitochondrial disease. Common clinical features of mitochondrial disease – whether involving a mitochondrial or nuclear gene – include ptosis, external ophthalmoplegia, proximal myopathy and exercise intolerance, cardiomyopathy, sensorineural deafness, optic atrophy, pigmentary retinopathy, and diabetes mellitus. Common central nervous system findings are fluctuating encephalopathy, seizures, dementia, migraine, stroke-like episodes, ataxia, and spasticity. A high incidence of mid- and late pregnancy loss is a common occurrence that often goes unrecognized.
Mitochondrial complex I deficiency
MedGen UID:
374101
Concept ID:
C1838979
Disease or Syndrome
Isolated complex I deficiency is the most common enzymatic defect of the oxidative phosphorylation disorders (McFarland et al., 2004; Kirby et al., 2004). It causes a wide range of clinical disorders, ranging from lethal neonatal disease to adult-onset neurodegenerative disorders. Phenotypes include macrocephaly with progressive leukodystrophy, nonspecific encephalopathy, hypertrophic cardiomyopathy, myopathy, liver disease, Leigh syndrome (256000), Leber hereditary optic neuropathy (535000), and some forms of Parkinson disease (see 556500) (Loeffen et al., 2000; Pitkanen et al., 1996; Robinson, 1998). Genetic Heterogeneity of Complex I Deficiency Mitochondrial complex I deficiency shows extreme genetic heterogeneity and can be caused by mutation in nuclear-encoded genes or in mitochondrial-encoded genes. There are no obvious genotype-phenotype correlations, and inference of the underlying basis from the clinical or biochemical presentation is difficult, if not impossible (summary by Haack et al., 2012). However, the majority of cases are caused by mutations in nuclear-encoded genes (Loeffen et al., 2000; Triepels et al., 2001). Complex I deficiency with autosomal recessive inheritance results from mutation in nuclear-encoded subunit genes, including NDUFV1 (161015), NDUFV2 (600532), NDUFS1 (157655), NDUFS2 (602985), NDUFS3 (603846), NDUFS4 (602694), NDUFS6 (603848), NDUFS7 (601825), NDUFS8 (602141), NDUFA2 (602137), NDUFA11 (612638), NDUFAF3 (612911), NDUFA10 (603835), NDUFB3 (603839), NDUFB9 (601445), and the complex I assembly genes B17.2L (609653), HRPAP20 (611776), C20ORF7 (612360), NUBPL (613621), and NDUFAF1 (606934). The disorder can also be caused by mutation in other nuclear-encoded genes, including FOXRED1 (613622), ACAD9 (611103; see 611126), and MTFMT (611766; see 256000). X-linked inheritance is observed with mutations in the NDUFA1 gene (300078). Complex I deficiency with mitochondrial inheritance has been associated with mutation in 6 mitochondrial-encoded components of complex I: MTND1 (516000), MTND2 (516001), MTND3 (516002), MTND4 (516003), MTND5 (516005), MTND6 (516006). Most of these patients have a phenotype of Leber hereditary optic neuropathy (LHON; 535000) or Leigh syndrome (256000). Features of complex I deficiency may also be caused by mutation in other mitochondrial genes, including MTTS2 (590085).
Hunter Rudd Hoffmann syndrome
MedGen UID:
374138
Concept ID:
C1839125
Congenital Abnormality
Trigonocephaly, short stature, and retarded psychomotor development.
Pyruvate dehydrogenase E1-alpha deficiency
MedGen UID:
326487
Concept ID:
C1839414
Disease or Syndrome
Prieto X-linked mental retardation syndrome
MedGen UID:
374294
Concept ID:
C1839730
Disease or Syndrome
Mental retardation syndrome with facial abnormalities, subcortical cerebral atrophy, defective tooth development, skin dimples at the lower back, lower limb defects, clinodactyly, luxation of the patella, and eye abnormalities.
Wilson-Turner X-linked mental retardation syndrome
MedGen UID:
333393
Concept ID:
C1839736
Disease or Syndrome
WTS is an X-linked neurologic disorder characterized by severe intellectual disability, dysmorphic facial features, hypogonadism, short stature, and truncal obesity. Affected females have a milder phenotype than affected males (summary by Harakalova et al., 2012).
Mental retardation, X-linked, syndromic 12
MedGen UID:
333405
Concept ID:
C1839792
Disease or Syndrome
Mental retardation and psoriasis
MedGen UID:
333408
Concept ID:
C1839801
Disease or Syndrome
Corpus callosum, partial agenesis of, X-linked
MedGen UID:
374339
Concept ID:
C1839909
Disease or Syndrome
L1 syndrome is an inherited disorder that primarily affects the nervous system. L1 syndrome involves a variety of features that were once thought to be distinct disorders, but are now considered to be part of the same syndrome. The most common characteristics of L1 syndrome are muscle stiffness (spasticity) of the lower limbs, intellectual disability, increased fluid in the center of the brain (hydrocephalus), and thumbs bent toward the palm (adducted thumbs). People with L1 syndrome can also have difficulty speaking (aphasia), seizures, and underdeveloped or absent tissue connecting the left and right halves of the brain (agenesis of the corpus callosum). The symptoms of L1 syndrome vary widely among affected individuals, even among members of the same family. Because this disorder involves spasticity of the lower limbs, L1 syndrome is sometimes referred to as spastic paraplegia type 1 (SPG1).
IFAP syndrome with or without BRESHECK syndrome
MedGen UID:
327007
Concept ID:
C1839988
Disease or Syndrome
The IFAP/BRESHECK syndrome is an X-linked multiple congenital anomaly disorder with variable severity. The classic triad, which defines IFAP, is ichthyosis follicularis, atrichia, and photophobia. Some patients have additional features, including mental retardation, brain anomalies, Hirschsprung disease, corneal opacifications, kidney dysplasia, cryptorchidism, cleft palate, and skeletal malformations, particularly of the vertebrae, which constitutes BRESHECK syndrome (summary by Naiki et al., 2012).
Ichthyosis and male hypogonadism
MedGen UID:
333456
Concept ID:
C1839989
Disease or Syndrome
Single upper central incisor
MedGen UID:
326686
Concept ID:
C1840235
Disease or Syndrome
Barakat syndrome
MedGen UID:
374443
Concept ID:
C1840333
Disease or Syndrome
Giant pigmented hairy nevus
MedGen UID:
330752
Concept ID:
C1842036
Neoplastic Process
Congenital melanocytic nevus syndrome is characterized by pigmentary skin defects apparent at birth. Most individuals have 1 or more large or giant lesions greater than 20 cm and up to over 60 cm in diameter, which may cover up to 80% of total body area. These lesions may or may not be hairy. Smaller 'satellite' pigmented lesions numbering in the hundreds may also be present all over the body. Congenital melanocytic nevi (CMN) can be associated with malignant melanoma (see CMM1, 155600), but the risk appears to be low, ranging from 1 to 2% for all individuals, but rising to 10 to 15% in those with very large nevi (greater than 40 cm). A small subset of patients with CMNS have abnormalities of the central nervous system, known as 'neurocutaneous melanosis' or 'neuromelanosis' (249400), which may be symptomatic. Patients with CMNS also tend to have a characteristic facial appearance, including wide or prominent forehead, periorbital fullness, small short nose with narrow nasal bridge, round face, full cheeks, prominent premaxilla, and everted lower lip (summary by Kinsler et al., 2008; Kinsler et al., 2012). Spitz nevi are benign melanocytic melanomas composed of epithelioid or spindle cell melanocytes. They usually present as solitary skin tumors but can occur in multiple patterns, having agminated, dermatomal, and disseminated forms (summary by Sarin et al., 2013). Nevus spilus, also known as speckled lentiginous nevus, is a congenital hyperpigmented patch that progressively evolves, with affected individuals developing dark macules and papules during childhood and adolescence. Over time, nevus spilus may give rise to common lentigines, melanocytic nevi, Spitz nevi, and melanomas (summary by Sarin et al., 2014).
Lipodystrophy, generalized, with mental retardation, deafness, short stature, and slender bones
MedGen UID:
334166
Concept ID:
C1842465
Disease or Syndrome
Uniparental disomy, paternal, chromosome 14
MedGen UID:
330856
Concept ID:
C1842466
Disease or Syndrome
Heterotopia, periventricular, autosomal recessive
MedGen UID:
334110
Concept ID:
C1842563
Disease or Syndrome
Periventricular heterotopia is a condition in which nerve cells (neurons) do not migrate properly during the early development of the fetal brain, from about the 6th week to the 24th week of pregnancy. Heterotopia means "out of place." In normal brain development, neurons form in the periventricular region, located around fluid-filled cavities (ventricles) near the center of the brain. The neurons then migrate outward to form the exterior of the brain (cerebral cortex) in six onion-like layers. In periventricular heterotopia, some neurons fail to migrate to their proper position and form clumps around the ventricles. Periventricular heterotopia usually becomes evident when seizures first appear, often during the teenage years. The nodules around the ventricles are then typically discovered when magnetic resonance imaging (MRI) studies are done. Affected individuals usually have normal intelligence, although some have mild intellectual disability. Difficulty with reading and spelling (dyslexia) has been reported in some people with periventricular heterotopia. Less commonly, individuals with periventricular heterotopia may have more severe brain malformations, small head size (microcephaly), developmental delays, recurrent infections, blood vessel abnormalities, or other problems. Periventricular heterotopia may also occur in association with other conditions such as Ehlers-Danlos syndrome, which results in extremely flexible joints, skin that stretches easily, and fragile blood vessels.
Congenital disorder of glycosylation type 1J
MedGen UID:
334113
Concept ID:
C1842572
Disease or Syndrome
Congenital disorders of N-linked glycosylation (abbreviated here as CDG-N-linked), are a group of disorders of N-linked oligosaccharides caused by deficiency in 42 different enzymes in the N-linked synthetic pathway. Most commonly, the disorders begin in infancy; manifestations range from severe developmental delay and hypotonia with multiple organ system involvement to hypoglycemia and protein-losing enteropathy with normal development. However, most types have been described in only a few individuals, and thus understanding of the phenotypes is limited. In PMM2-CDG (CDG-Ia), the most common type reported, the clinical presentation and course are highly variable, ranging from death in infancy to mild involvement in adults.
Autism 3
MedGen UID:
334211
Concept ID:
C1842632
Finding
Autism, the prototypic pervasive developmental disorder (PDD), is usually apparent by 3 years of age. It is characterized by a triad of limited or absent verbal communication, a lack of reciprocal social interaction or responsiveness, and restricted, stereotypic, and ritualized patterns of interests and behavior (Bailey et al., 1996; Risch et al., 1999). 'Autism spectrum disorder,' sometimes referred to as ASD, is a broader phenotype encompassing the less severe disorders Asperger syndrome (see ASPG1; 608638) and pervasive developmental disorder, not otherwise specified (PDD-NOS). 'Broad autism phenotype' includes individuals with some symptoms of autism, but who do not meet the full criteria for autism or other disorders. Mental retardation coexists in approximately two-thirds of individuals with ASD, except for Asperger syndrome, in which mental retardation is conspicuously absent (Jones et al., 2008). Genetic studies in autism often include family members with these less stringent diagnoses (Schellenberg et al., 2006). For a discussion of genetic heterogeneity of autism, see 209850. See also chromosome 13q14 deletion syndrome (613884) in which retinoblastoma and mental retardation are features.
Pontocerebellar hypoplasia type 3
MedGen UID:
334225
Concept ID:
C1842687
Disease or Syndrome
Pontocerebellar hypoplasia (PCH) refers to a heterogeneous group of disorders characterized by an abnormally small cerebellum and brainstem. Clinical features vary, but usually include severe developmental delay, dysmorphic features, seizures, and early death (summary by Durmaz et al., 2009). For a phenotypic description and a discussion of genetic heterogeneity of PCH, see PCH1 (607596).
Gaucher disease, perinatal lethal
MedGen UID:
374996
Concept ID:
C1842704
Disease or Syndrome
Gaucher disease (GD) encompasses a continuum of clinical findings from a perinatal lethal disorder to an asymptomatic type. The identification of three major clinical types (1, 2, and 3) and two other subtypes (perinatal-lethal and cardiovascular) is useful in determining prognosis and management. GD type 1 is characterized by the presence of clinical or radiographic evidence of bone disease (osteopenia, focal lytic or sclerotic lesions, and osteonecrosis), hepatosplenomegaly, anemia and thrombocytopenia, lung disease, and the absence of primary central nervous system disease. GD types 2 and 3 are characterized by the presence of primary neurologic disease; in the past, they were distinguished by age of onset and rate of disease progression, but these distinctions are not absolute. Disease with onset before age two years, limited psychomotor development, and a rapidly progressive course with death by age two to four years is classified as GD type 2. Individuals with GD type 3 may have onset before age two years, but often have a more slowly progressive course, with survival into the third or fourth decade. The perinatal-lethal form is associated with ichthyosiform or collodion skin abnormalities or with nonimmune hydrops fetalis. The cardiovascular form is characterized by calcification of the aortic and mitral valves, mild splenomegaly, corneal opacities, and supranuclear ophthalmoplegia. Cardiopulmonary complications have been described with all the clinical subtypes, although varying in frequency and severity.
Congenital disorder of glycosylation type 1I
MedGen UID:
334618
Concept ID:
C1842836
Disease or Syndrome
Congenital disorders of N-linked glycosylation (abbreviated here as CDG-N-linked), are a group of disorders of N-linked oligosaccharides caused by deficiency in 42 different enzymes in the N-linked synthetic pathway. Most commonly, the disorders begin in infancy; manifestations range from severe developmental delay and hypotonia with multiple organ system involvement to hypoglycemia and protein-losing enteropathy with normal development. However, most types have been described in only a few individuals, and thus understanding of the phenotypes is limited. In PMM2-CDG (CDG-Ia), the most common type reported, the clinical presentation and course are highly variable, ranging from death in infancy to mild involvement in adults.
Chromosome 1p36 deletion syndrome
MedGen UID:
334629
Concept ID:
C1842870
Disease or Syndrome
1p36 deletion syndrome is characterized by typical craniofacial features consisting of straight eyebrows, deeply set eyes, midface retrusion, wide and depressed nasal bridge, long philtrum, pointed chin, large, late-closing anterior fontanel (77%), microbrachycephaly (65%), epicanthal folds (50%), and posteriorly rotated, low-set, abnormal ears. Other characteristic findings include brachy/camptodactyly and short feet. Developmental delay/intellectual disability of variable degree are present in all, and hypotonia in 95%. Seizures occur in 44%-58% of affected individuals. Other findings include structural brain abnormalities (88%), congenital heart defects (71%), eye/vision problems (52%), hearing loss (47%), skeletal anomalies (41%), abnormalities of the external genitalia (25%), and renal abnormalities (22%).
Alzheimer disease, type 3
MedGen UID:
334304
Concept ID:
C1843013
Disease or Syndrome
Alzheimer disease (AD) is characterized by adult-onset progressive dementia associated with cerebral cortical atrophy, beta-amyloid plaque formation, and intraneuronal neurofibrillary tangles. AD typically begins with subtle memory failure that becomes more severe and is eventually incapacitating. Other common findings include confusion, poor judgment, language disturbance, agitation, withdrawal, hallucinations, seizures, Parkinsonian features, increased muscle tone, myoclonus, incontinence, and mutism. Familial AD (FAD) characterizes families that have more than one member with AD and usually implies multiple affected persons in more than one generation. Early-onset FAD (EOFAD) refers to families in which onset is consistently before age 60 to 65 years and often before age 55 years.
Niemann-Pick disease type C2
MedGen UID:
335942
Concept ID:
C1843366
Disease or Syndrome
Niemann-Pick disease type C (NPC) is a lipid storage disease that can present in infants, children, or adults. Neonates can present with ascites and severe liver disease from infiltration of the liver and/or respiratory failure from infiltration of the lungs. Other infants, without liver or pulmonary disease, have hypotonia and developmental delay. The classic presentation occurs in mid-to-late childhood with the insidious onset of ataxia, vertical supranuclear gaze palsy (VSGP), and dementia. Dystonia and seizures are common. Dysarthria and dysphagia eventually become disabling, making oral feeding impossible; death usually occurs in the late second or third decade from aspiration pneumonia. Adults are more likely to present with dementia or psychiatric symptoms.
Brain small vessel disease with hemorrhage
MedGen UID:
375217
Concept ID:
C1843512
Disease or Syndrome
The spectrum of COL4A1-related disorders includes: small-vessel brain disease of varying severity variably associated with porencephaly, cerebral aneurysms, eye defects (retinal arterial tortuosity, Axenfeld-Rieger anomaly, cataract) and systemic findings (kidney involvement, muscle cramps, Raynaud phenomenon, and cardiac arrhythmia). On imaging studies, small-vessel brain disease is manifest as diffuse periventricular leukoencephalopathy, lacunar infarcts, microhemorrhage, dilated perivascular spaces, and deep intracerebral hemorrhages. Clinically, small-vessel brain disease manifests as infantile hemiparesis, seizures, single or recurrent hemorrhagic stroke, ischemic stroke, and isolated migraine with aura. Porencephaly (fluid-filled cavities in the brain detected by CT or MRI) is typically manifest as infantile hemiparesis, seizures, and intellectual disability; however, on occasion it can be an incidental finding. Hereditary angiopathy with nephropathy, aneurysms, and muscle cramps (HANAC) syndrome usually associates asymptomatic small-vessel brain disease, cerebral large vessel involvement (i.e., aneurysms), and systemic findings involving the kidney, muscle, and small vessels of the eye.
Basal ganglia disease, biotin-responsive
MedGen UID:
375289
Concept ID:
C1843807
Congenital Abnormality
Biotin-thiamine-responsive basal ganglia disease (BTBGD) is characterized by recurrent subacute encephalopathy manifest as confusion, seizures, ataxia, dystonia, supranuclear facial palsy, external ophthalmoplegia, and/or dysphagia which - if left untreated - can eventually lead to coma and even death. Dystonia and cogwheel rigidity are nearly always present; hyperreflexia, ankle clonus, and Babinski responses are common. Hemiparesis or quadriparesis may be seen. Episodes are often triggered by febrile illness or mild trauma or surgery. Less frequently, BTBGD presents as chronic or slowly progressive dystonia, seizures, and/or psychomotor delay. Although onset is usually in childhood (ages three to ten 10 years), it is extremely variable, ranging from the newborn period to adulthood. Prompt administration of biotin and thiamine early in the disease course results in partial or complete improvement within days.
Sensory ataxic neuropathy, dysarthria, and ophthalmoparesis
MedGen UID:
375302
Concept ID:
C1843851
Disease or Syndrome
POLG-related disorders comprise a continuum of overlapping phenotypes that were clinically defined long before their molecular basis was known. These phenotypes exemplify the diversity that can result from mutation of a given gene. Most affected individuals have some, but not all, of the features of a given phenotype; nonetheless, the following nomenclature can assist the clinician in diagnosis and management. Onset of the POLG-related disorders ranges from infancy to late adulthood. Alpers-Huttenlocher syndrome (AHS), one of the most severe phenotypes, is characterized by childhood-onset progressive and ultimately severe encephalopathy with intractable epilepsy and hepatic failure. Childhood myocerebrohepatopathy spectrum (MCHS) presents between the first few months of life up to about age three years with developmental delay or dementia, lactic acidosis, and a myopathy with failure to thrive. Other findings can include liver failure, renal tubular acidosis, pancreatitis, cyclic vomiting, and hearing loss. Myoclonic epilepsy myopathy sensory ataxia (MEMSA) now describes the spectrum of disorders with epilepsy, myopathy, and ataxia without ophthalmoplegia. MEMSA now includes the disorders previously described as spinocerebellar ataxia with epilepsy (SCAE). The ataxia neuropathy spectrum (ANS) includes the phenotypes previously referred to as mitochondrial recessive ataxia syndrome (MIRAS) and sensory ataxia neuropathy dysarthria and ophthalmoplegia (SANDO). About 90% of persons in the ANS have ataxia and neuropathy as core features. Approximately two thirds develop seizures and almost one half develop ophthalmoplegia; clinical myopathy is rare. Autosomal recessive progressive external ophthalmoplegia (arPEO) is characterized by progressive weakness of the extraocular eye muscles resulting in ptosis and ophthalmoparesis (or paresis of the extraocular muscles) without associated systemic involvement; however, caution is advised because many individuals with apparently isolated arPEO at the onset develop other manifestations of POLG-related disorders over years or decades. Of note, in the ANS spectrum the neuropathy commonly precedes the onset of PEO by years to decades. Autosomal dominant progressive external ophthalmoplegia (adPEO) typically includes a generalized myopathy and often variable degrees of sensorineural hearing loss, axonal neuropathy, ataxia, depression, Parkinsonism, hypogonadism, and cataracts (in what has been called “chronic progressive external ophthalmoplegia plus,” or “CPEO+”).
Lissencephaly 1
MedGen UID:
375318
Concept ID:
C1843916
Disease or Syndrome
LIS1-associated lissencephaly includes Miller-Dieker syndrome (MDS), isolated lissencephaly sequence (ILS), and (rarely) subcortical band heterotopia (SBH). Lissencephaly and SBH are cortical malformations caused by deficient neuronal migration during embryogenesis. Lissencephaly refers to a "smooth brain" with absent gyri (agyria) or abnormally wide gyri (pachygyria). SBH refers to a band of heterotopic gray matter located just beneath the cortex and separated from it by a thin zone of normal white matter. MDS is characterized by lissencephaly, typical facial features, and severe neurologic abnormalities. ILS is characterized by lissencephaly and its direct sequelae: developmental delay, intellectual disability, and seizures.
Coenzyme Q10 deficiency, primary 1
MedGen UID:
334528
Concept ID:
C1843920
Disease or Syndrome
Primary CoQ10 deficiency is a rare, clinically heterogeneous autosomal recessive disorder caused by mutation in any of the genes encoding proteins directly involved in the synthesis of coenzyme Q (review by Quinzii and Hirano, 2011). Coenzyme Q10 (CoQ10), or ubiquinone, is a mobile lipophilic electron carrier critical for electron transfer by the mitochondrial inner membrane respiratory chain (Duncan et al., 2009). The disorder has been associated with 5 major phenotypes, but the molecular basis has not been determined in most patients with the disorder and there are no clear genotype/phenotype correlations. The phenotypes include an encephalomyopathic form with seizures and ataxia (Ogasahara et al., 1989); a multisystem infantile form with encephalopathy, cardiomyopathy and renal failure (Rotig et al., 2000); a predominantly cerebellar form with ataxia and cerebellar atrophy (Lamperti et al., 2003); Leigh syndrome with growth retardation (van Maldergem et al., 2002); and an isolated myopathic form (Lalani et al., 2005). The correct diagnosis is important because some patients may show a favorable response to CoQ10 treatment. Genetic Heterogeneity of Primary Coenzyme Q10 Deficiency See also COQ10D2 (614651), caused by mutation in the PDSS1 gene (607429) on chromosome 10p12; COQ10D3 (614652), caused by mutation in the PDSS2 gene (610564) on chromosome 6q21; COQ10D4 (612016), caused by mutation in the COQ8 gene (ADCK3; 606980) on chromosome 1q42; COQ10D5 (614654), caused by mutation in the COQ9 gene (612837) on chromosome 16q21; COQ10D6 (614650), caused by mutation in the COQ6 gene (614647) on chromosome 14q24; and COQ10D7 (616276), caused by mutation in the COQ4 gene (612898) on chromosome 9q34. Secondary CoQ10 deficiency has been reported in association with glutaric aciduria type IIC (MADD; 231680), caused by mutation in the ETFDH gene (231675) on chromosome 4q, and with ataxia-oculomotor apraxia syndrome-1 (AOA1; 208920), caused by mutation in the APTX gene (606350) on chromosome 9p13.
Hereditary hemihypotrophy hemiparesis hemiathetosis syndrome
MedGen UID:
336099
Concept ID:
C1844019
Disease or Syndrome
Catel Manzke syndrome
MedGen UID:
375536
Concept ID:
C1844887
Disease or Syndrome
Catel-Manzke syndrome is characterized by the Pierre Robin anomaly, which comprises cleft palate, glossoptosis, and micrognathia, and a unique form of bilateral hyperphalangy in which there is an accessory bone inserted between the second metacarpal and its corresponding proximal phalanx, resulting in radial deviation of the index finger (summary by Manzke et al., 2008).
Arthrogryposis multiplex congenita, distal, X-linked
MedGen UID:
337123
Concept ID:
C1844934
Disease or Syndrome
X-linked infantile spinal muscular atrophy (XL-SMA) is characterized by congenital hypotonia and areflexia and evidence of degeneration and loss of anterior horn cells (i.e., lower motor neurons) in the spinal cord and brain stem. Often congenital contractures and/or fractures are present. Intellect is normal. Life span is shortened because of progressive ventilatory insufficiency resulting from chest muscle involvement.
Spinocerebellar ataxia X-linked type 3
MedGen UID:
337124
Concept ID:
C1844936
Disease or Syndrome
A progressive disorder of the central nervous system characterized by ataxia, deafness, hypotonia, developmental delay, esotropia, and optic atrophy.
Pigmentary disorder, reticulate, with systemic manifestations
MedGen UID:
336844
Concept ID:
C1845050
Disease or Syndrome
ATR-X syndrome
MedGen UID:
337145
Concept ID:
C1845055
Disease or Syndrome
Alpha-thalassemia X-linked intellectual disability (ATRX) syndrome is characterized by distinctive craniofacial features, genital anomalies, severe developmental delays, hypotonia, intellectual disability, and mild-to-moderate anemia secondary to alpha-thalassemia. Craniofacial abnormalities include small head circumference, telecanthus or widely spaced eyes, short nose, tented vermilion of the upper lip, and thick or everted vermilion of the lower lip with coarsening of the facial features over time. Although all affected individuals have a normal 46,XY karyotype, genital anomalies range from hypospadias and undescended testicles to severe hypospadias and ambiguous genitalia, to normal-appearing female external genitalia. Global developmental delays are evident in infancy and some affected individuals never walk independently or develop significant speech.
Early infantile epileptic encephalopathy 8
MedGen UID:
375581
Concept ID:
C1845102
Disease or Syndrome
Hereditary hyperekplexia (HPX) is characterized by generalized stiffness immediately after birth that normalizes during the first years of life; excessive startle reflex (eye blinking and a flexor spasm of the trunk) to unexpected (particularly auditory) stimuli; and a short period of generalized stiffness following the startle response during which voluntary movements are impossible. Exaggerated head-retraction reflex (HRR) consisting of extension of the head followed by violent flexor spasms of limbs and neck muscles elicited by tapping the tip of the nose is observed in most children. Other findings include periodic limb movements in sleep (PLMS) and hypnagogic (occurring when falling asleep) myoclonus. Sudden infant death (SIDS) has been reported. Intellect is usually normal; mild intellectual disability may occur.
Mental retardation 91, X-linked
MedGen UID:
375592
Concept ID:
C1845142
Disease or Syndrome
Nephrogenic syndrome of inappropriate antidiuresis
MedGen UID:
336877
Concept ID:
C1845202
Disease or Syndrome
The syndrome of inappropriate antidiuretic hormone secretion (SIADH) is a common cause of hyponatremia. The syndrome manifests as an inability to excrete a free water load, with inappropriately concentrated urine and resultant hyponatremia, hypoosmolality, and natriuresis. SIADH occurs in a setting of normal blood volume, without evidence of renal disease or deficiency of thyroxine or cortisol. Although usually transient, SIADH may be chronic; it is often associated with drug use or a lesion in the central nervous system or lung. When the cardinal features of SIADH were defined by Bartter and Schwartz (1967), levels of AVP could not be measured. Subsequently, radioimmunoassays revealed that SIADH is usually associated with measurably elevated serum levels of AVP. Nephrogenic syndrome of inappropriate antidiuresis (NSIAD) is characterized by a clinical picture similar to SIADH, but is associated with undetectable levels of AVP (Feldman et al., 2005).
Heterotopia, periventricular, Ehlers-Danlos variant
MedGen UID:
375610
Concept ID:
C1845235
Disease or Syndrome
Periventricular heterotopia is a condition in which nerve cells (neurons) do not migrate properly during the early development of the fetal brain, from about the 6th week to the 24th week of pregnancy. Heterotopia means "out of place." In normal brain development, neurons form in the periventricular region, located around fluid-filled cavities (ventricles) near the center of the brain. The neurons then migrate outward to form the exterior of the brain (cerebral cortex) in six onion-like layers. In periventricular heterotopia, some neurons fail to migrate to their proper position and form clumps around the ventricles. Periventricular heterotopia usually becomes evident when seizures first appear, often during the teenage years. The nodules around the ventricles are then typically discovered when magnetic resonance imaging (MRI) studies are done. Affected individuals usually have normal intelligence, although some have mild intellectual disability. Difficulty with reading and spelling (dyslexia) has been reported in some people with periventricular heterotopia. Less commonly, individuals with periventricular heterotopia may have more severe brain malformations, small head size (microcephaly), developmental delays, recurrent infections, blood vessel abnormalities, or other problems. Periventricular heterotopia may also occur in association with other conditions such as Ehlers-Danlos syndrome, which results in extremely flexible joints, skin that stretches easily, and fragile blood vessels.
Mental retardation, syndromic, Claes-Jensen type, X-linked
MedGen UID:
335139
Concept ID:
C1845243
Disease or Syndrome
Autism, susceptibility to, X-linked 3
MedGen UID:
335161
Concept ID:
C1845336
Finding
Autism, the prototypic pervasive developmental disorder (PDD), is usually apparent by 3 years of age. It is characterized by a triad of limited or absent verbal communication, a lack of reciprocal social interaction or responsiveness, and restricted, stereotypic, and ritualized patterns of interests and behavior (Bailey et al., 1996; Risch et al., 1999). 'Autism spectrum disorder,' sometimes referred to as ASD, is a broader phenotype encompassing the less severe disorders Asperger syndrome (see ASPG1; 608638) and pervasive developmental disorder, not otherwise specified (PDD-NOS). 'Broad autism phenotype' includes individuals with some symptoms of autism, but who do not meet the full criteria for autism or other disorders. Mental retardation coexists in approximately two-thirds of individuals with ASD, except for Asperger syndrome, in which mental retardation is conspicuously absent (Jones et al., 2008). Genetic studies in autism often include family members with these less stringent diagnoses (Schellenberg et al., 2006). For a discussion of genetic heterogeneity of autism, see 209850.
Mental retardation X-linked with cerebellar hypoplasia and distinctive facial appearance
MedGen UID:
336920
Concept ID:
C1845366
Disease or Syndrome
Chromosome Xq28 deletion syndrome
MedGen UID:
336933
Concept ID:
C1845408
Disease or Syndrome
Deafness, dystonia, and cerebral hypomyelination is an X-linked recessive mental retardation syndrome characterized by almost no psychomotor development, dysmorphic facial features, sensorineural deafness, dystonia, pyramidal signs, and hypomyelination on brain imaging (summary by Cacciagli et al., 2013).
Cubitus valgus with mental retardation and unusual facies
MedGen UID:
336943
Concept ID:
C1845450
Disease or Syndrome
2-methyl-3-hydroxybutyric aciduria
MedGen UID:
336957
Concept ID:
C1845517
Disease or Syndrome
HSD10 deficiency is an X-linked dominant neurodegenerative disorder characterized by onset in late infancy or during childhood. The severity is highly variable, but some patients have slow loss of developmental skills, cardiomyopathy, retinal degeneration, and seizures; the features resemble a mitochondrial disorder. Unlike other organic acidurias, most patients do not develop severe metabolic crises in the neonatal period (summary by Rauschenberger et al., 2010).
Autism, susceptibility to, X-linked 2
MedGen UID:
336964
Concept ID:
C1845539
Finding
Autism, the prototypic pervasive developmental disorder (PDD), is usually apparent by 3 years of age. It is characterized by a triad of limited or absent verbal communication, a lack of reciprocal social interaction or responsiveness, and restricted, stereotypic, and ritualized patterns of interests and behavior (Bailey et al., 1996; Risch et al., 1999). 'Autism spectrum disorder,' sometimes referred to as ASD, is a broader phenotype encompassing the less severe disorders Asperger syndrome (see ASPG1; 608638) and pervasive developmental disorder, not otherwise specified (PDD-NOS). 'Broad autism phenotype' includes individuals with some symptoms of autism, but who do not meet the full criteria for autism or other disorders. Mental retardation coexists in approximately two-thirds of individuals with ASD, except for Asperger syndrome, in which mental retardation is conspicuously absent (Jones et al., 2008). Genetic studies in autism often include family members with these less stringent diagnoses (Schellenberg et al., 2006). For a discussion of genetic heterogeneity of autism, see 209850.
Autism, susceptibility to, X-linked 1
MedGen UID:
335205
Concept ID:
C1845540
Finding
Autism comprises a clinically heterogeneous group of disorders – collectively referred to as “autism spectrum disorders” (ASD) – that share common features of impaired social relationships, impaired language and communication, and repetitive behaviors or a narrow range of interests. For most children with autism, symptoms develop gradually, although approximately 30% have a "regressive" onset usually between ages 18 and 24 months. About 50%-70% of children with autism are identified as intellectually disabled by nonverbal IQ testing and approximately 25% develop seizures. Autism can be considered complex (i.e., presence of dysmorphic features and/or microcephaly) or essential (i.e., absence of physical abnormalities and microcephaly). About 25% of children who fit the diagnostic criteria for ASD at age two to three years subsequently begin to talk and communicate, and by age six to seven years blend to varying degrees into the regular school population. The remaining 75% have lifelong disability requiring intensive parental, school, and social support.
FG syndrome 4
MedGen UID:
336965
Concept ID:
C1845546
Disease or Syndrome
FG syndrome-4 is an X-linked recessive mental retardation syndrome characterized by congenital hypotonia, constipation, behavioral disturbances, and dysmorphic features (summary by Piluso et al., 2003). The name 'FG' derives from the first description of the disorder (FGS1; 305450) by Opitz and Kaveggia (1974), who named it 'FG syndrome' according to the Opitz system of using initials of patients' surnames. For a phenotypic description and a discussion of genetic heterogeneity of FG syndrome, see FGS1 (305450). FGS4 is typically associated with missense or hypomorphic mutations in the CASK gene. See also the more severe disorder MICPCH (300749), an allelic disorder caused by complete loss-of-function mutations in the CASK gene (Tarpey et al., 2009).
MENTAL RETARDATION, X-LINKED, WITH SHORT STATURE (disorder)
MedGen UID:
375754
Concept ID:
C1845845
Disease or Syndrome
Syndromic X-linked mental retardation, Cabezas type
MedGen UID:
337334
Concept ID:
C1845861
Disease or Syndrome
This form of syndromic X-linked mental retardation is characterized primarily by short stature, hypogonadism, and abnormal gait, with other more variable features such as speech delay, prominent lower lip, and tremor (Cabezas et al., 2000).
Creatine deficiency, X-linked
MedGen UID:
337451
Concept ID:
C1845862
Disease or Syndrome
The cerebral creatine deficiency syndromes (CCDS), inborn errors of creatine metabolism, include the two creatine biosynthesis disorders, guanidinoacetate methyltransferase (GAMT) deficiency and L-arginine:glycine amidinotransferase (AGAT or GATM) deficiency, and the creatine transporter (SLC6A8) deficiency. Intellectual disability and seizures are common to all three CCDS. The majority of individuals with GAMT deficiency have a behavior disorder that can include autistic behaviors and self-mutilation; a significant proportion have pyramidal/extrapyramidal findings. Onset is between ages three months and three years. Only seven individuals with AGAT deficiency have been reported. The phenotype of SLC6A8 deficiency in affected males ranges from mild intellectual disability and speech delay to severe intellectual disability, seizures, and behavior disorder; age at diagnosis ranges from two to 66 years. Females heterozygous for SLC6A8 deficiency may have learning and behavior problems.
Mental retardation, X-linked 72
MedGen UID:
375793
Concept ID:
C1846038
Disease or Syndrome
Adrenomyodystrophy
MedGen UID:
337494
Concept ID:
C1846044
Disease or Syndrome
Armfield X-linked mental retardation syndrome
MedGen UID:
375800
Concept ID:
C1846057
Disease or Syndrome
MECP2 duplication syndrome
MedGen UID:
337496
Concept ID:
C1846058
Mental or Behavioral Dysfunction
The MECP2 duplication syndrome is a severe neurodevelopmental disorder characterized by infantile hypotonia, delayed psychomotor development leading to severe intellectual disability, poor speech development, progressive spasticity, recurrent respiratory infections (in ~75% of affected individuals) and seizures (in ~50%). MECP2 duplication syndrome is 100% penetrant in males. Occasionally females have been described with a MECP2 duplication and related clinical findings, often associated with concomitant X-chromosomal abnormalities that prevent inactivation of the duplicated region. Generalized tonic-clonic seizures are most often observed; atonic seizures and absence seizures have also been described. One third of affected males are never able to walk independently. Almost 50% of affected males die before age 25 years, presumably from complications of recurrent infection and/or neurologic deterioration. In addition to the core features, autistic behaviors and gastrointestinal dysfunction have been observed in several affected boys. Although interfamilial phenotypic variability is observed, severity is usually consistent within families.
Mental retardation X-linked syndromic 11
MedGen UID:
335348
Concept ID:
C1846145
Disease or Syndrome
Spondyloepimetaphyseal dysplasia X-linked with mental deterioration
MedGen UID:
335350
Concept ID:
C1846148
Disease or Syndrome
Lissencephaly 2, X-linked
MedGen UID:
375832
Concept ID:
C1846171
Disease or Syndrome
X-linked lissencephaly-2 (LISX2) is a developmental disorder characterized by structural brain anomalies, early-onset intractable seizures, severe psychomotor retardation, and ambiguous genitalia. Males are severely affected and often die within the first days or months of life, whereas females may be unaffected or have a milder phenotype (Bonneau et al., 2002). LISX2 is part of a phenotypic spectrum of disorders caused by mutation in the ARX gene comprising a nearly continuous series of developmental disorders ranging from hydranencephaly and lissencephaly to Proud syndrome (300004) to infantile spasms without brain malformations (EIEE1; 308350) to syndromic (309510) and nonsyndromic (300419) mental retardation (Kato et al., 2004; Wallerstein et al., 2008). For a general phenotypic description and a discussion of genetic heterogeneity of lissencephaly, see LIS1 (607432).
Oculofaciocardiodental syndrome
MedGen UID:
337547
Concept ID:
C1846265
Disease or Syndrome
Lenz microphthalmia syndrome (LMS) is characterized by unilateral or bilateral microphthalmia and/or clinical anophthalmia with malformations of the ears, teeth, fingers, skeleton, and/or genitourinary system. Microphthalmia is often accompanied by microcornea and glaucoma. Coloboma is present in approximately 60% of microphthalmic eyes with severity ranging from isolated iris coloboma to coloboma of the ciliary body, choroid, and optic disk. Ears may be low set, anteverted, posteriorly rotated, simple, cup shaped, or abnormally modeled. Hearing loss has been observed. Dental findings include irregularly shaped, missing, or widely spaced teeth. Duplicated thumbs, syndactyly, clinodactyly, camptodactyly, and microcephaly are common, as are narrow/sloping shoulders, underdeveloped clavicles, kyphoscoliosis, exaggerated lumbar lordosis, long cylindric thorax, and webbed neck. Genitourinary anomalies include hypospadias, cryptorchidism, renal hypoplasia/aplasia, and hydroureter. Approximately 60% of affected males have mild-to-severe intellectual disability or developmental delay.
Mental retardation, epileptic seizures, hypogonadism and hypogenitalism, microcephaly, and obesity
MedGen UID:
375855
Concept ID:
C1846278
Disease or Syndrome
Lathosterolosis
MedGen UID:
375885
Concept ID:
C1846421
Disease or Syndrome
Gaze palsy, familial horizontal, with progressive scoliosis
MedGen UID:
339538
Concept ID:
C1846496
Disease or Syndrome
Horizontal gaze palsy with progressive scoliosis (HGPPS) is a disorder that affects vision and also causes an abnormal curvature of the spine (scoliosis). People with this condition are unable to move their eyes side-to-side (horizontally). As a result, affected individuals must turn their head instead of moving their eyes to track moving objects. Up-and-down (vertical) eye movements are typically normal. In people with HGPPS, an abnormal side-to-side curvature of the spine develops in infancy or childhood. It tends to be moderate to severe and worsens over time. Because the abnormal spine position can be painful and interfere with movement, it is often treated with surgery early in life.
Amish lethal microcephaly
MedGen UID:
375938
Concept ID:
C1846648
Disease or Syndrome
Amish lethal microcephaly is characterized by microcephaly and early death. The occipitofrontal circumference is typically six to 12 standard deviations below the mean; anterior and posterior fontanels are closed at birth and facial features are distorted. The average life span is between five and six months.
Spinocerebellar ataxia 17
MedGen UID:
337637
Concept ID:
C1846707
Disease or Syndrome
Spinocerebellar ataxia type 17 (SCA17) is characterized by ataxia, dementia, and involuntary movements, including chorea and dystonia. Psychiatric symptoms, pyramidal signs, and rigidity are common. The age of onset ranges from three to 55 years. Individuals with full-penetrance alleles develop neurologic and/or psychiatric symptoms by age 50 years. Ataxia and psychiatric abnormalities are frequently the initial findings, followed by involuntary movement, parkinsonism, dementia, and pyramidal signs. Brain MRI shows variable atrophy of the cerebrum, brain stem, and cerebellum. The clinical features correlate with the length of the polyglutamine expansion but are not absolutely predictive of the clinical course.
Polymicrogyria, bilateral frontoparietal
MedGen UID:
376107
Concept ID:
C1847352
Disease or Syndrome
Polymicrogyria is characterized by stable neurologic deficits, i.e., a "static encephalopathy." The mildest form, unilateral focal polymicrogyria, may have minimal neurologic manifestations. In more severe forms, focal, motor, sensory, visual, or cognitive problems may be present, depending on the brain region affected. In the most widespread form, bilateral generalized polymicrogyria, severe intellectual disability, cerebral palsy, and refractory epilepsy may be present.
Glucose transporter type 1 deficiency syndrome
MedGen UID:
337833
Concept ID:
C1847501
Disease or Syndrome
The phenotypic spectrum of glucose transporter type 1 deficiency syndrome (Glut1-DS) is now known to be a continuum that includes the classic phenotype as well as dystonia 9, dystonia 18, atypical childhood absence epilepsy, myoclonic astatic epilepsy, and paroxysmal non-epileptic findings such as intermittent ataxia, choreoathetosis, dystonia, and alternating hemiplegia. The classic phenotype is characterized by infantile-onset seizures, delayed neurologic development, acquired microcephaly, and complex movement disorders. Seizures begin before age two years in approximately 90% and later in approximately 10%. Several seizure types occur: generalized tonic or clonic, focal, myoclonic, atypical absence, atonic, and unclassified. The frequency, severity, and type of seizures vary among affected individuals and are not related to disease severity. Cognitive impairment, ranging from learning disabilities to severe intellectual disability, is typical. The complex movement disorder, characterized by ataxia, dystonia, and chorea, may occur in any combination and may be continuous, paroxysmal, or continuous with fluctuations in severity influenced by environmental factors such as fasting, fever, and intercurrent infection. Symptoms often improve substantially when a ketogenic diet is started.
Parkinson disease 9
MedGen UID:
338281
Concept ID:
C1847640
Disease or Syndrome
Parkinsonism refers to all clinical states characterized by tremor, muscle rigidity, slowed movement (bradykinesia) and often postural instability. Parkinson disease is the primary and most common form of parkinsonism. Psychiatric manifestations, which include depression and visual hallucinations, are common but not uniformly present. Dementia eventually occurs in at least 20% of cases. The most common sporadic form of Parkinson disease manifests around age 60; however, young-onset and even juvenile presentations are seen.
PHACE syndrome
MedGen UID:
376231
Concept ID:
C1847874
Disease or Syndrome
PHACE is an acronym for a neurocutaneous syndrome encompassing the following features: posterior fossa brain malformations, hemangiomas of the face (large or complex), arterial anomalies, cardiac anomalies, and eye abnormalities. The association is referred to as PHACES when ventral developmental defects, such as sternal clefting or supraumbilical raphe, are present (summary by Bracken et al., 2011).
Lissencephaly, X-linked
MedGen UID:
336286
Concept ID:
C1848199
Disease or Syndrome
DCX-related disorders include the neuronal migration disorders classic lissencephaly (formerly also known as lissencephaly type 1), usually in males; and subcortical band heterotopia (SBH, also called double cortex), primarily in females. Males with classic DCX-related lissencephaly typically have severe and global developmental delay, infantile-onset seizures (infantile spasms, West syndrome, focal and generalized seizures), and severe intellectual disability. In individuals with SBH, cognitive abilities range from normal to learning disabilities and/or severe intellectual disability. The majority of individuals with SBH present with focal or generalized seizures. Behavior problems may also be observed. In DCX-related lissencephaly and SBH the severity of the clinical manifestation correlates with the degree of the underlying brain malformation.
X-linked periventricular heterotopia
MedGen UID:
376309
Concept ID:
C1848213
Congenital Abnormality
X-linked periventricular heterotopia (PH), a neuronal migration disorder, is characterized by the presence of uncalcified nodules of neurons ectopically situated along the surface of the lateral ventricles. Affected individuals are predominantly heterozygous females; males show early lethality. Affected females present with seizures at an average age of 14-15 years; intelligence ranges from normal to borderline. The risk for stroke and other vascular/coagulation problems appears to be increased.
Intestinal pseudoobstruction neuronal chronic idiopathic X-linked
MedGen UID:
376311
Concept ID:
C1848221
Disease or Syndrome
Chronic idiopathic intestinal pseudoobstruction (CIIP) is caused by severe abnormality of gastrointestinal motility. Patients have recurrent symptoms and signs of intestinal obstruction without any mechanical lesion (Auricchio et al., 1996). Some primary forms of CIIP are caused by defects of enteric neuronal cells: see Hirschsprung disease (see, e.g., HSCR1; 142623) and autosomal recessive visceral neuropathy (243180) (Tanner et al., 1976).
Zunich neuroectodermal syndrome
MedGen UID:
341214
Concept ID:
C1848392
Disease or Syndrome
Zunich neuroectodermal syndrome is an extremely rare autosomal recessive multisystem disorder clinically characterized by colobomas, congenital heart defects, migratory ichthyosiform dermatosis, mental retardation, and ear anomalies (CHIME). Other clinical features include distinctive facial features, abnormal growth, genitourinary abnormalities, seizures, and feeding difficulties (summary by Ng et al., 2012).
Xylosidase deficiency
MedGen UID:
336338
Concept ID:
C1848407
Disease or Syndrome
Mental retardation Wolff type
MedGen UID:
336345
Concept ID:
C1848439
Disease or Syndrome
Pontocerebellar hypoplasia type 2A
MedGen UID:
376379
Concept ID:
C1848526
Disease or Syndrome
TSEN54-related pontocerebellar hypoplasia (PCH) includes three PCH types (PCH2, 4, and 5) that share characteristic neuroradiologic and neurologic findings. The three types (which differ mainly in life expectancy) were thought to be distinct entities before their molecular basis was known. Children with PCH2 usually succumb before age ten years, whereas those with PCH4 and 5 usually succumb as neonates. Children with PCH2 have generalized clonus, incoordination of sucking and swallowing, impaired motor and cognitive development with lack of voluntary motor development, central visual impairment, and an increased risk for malignant hyperthermia. Epilepsy is present in approximately 50%. Neonates with PCH4 often have seizures, multiple joint contractures (''arthrogryposis''), generalized clonus, and central respiratory impairment. PCH5, which resembles PCH4, has been described in one family.
Methylmalonic acidemia with homocystinuria cblD
MedGen UID:
341253
Concept ID:
C1848552
Disease or Syndrome
The clinical manifestations of disorders of intracellular cobalamin metabolism can be highly variable even within a single complementation group. The prototype and best understood is cblC; it is also the most common of these disorders. The age of initial presentation of cblC spans a wide range, including: Newborns, who can have intrauterine growth retardation (IUGR) and microcephaly; Infants, who can have poor feeding, failure to thrive, pallor, and neurologic signs, and occasionally hemolytic uremic syndrome (HUS) and/or seizures including infantile spasms; Toddlers, who can have failure to thrive, poor head growth, cytopenias (including megaloblastic anemia), global developmental delay, encephalopathy, and neurologic signs such as hypotonia and seizures; and Adolescents and adults, who can have neuropsychiatric symptoms, progressive cognitive decline, and/or subacute combined degeneration of the spinal cord.
Methylmalonic acidemia with homocystinuria
MedGen UID:
341256
Concept ID:
C1848561
Disease or Syndrome
The clinical manifestations of disorders of intracellular cobalamin metabolism can be highly variable even within a single complementation group. The prototype and best understood is cblC; it is also the most common of these disorders. The age of initial presentation of cblC spans a wide range, including: Newborns, who can have intrauterine growth retardation (IUGR) and microcephaly; Infants, who can have poor feeding, failure to thrive, pallor, and neurologic signs, and occasionally hemolytic uremic syndrome (HUS) and/or seizures including infantile spasms; Toddlers, who can have failure to thrive, poor head growth, cytopenias (including megaloblastic anemia), global developmental delay, encephalopathy, and neurologic signs such as hypotonia and seizures; and Adolescents and adults, who can have neuropsychiatric symptoms, progressive cognitive decline, and/or subacute combined degeneration of the spinal cord.
METHYLMALONIC ACIDURIA AND HOMOCYSTINURIA, cblF TYPE
MedGen UID:
336373
Concept ID:
C1848578
Disease or Syndrome
The clinical manifestations of disorders of intracellular cobalamin metabolism can be highly variable even within a single complementation group. The prototype and best understood is cblC; it is also the most common of these disorders. The age of initial presentation of cblC spans a wide range, including: Newborns, who can have intrauterine growth retardation (IUGR) and microcephaly; Infants, who can have poor feeding, failure to thrive, pallor, and neurologic signs, and occasionally hemolytic uremic syndrome (HUS) and/or seizures including infantile spasms; Toddlers, who can have failure to thrive, poor head growth, cytopenias (including megaloblastic anemia), global developmental delay, encephalopathy, and neurologic signs such as hypotonia and seizures; and Adolescents and adults, who can have neuropsychiatric symptoms, progressive cognitive decline, and/or subacute combined degeneration of the spinal cord.
Thyrocerebral-retinal syndrome
MedGen UID:
341311
Concept ID:
C1848813
Disease or Syndrome
Threoninemia
MedGen UID:
336439
Concept ID:
C1848861
Finding
Thoracic dysplasia-hydrocephalus syndrome
MedGen UID:
338562
Concept ID:
C1848864
Disease or Syndrome
Thalamic degeneration, symmetric infantile
MedGen UID:
376458
Concept ID:
C1848867
Disease or Syndrome
Cold-induced sweating syndrome 1
MedGen UID:
338577
Concept ID:
C1848947
Disease or Syndrome
Crisponi syndrome, the infantile presentation of cold-induced sweating syndrome (CISS), is characterized by dysmorphic features (distinctive facies, lower facial weakness, flexion deformity at the elbows, camptodactyly with fisted hands, misshapen feet, and overriding toes), poor suck reflex and severely impaired swallowing, temperature spikes not associated with infections, and increased risk for seizures and sudden death. During the first decade of life, children with CISS develop profuse sweating of the face, arms, and chest with ambient temperatures below 18º to 22º C and often with other stimuli including apprehension or ingestion of sweets. Affected individuals sweat very little in hot environments and may feel overheated. In the second decade, progressive thoracolumbar kyphoscoliosis requires intervention.
Schinzel-Giedion syndrome
MedGen UID:
341423
Concept ID:
C1849294
Disease or Syndrome
Schinzel-Giedion syndrome is a highly recognizable syndrome characterized by severe mental retardation, distinctive facial features, and multiple congenital malformations including skeletal abnormalities, genitourinary and renal malformations, and cardiac defects, as well as a higher-than-normal prevalence of tumors, notably neuroepithelial neoplasia (summary by Hoischen et al., 2010).
Knobloch syndrome 1
MedGen UID:
336594
Concept ID:
C1849409
Congenital Abnormality
Knobloch syndrome is an autosomal recessive developmental disorder primarily characterized by typical eye abnormalities, including high myopia, cataracts, dislocated lens, vitreoretinal degeneration, and retinal detachment, with occipital skull defects, which can range from occipital encephalocele to occult cutis aplasia (summary by Aldahmesh et al., 2011).
Retinal degeneration and epilepsy
MedGen UID:
341450
Concept ID:
C1849416
Disease or Syndrome
Pyridoxine-dependent epilepsy
MedGen UID:
340341
Concept ID:
C1849508
Disease or Syndrome
Pyridoxine-dependent epilepsy is characterized by intractable seizures that are not controlled with antiepileptic drugs but that respond both clinically and electrographically to large daily supplements of pyridoxine (vitamin B6). Multiple types of clinical seizures have been reported in individuals with pyridoxine-dependent epilepsy. Dramatic presentations consisting of prolonged seizures and recurrent episodes of status epilepticus are typical; recurrent self-limited events including partial seizures, generalized seizures, atonic seizures, myoclonic events, and infantile spasms also occur. Affected individuals may have electrographic seizures without clinical correlates. Infants with the classic neonatal presentation begin to experience seizures soon after birth. Atypical features include: late-onset seizures (age =3 years); seizures that initially respond to antiepileptic drugs and then become intractable; seizures during early life that do not respond to pyridoxine but that are then controlled with pyridoxine several months later; and prolonged seizure-free intervals (=5 1/2 months) that occur after pyridoxine discontinuation. Intellectual disability is common.
Pseudopapilledema, ocular hypotelorism, blepharophimosis, and hand anomalies
MedGen UID:
337882
Concept ID:
C1849661
Disease or Syndrome
Pseudoneonatal adrenoleukodystrophy
MedGen UID:
376636
Concept ID:
C1849678
Disease or Syndrome
Peroxisomal acyl-CoA oxidase deficiency is a disorder of peroxisomal fatty acid beta-oxidation. See also D-bifunctional protein deficiency (261515), caused by mutation in the HSD17B4 gene (601860) on chromosome 5q2. The clinical manifestations of these 2 deficiencies are similar to those of disorders of peroxisomal assembly, including Zellweger cerebrohepatorenal syndrome (see 214100) and neonatal adrenoleukodystrophy (see 601539) (Watkins et al., 1995).
Glycogen storage disease of heart, lethal congenital
MedGen UID:
337919
Concept ID:
C1849813
Disease or Syndrome
Phosphoenolpyruvate carboxykinase deficiency, cytosolic
MedGen UID:
342359
Concept ID:
C1849814
Disease or Syndrome
Leukodystrophy, hypomyelinating 3
MedGen UID:
342403
Concept ID:
C1850053
Disease or Syndrome
Autosomal recessive hypomyelinating leukodystrophy-3 (HLD3) is a severe neurologic disorder characterized by early infantile onset of global developmental delay, lack of development, lack of speech acquisition, and peripheral spasticity associated with decreased myelination in the central nervous system (summary by Feinstein et al., 2010). The disorder is phenotypically similar to X-linked Pelizaeus-Merzbacher disease (PMD; 312080), which is caused by mutation in the PLP1 gene (300401). For a general phenotypic description and a discussion of genetic heterogeneity of HLD, see 312080.
PEHO syndrome
MedGen UID:
342404
Concept ID:
C1850055
Disease or Syndrome
Osteopetrosis autosomal recessive 1
MedGen UID:
376708
Concept ID:
C1850127
Disease or Syndrome
Osteopetrosis (OPT) is a life-threatening disease caused by subnormal osteoclast function, with an incidence of 1 in 250,000 births. The disease usually manifests in the first few months of life with macrocephaly and frontal bossing, resulting in a characteristic facial appearance. Defective bone remodeling of the skull results in choanal stenosis with concomitant respiratory problems and feeding difficulties, which are the first clinical manifestation of disease. The expanding bone encroaches on neural foramina, leading to blindness, deafness, and facial palsy. Complete visual loss invariably occurs in all untreated patients, and hearing loss is estimated to affect 78% of patients with OPT. Tooth eruption defects and severe dental caries are common. Calcium feedback hemostasis is impaired, and children with OPT are at risk of developing hypocalcemia with attendant tetanic seizures and secondary hyperparathyroidism. The most severe complication of OPT, limiting survival, is bone marrow insufficiency. The abnormal expansion of cortical and trabecular bone physically limits the availability of medullary space for hematopoietic activity, leading to life-threatening cytopenia and secondary expansion of extramedullary hematopoiesis at sites such as the liver and spleen (summary by Aker et al., 2012). Genetic Heterogeneity of Autosomal Recessive Osteopetrosis Other forms of autosomal recessive infantile malignant osteopetrosis include OPTB4 (611490), which is caused by mutation in the CLCN7 gene (602727) on chromosome 16p13, and OPTB5 (259720), which is caused by mutation in the OSTM1 gene (607649) on chromosome 6q21. A milder, osteoclast-poor form of autosomal recessive osteopetrosis (OPTB2; 259710) is caused by mutation in the TNFSF11 gene (602642) on chromosome 13q14, an intermediate form (OPTB6; 611497) is caused by mutation in the PLEKHM1 gene (611466) on chromosome 17q21, and a severe osteoclast-poor form associated with hypogammaglobulinemia (OPTB7; 612301) is caused by mutation in the TNFRSF11A gene (603499) on chromosome 18q22.1. Another form of autosomal recessive osteopetrosis (OPTB8; 615085) is caused by mutation in the SNX10 gene (614780) on chromosome 7p15. A form of autosomal recessive osteopetrosis associated with renal tubular acidosis (OPTB3; 259730) is caused by mutation in the gene encoding carbonic anhydrase II (611492) on chromosome 8q22. Autosomal dominant forms of osteopetrosis are more benign (see OPTA1, 607634). Osteosclerosis also occurs in pycnodysostosis (265800), in van Buchem disease (239100), and in sclerosteosis (269500).
Osteodysplasia, familial, Anderson type
MedGen UID:
337990
Concept ID:
C1850186
Disease or Syndrome
Oliver syndrome
MedGen UID:
342472
Concept ID:
C1850320
Disease or Syndrome
Oculocerebral hypopigmentation syndrome of preus
MedGen UID:
342477
Concept ID:
C1850340
Disease or Syndrome
Ceroid lipofuscinosis neuronal 5
MedGen UID:
376792
Concept ID:
C1850442
Disease or Syndrome
The neuronal ceroid-lipofuscinoses (NCLs) are a group of inherited, neurodegenerative, lysosomal storage disorders characterized by progressive intellectual and motor deterioration, seizures, and early death. Visual gvhmloss is a feature of most forms. Clinical phenotypes have been characterized traditionally according to the age of onset and order of appearance of clinical features into infantile, late-infantile, juvenile, adult, and Northern epilepsy (also known as progressive epilepsy with mental retardation [EPMR]). There is however genetic and allelic heterogeneity; a proposed new nomenclature and classification system has been developed to take into account both the responsible gene and the age at disease onset; for example, CLN1 disease, infantile onset and CLN1 disease, juvenile onset are both caused by mutations in PPT1 but with differing age of onset. The most prevalent NCLs are CLN3 disease, classic juvenile and CLN2 disease, classic late infantile (although prevalence varies by ethnicity and country of family origin): CLN2 disease, classic late infantile. The first symptoms typically appear between age two and four years, usually starting with epilepsy, followed by regression of developmental milestones, myoclonic ataxia, and pyramidal signs. Visual impairment typically appears at age four to six years and rapidly progresses to light /dark awareness only. Life expectancy ranges from age six years to early teenage. CLN3 disease, classic juvenile. Onset is usually between ages four and ten years. Rapidly progressing visual loss resulting in severe visual impairment within one to two years is often the first clinical sign. Epilepsy with generalized tonic-clonic seizures and/or complex-partial seizures typically appears around age ten years. Life expectancy ranges from the late teens to the 30s. Other forms of NCL may present with behavior changes, epilepsy, visual impairment, or slowing of developmental progress and then loss of skills. The course may be extremely variable. Some genotype-phenotype information is available.
Ceroid lipofuscinosis neuronal 1
MedGen UID:
340540
Concept ID:
C1850451
Disease or Syndrome
The neuronal ceroid-lipofuscinoses (NCLs) are a group of inherited, neurodegenerative, lysosomal storage disorders characterized by progressive intellectual and motor deterioration, seizures, and early death. Visual gvhmloss is a feature of most forms. Clinical phenotypes have been characterized traditionally according to the age of onset and order of appearance of clinical features into infantile, late-infantile, juvenile, adult, and Northern epilepsy (also known as progressive epilepsy with mental retardation [EPMR]). There is however genetic and allelic heterogeneity; a proposed new nomenclature and classification system has been developed to take into account both the responsible gene and the age at disease onset; for example, CLN1 disease, infantile onset and CLN1 disease, juvenile onset are both caused by mutations in PPT1 but with differing age of onset. The most prevalent NCLs are CLN3 disease, classic juvenile and CLN2 disease, classic late infantile (although prevalence varies by ethnicity and country of family origin): CLN2 disease, classic late infantile. The first symptoms typically appear between age two and four years, usually starting with epilepsy, followed by regression of developmental milestones, myoclonic ataxia, and pyramidal signs. Visual impairment typically appears at age four to six years and rapidly progresses to light /dark awareness only. Life expectancy ranges from age six years to early teenage. CLN3 disease, classic juvenile. Onset is usually between ages four and ten years. Rapidly progressing visual loss resulting in severe visual impairment within one to two years is often the first clinical sign. Epilepsy with generalized tonic-clonic seizures and/or complex-partial seizures typically appears around age ten years. Life expectancy ranges from the late teens to the 30s. Other forms of NCL may present with behavior changes, epilepsy, visual impairment, or slowing of developmental progress and then loss of skills. The course may be extremely variable. Some genotype-phenotype information is available.
Elejalde disease
MedGen UID:
342508
Concept ID:
C1850466
Disease or Syndrome
Nakajo syndrome
MedGen UID:
376827
Concept ID:
C1850568
Disease or Syndrome
This autosomal recessive systemic autoinflammatory disorder is characterized by early childhood onset of annular erythematous plaques on the face and extremities with subsequent development of partial lipodystrophy and laboratory evidence of immune dysregulation. More variable features include recurrent fever, severe joint contractures, muscle weakness and atrophy, hepatosplenomegaly, basal ganglia calcifications, and microcytic anemia (summary by Agarwal et al., 2010; Kitamura et al., 2011; Arima et al., 2011). This disorder encompasses Nakajo-Nishimura syndrome (NKJO); joint contractures, muscular atrophy, microcytic anemia, and panniculitis-induced lipodystrophy (JMP syndrome); and chronic atypical neutrophilic dermatosis with lipodystrophy and elevated temperature syndrome (CANDLE). Among Japanese patients, this disorder is best described as Nakajo-Nishimura syndrome, since both Nakajo (1939) and Nishimura et al. (1950) contributed to the original phenotypic descriptions.
Gingival fibromatosis with hypertrichosis
MedGen UID:
342675
Concept ID:
C1851120
Disease or Syndrome
Extreme hirsutism with gingival fibromatosis follows a dominant pattern of inheritance (Weski, 1920; Garn and Hatch, 1950). There is no necessary relationship between the age of development of the gingival changes and the hypertrichosis. The latter may be present at birth but often appears at puberty (Anderson et al., 1969). For a discussion of genetic heterogeneity of congenital generalized hypertrichosis, see HTC1 (145701).
Epilepsy, benign occipital
MedGen UID:
377052
Concept ID:
C1851549
Disease or Syndrome
Mitochondrial complex III deficiency
MedGen UID:
377658
Concept ID:
C1852372
Disease or Syndrome
Autosomal recessive mitochondrial complex III deficiency is a severe multisystem disorder with onset at birth of lactic acidosis, hypotonia, hypoglycemia, failure to thrive, encephalopathy, and delayed psychomotor development. Visceral involvement, including hepatopathy and renal tubulopathy, may also occur. Many patients die in early childhood, but some may show longer survival (de Lonlay et al., 2001; De Meirleir et al., 2003). Genetic Heterogeneity of Mitochondrial Complex III Deficiency Mitochondrial complex III deficiency can be caused by mutation in several different nuclear-encoded genes. See MC3DN2 (615157), caused by mutation in the TTC19 gene (613814) on chromosome 17p12; MC3DN3 (615158), caused by mutation in the UQCRB gene (191330) on chromosome 8q; MC3DN4 (615159), caused by mutation in the UQCRQ gene (612080) on chromosome 5q31; MC3DN5 (615160), caused by mutation in the UQCRC2 gene (191329) on chromosome 16p12; MC3DN6 (615453), caused by mutation in the CYC1 gene (123980) on chromosome 8q24; MC3DN7 (615824), caused by mutation in the UQCC2 gene (614461) on chromosome 6p21; MC3DN8 (615838), caused by mutation in the LYRM7 gene (615831) on chromosome 5q23; and MC3DN9 (616111), caused by mutation in the UQCC3 gene (616097) on chromosome 11q12. See also MTYCB (516020) for a discussion of a milder phenotype associated with isolated mitochondrial complex III deficiency and mutations in a mitochondrial-encoded gene.
Copper deficiency, familial benign
MedGen UID:
338958
Concept ID:
C1852576
Disease or Syndrome
Renal coloboma syndrome
MedGen UID:
339002
Concept ID:
C1852759
Disease or Syndrome
Renal coloboma (papillorenal syndrome) is an autosomal dominant condition characterized by renal hypodysplasia and abnormalities of the optic nerve. Abnormal renal structure or function is noted in 92% of affected individuals; ophthalmologic abnormalities are noted in 77% of affected individuals who have pathogenic variants in PAX2. Renal abnormalities can be clinically silent in rare individuals. In most individuals, clinically significant renal insufficiency/renal failure is reported. End-stage renal disease requiring renal transplant is not uncommon. Ophthalmologic abnormalities are typically described as optic nerve coloboma or dysplasia. Iris colobomas have not been reported in any individual with a PAX2 pathogenic variant. Ophthalmologic abnormalities may significantly impair vision in some individuals, while others have subtle changes only noted after detailed ophthalmologic examination. Additional clinical findings include hearing loss, which is noted in 7% of individuals with identified pathogenic variants in PAX2.
Severe congenital neutropenia
MedGen UID:
343974
Concept ID:
C1853118
Disease or Syndrome
Severe congenital neutropenia is a condition that causes affected individuals to be prone to recurrent infections. People with this condition have a shortage (deficiency) of neutrophils, a type of white blood cell that plays a role in inflammation and in fighting infection. The deficiency of neutrophils, called neutropenia, is apparent at birth or soon afterward. It leads to recurrent infections beginning in infancy, including infections of the sinuses, lungs, and liver. Affected individuals can also develop fevers and inflammation of the gums (gingivitis) and skin. Approximately 40 percent of affected people have decreased bone density (osteopenia) and may develop osteoporosis, a condition that makes bones progressively more brittle and prone to fracture. In people with severe congenital neutropenia, these bone disorders can begin at any time from infancy through adulthood. Approximately 20 percent of people with severe congenital neutropenia develop cancer of the blood-forming tissue (leukemia) or a disease of the blood and bone marrow (myelodysplastic syndrome) during adolescence. Some people with severe congenital neutropenia have additional health problems such as seizures, developmental delay, or heart and genital abnormalities.
Glycosylphosphatidylinositol deficiency
MedGen UID:
342819
Concept ID:
C1853205
Disease or Syndrome
Pachygyria, frontotemporal
MedGen UID:
343995
Concept ID:
C1853215
Disease or Syndrome
22q13.3 deletion syndrome
MedGen UID:
339994
Concept ID:
C1853490
Disease or Syndrome
Phelan-McDermid syndrome (22q13.3 deletion syndrome) is characterized by neonatal hypotonia, global developmental delay, absent to severely delayed speech, and normal to accelerated growth. Most individuals have moderate to profound intellectual disability. Other features include large fleshy hands, dysplastic toenails, and decreased perspiration that results in a tendency to overheat. Behavior characteristics include mouthing or chewing non-food items, decreased perception of pain, and autistic-like affect.
Genitopatellar syndrome
MedGen UID:
381208
Concept ID:
C1853566
Disease or Syndrome
Genitopatellar syndrome is a rare disorder consisting of microcephaly, severe psychomotor retardation, and characteristic coarse facial features, including broad nose and small or retracted chin, associated with congenital flexion contractures of the lower extremities, abnormal or missing patellae, and urogenital anomalies (summary by Penttinen et al., 2009). The SBBYS variant of Ohdo syndrome (603736) is an allelic disorder with overlapping features.
Fryns-Aftimos syndrome
MedGen UID:
340016
Concept ID:
C1853623
Disease or Syndrome
Congenital disorder of glycosylation type 2B
MedGen UID:
342954
Concept ID:
C1853736
Disease or Syndrome
Congenital disorders of N-linked glycosylation (abbreviated here as CDG-N-linked), are a group of disorders of N-linked oligosaccharides caused by deficiency in 42 different enzymes in the N-linked synthetic pathway. Most commonly, the disorders begin in infancy; manifestations range from severe developmental delay and hypotonia with multiple organ system involvement to hypoglycemia and protein-losing enteropathy with normal development. However, most types have been described in only a few individuals, and thus understanding of the phenotypes is limited. In PMM2-CDG (CDG-Ia), the most common type reported, the clinical presentation and course are highly variable, ranging from death in infancy to mild involvement in adults.
Epilepsy, nocturnal frontal lobe, type 3
MedGen UID:
344263
Concept ID:
C1854335
Disease or Syndrome
Autosomal dominant nocturnal frontal lobe epilepsy (ADNFLE) is characterized by clusters of nocturnal motor seizures, which are often stereotyped and brief (5 seconds to 5 minutes). They vary from simple arousals from sleep to dramatic, often bizarre, hyperkinetic events with tonic or dystonic features. Affected individuals may experience aura. Retained awareness during seizures is common. A minority of individuals experience daytime seizures. Onset ranges from infancy to adulthood. About 80% of individuals develop ADNFLE in the first two decades of life; mean age of onset is ten years. Clinical neurologic examination is normal and intellect is usually preserved, but reduced intellect, psychiatric comorbidity, or cognitive deficits may occur. Within a family, the manifestations of the disorder may vary considerably. ADNFLE is lifelong but not progressive. As an individual reaches middle age, attacks may become milder and less frequent.
Growth deficiency and mental retardation with facial dysmorphism
MedGen UID:
340266
Concept ID:
C1854630
Disease or Syndrome
Muscular dystrophy, adult-onset, with leukoencephalopathy
MedGen UID:
340269
Concept ID:
C1854646
Disease or Syndrome
Molybdenum cofactor deficiency, complementation group A
MedGen UID:
381530
Concept ID:
C1854988
Disease or Syndrome
Molybdenum cofactor deficiency is a rare condition characterized by brain dysfunction (encephalopathy) that worsens over time. Babies with this condition appear normal at birth, but within a week they have difficulty feeding and develop seizures that do not improve with treatment (intractable seizures). Brain abnormalities, including deterioration (atrophy) of brain tissue, lead to severe developmental delay; affected individuals usually do not learn to sit unassisted or to speak. A small percentage of affected individuals have an exaggerated startle reaction (hyperekplexia) to unexpected stimuli such as loud noises. Other features of molybdenum cofactor deficiency can include a small head size (microcephaly) and facial features that are described as "coarse." Tests reveal that affected individuals have high levels of chemicals called sulfite, S-sulfocysteine, xanthine, and hypoxanthine in the urine and low levels of a chemical called uric acid in the blood. Because of the serious health problems caused by molybdenum cofactor deficiency, affected individuals usually do not survive past early childhood.
Mitochondrial complex II deficiency
MedGen UID:
344401
Concept ID:
C1855008
Disease or Syndrome
Complex II, also known as succinate dehydrogenase (EC 1.3.5.1), is part of the mitochondrial respiratory chain. Deficiency of complex II is characterized by highly variable phenotypic expression.
Mitochondrial myopathy with lactic acidosis
MedGen UID:
343245
Concept ID:
C1855033
Disease or Syndrome
Microcephaly with chorioretinopathy, autosomal recessive
MedGen UID:
343252
Concept ID:
C1855056
Disease or Syndrome
Microcephaly and chorioretinopathy is an autosomal recessive developmental disorder characterized by delayed psychomotor development and visual impairment, often accompanied by short stature (summary by Martin et al., 2014). Genetic Heterogeneity of Microcephaly and Chorioretinopathy See also MCCRP2 (616171), caused by mutation in the PLK4 gene (605031) on chromosome 4q27, and MCCRP3 (616335), caused by mutation in the TUBGCP4 gene (609610) on chromosome 15q15. An autosomal dominant form of microcephaly with or without chorioretinopathy, lymphedema, or mental retardation is caused by heterozygous mutation in the KIF11 gene (148760) on chromosome 10q23.33. See also Mirhosseini-Holmes-Walton syndrome (autosomal recessive pigmentary retinopathy and mental retardation; 268050), which has been mapped to chromosome 8q21.3-q22.1
Winship Viljoen Leary syndrome
MedGen UID:
381554
Concept ID:
C1855080
Disease or Syndrome
Severe microcephaly and self-limiting dilated cardiomyopathy (which improved later in childhood) associated with delayed development and mildly dysmorphic facies..
Primary autosomal recessive microcephaly 1
MedGen UID:
344415
Concept ID:
C1855081
Disease or Syndrome
Primary autosomal recessive microcephalies (MCPH) and Seckel syndrome (SCKS) spectrum disorders are characterized by microcephaly and the absence of visceral malformations. Although MCHP and SCKS were previously distinguished by height (maximum height in SCKS was equivalent to the minimum height in MCPH), stature is no longer a discriminating feature, leading to the conclusion that these phenotypes constitute a spectrum rather than distinct entities. Microcephaly is characterized by: Onset during the second trimester of gestation; Occipito-frontal head circumference (OFC) at birth equal to or less than -2 SD below the mean for sex, age, and ethnicity; Slower than average increase in OFC after birth. Variable findings in the MCPH-SCKS spectrum disorders include: Brain structure (which is normal in the majority); Degree of cognitive impairment (usually mild to moderate without significant motor delay in the majority of persons with MCPH and more severe in those with SCKS and MCPH with brain malformations); Degree of short stature; Craniosynostosis (which may be secondary to poor brain growth).
Methylmalonic aciduria cblA type
MedGen UID:
344422
Concept ID:
C1855109
Disease or Syndrome
Isolated methylmalonic acidemia/aciduria is caused by complete or partial deficiency of the enzyme methylmalonyl-CoA mutase (mut(0) enzymatic subtype or mut(–) enzymatic subtype, respectively), a defect in the transport or synthesis of its cofactor, adenosyl-cobalamin (cblA, cblB, or cblD variant 2 type), or deficiency of the enzyme methylmalonyl-CoA epimerase. Onset of the manifestations of isolated methylmalonic acidemia/aciduria ranges from the neonatal period to adulthood. All phenotypes demonstrate periods of relative health and intermittent metabolic decompensation, usually associated with intercurrent infections and stress. In the neonatal period the disease can present with lethargy, vomiting, hypotonia, hypothermia, respiratory distress, severe ketoacidosis, hyperammonemia, neutropenia, and thrombocytopenia and can result in death. In the infantile/non-B12-responsive phenotype, the most common form, infants are normal at birth but develop lethargy, vomiting, dehydration, hepatomegaly, hypotonia, and encephalopathy. An intermediate B12-responsive phenotype can occasionally present in neonates, but usually presents in the first months or years of life; affected children exhibit anorexia, failure to thrive, hypotonia, and developmental delay, and sometimes have protein aversion and/or vomiting and lethargy after protein intake. Atypical and "benign"/adult methylmalonic acidemia are associated with increased, albeit mild, urinary excretion of methylmalonate; however, it is uncertain if some of these individuals will develop symptoms. Major secondary complications of methylmalonic acidemia include developmental delay (variable); tubulointerstitial nephritis with progressive renal failure; “metabolic stroke” (acute and chronic basal ganglia involvement); disabling movement disorder with choreoathetosis, dystonia, and para/quadriparesis; pancreatitis; growth failure; functional immune impairment; and optic nerve atrophy.
Methylmalonic aciduria due to methylmalonyl-CoA mutase deficiency
MedGen UID:
344424
Concept ID:
C1855114
Disease or Syndrome
Isolated methylmalonic acidemia/aciduria is caused by complete or partial deficiency of the enzyme methylmalonyl-CoA mutase (mut(0) enzymatic subtype or mut(–) enzymatic subtype, respectively), a defect in the transport or synthesis of its cofactor, adenosyl-cobalamin (cblA, cblB, or cblD variant 2 type), or deficiency of the enzyme methylmalonyl-CoA epimerase. Onset of the manifestations of isolated methylmalonic acidemia/aciduria ranges from the neonatal period to adulthood. All phenotypes demonstrate periods of relative health and intermittent metabolic decompensation, usually associated with intercurrent infections and stress. In the neonatal period the disease can present with lethargy, vomiting, hypotonia, hypothermia, respiratory distress, severe ketoacidosis, hyperammonemia, neutropenia, and thrombocytopenia and can result in death. In the infantile/non-B12-responsive phenotype, the most common form, infants are normal at birth but develop lethargy, vomiting, dehydration, hepatomegaly, hypotonia, and encephalopathy. An intermediate B12-responsive phenotype can occasionally present in neonates, but usually presents in the first months or years of life; affected children exhibit anorexia, failure to thrive, hypotonia, and developmental delay, and sometimes have protein aversion and/or vomiting and lethargy after protein intake. Atypical and "benign"/adult methylmalonic acidemia are associated with increased, albeit mild, urinary excretion of methylmalonate; however, it is uncertain if some of these individuals will develop symptoms. Major secondary complications of methylmalonic acidemia include developmental delay (variable); tubulointerstitial nephritis with progressive renal failure; “metabolic stroke” (acute and chronic basal ganglia involvement); disabling movement disorder with choreoathetosis, dystonia, and para/quadriparesis; pancreatitis; growth failure; functional immune impairment; and optic nerve atrophy.
3-methylglutaconic aciduria type IV
MedGen UID:
344425
Concept ID:
C1855126
Disease or Syndrome
The category of 3-methylglutaconic aciduria type IV (MGCA4) represents a heterogeneous unclassified group of patients who share mild or intermittent urinary excretion of 3-methylglutaconic acid. MGCA excretion is a nonspecific finding observed in many other disorders caused by defects in mitochondrial energy metabolism (Gunay-Aygun, 2005). For a general phenotypic description and a discussion of genetic heterogeneity of 3-methylglutaconic aciduria, see MGCA1 (250950)
METHYLCOBALAMIN DEFICIENCY, cblG TYPE
MedGen UID:
344426
Concept ID:
C1855128
Disease or Syndrome
The clinical manifestations of disorders of intracellular cobalamin metabolism can be highly variable even within a single complementation group. The prototype and best understood is cblC; it is also the most common of these disorders. The age of initial presentation of cblC spans a wide range, including: Newborns, who can have intrauterine growth retardation (IUGR) and microcephaly; Infants, who can have poor feeding, failure to thrive, pallor, and neurologic signs, and occasionally hemolytic uremic syndrome (HUS) and/or seizures including infantile spasms; Toddlers, who can have failure to thrive, poor head growth, cytopenias (including megaloblastic anemia), global developmental delay, encephalopathy, and neurologic signs such as hypotonia and seizures; and Adolescents and adults, who can have neuropsychiatric symptoms, progressive cognitive decline, and/or subacute combined degeneration of the spinal cord.
Mental retardation syndrome, Belgian type
MedGen UID:
343317
Concept ID:
C1855303
Disease or Syndrome
Megalencephaly with dysmyelination
MedGen UID:
344470
Concept ID:
C1855309
Disease or Syndrome
Mastocytosis cutaneous with short stature conductive hearing loss and microtia
MedGen UID:
383661
Concept ID:
C1855345
Disease or Syndrome
Pyruvate dehydrogenase E3-binding protein deficiency
MedGen UID:
343383
Concept ID:
C1855553
Disease or Syndrome
Pyruvate dehydrogenase deficiency is characterized by the buildup of a chemical called lactic acid in the body and a variety of neurological problems. Signs and symptoms of this condition usually first appear shortly after birth, and they can vary widely among affected individuals. The most common feature is a potentially life-threatening buildup of lactic acid (lactic acidosis), which can cause nausea, vomiting, severe breathing problems, and an abnormal heartbeat. People with pyruvate dehydrogenase deficiency usually have neurological problems as well. Most have delayed development of mental abilities and motor skills such as sitting and walking. Other neurological problems can include intellectual disability, seizures, weak muscle tone (hypotonia), poor coordination, and difficulty walking. Some affected individuals have abnormal brain structures, such as underdevelopment of the tissue connecting the left and right halves of the brain (corpus callosum), wasting away (atrophy) of the exterior part of the brain known as the cerebral cortex, or patches of damaged tissue (lesions) on some parts of the brain. Because of the severe health effects, many individuals with pyruvate dehydrogenase deficiency do not survive past childhood, although some may live into adolescence or adulthood.
Keutel syndrome
MedGen UID:
383722
Concept ID:
C1855607
Disease or Syndrome
Keutal syndrome is an autosomal recessive disorder characterized by multiple peripheral pulmonary stenoses, brachytelephalangy, inner ear deafness, and abnormal cartilage ossification or calcification (summary by Khosroshahi et al., 2014).
Ketoadipicaciduria
MedGen UID:
340920
Concept ID:
C1855626
Disease or Syndrome
Kenny-Caffey syndrome type 1
MedGen UID:
340923
Concept ID:
C1855648
Disease or Syndrome
Baraitser-Winter syndrome 1
MedGen UID:
340943
Concept ID:
C1855722
Disease or Syndrome
BRWS is a rare developmental phenotype characterized by the combination of hypertelorism, broad nose with large tip and prominent root, congenital nonmyopathic ptosis, ridged metopic suture, arched eyebrows, iris or retinal coloboma, sensorineural deafness, shoulder girdle muscle bulk and progressive joint stiffness, and pachygyria with anteroposterior severity gradient, rarely lissencephaly or neuronal heterotopia. Cleft lip and palate, hallux duplex, congenital heart defects and renal tract anomalies are seen in some cases. Microcephaly may develop with time. Early muscular involvement, occasionally with congenital arthrogryposis, may be present. Intellectual disability and epilepsy are variable in severity and largely correlate with central nervous system anomalies (summary by Verloes et al., 2015). Di Donato et al. (2014) and Verloes et al. (2015) suggested that BRWS, Fryns-Aftimos syndrome, and cerebrofrontofacial syndrome represent the same clinical entity. Genetic Heterogeneity of Baraitser-Winter Syndrome Baraitser-Winter syndrome-2 (BRWS2; 614583) is caused by heterozygous mutation in the ACTG1 gene (102560) on chromosome 17q25.
Absent corpus callosum cataract immunodeficiency
MedGen UID:
340962
Concept ID:
C1855772
Disease or Syndrome
Vici syndrome is a rare congenital multisystem disorder characterized by agenesis of the corpus callosum, cataracts, pigmentary defects, progressive cardiomyopathy, and variable immunodeficiency. Affected individuals also have profound psychomotor retardation and hypotonia due to a myopathy (summary by Finocchi et al., 2012).
Hypoparathyroidism retardation dysmorphism syndrome
MedGen UID:
340984
Concept ID:
C1855840
Disease or Syndrome
Bartter syndrome antenatal type 2
MedGen UID:
343428
Concept ID:
C1855849
Disease or Syndrome
Bartter syndrome is a group of very similar kidney disorders that cause an imbalance of potassium, sodium, chloride, and related molecules in the body. In some cases, Bartter syndrome becomes apparent before birth. The disorder can cause polyhydramnios, which is an increased volume of fluid surrounding the fetus (amniotic fluid). Polyhydramnios increases the risk of premature birth. Beginning in infancy, affected individuals often fail to grow and gain weight at the expected rate (failure to thrive). They lose excess amounts of salt (sodium chloride) in their urine, which leads to dehydration, constipation, and increased urine production (polyuria). In addition, large amounts of calcium are lost through the urine (hypercalciuria), which can cause weakening of the bones (osteopenia). Some of the calcium is deposited in the kidneys as they are concentrating urine, leading to hardening of the kidney tissue (nephrocalcinosis). Bartter syndrome is also characterized by low levels of potassium in the blood (hypokalemia), which can result in muscle weakness, cramping, and fatigue. Rarely, affected children develop hearing loss caused by abnormalities in the inner ear (sensorineural deafness). Two major forms of Bartter syndrome are distinguished by their age of onset and severity. One form begins before birth (antenatal) and is often life-threatening. The other form, often called the classical form, begins in early childhood and tends to be less severe. Once the genetic causes of Bartter syndrome were identified, researchers also split the disorder into different types based on the genes involved. Types I, II, and IV have the features of antenatal Bartter syndrome. Because type IV is also associated with hearing loss, it is sometimes called antenatal Bartter syndrome with sensorineural deafness. Type III usually has the features of classical Bartter syndrome.
Hypoglycemia, neonatal, simulating foetopathia diabetica
MedGen UID:
343429
Concept ID:
C1855860
Disease or Syndrome
Hypoglycemia with deficiency of glycogen synthetase in the liver
MedGen UID:
343430
Concept ID:
C1855861
Disease or Syndrome
Glycogen storage disease type 0 (also known as GSD 0) is a condition caused by the body's inability to form a complex sugar called glycogen, which is a major source of stored energy in the body. GSD 0 has two types: in muscle GSD 0, glycogen formation in the muscles is impaired, and in liver GSD 0, glycogen formation in the liver is impaired. The signs and symptoms of muscle GSD 0 typically begin in early childhood. Affected individuals often experience muscle pain and weakness or episodes of fainting (syncope) following moderate physical activity, such as walking up stairs. The loss of consciousness that occurs with fainting typically lasts up to several hours. Some individuals with muscle GSD 0 have a disruption of the heart's normal rhythm (arrhythmia) known as long QT syndrome. In all affected individuals, muscle GSD 0 impairs the heart's ability to effectively pump blood and increases the risk of cardiac arrest and sudden death, particularly after physical activity. Sudden death from cardiac arrest can occur in childhood or adolescence in people with muscle GSD 0. Individuals with liver GSD 0 usually show signs and symptoms of the disorder in infancy. People with this disorder develop low blood sugar (hypoglycemia) after going long periods of time without food (fasting). Signs of hypoglycemia become apparent when affected infants begin sleeping through the night and stop late-night feedings; these infants exhibit extreme tiredness (lethargy), pale skin (pallor), and nausea. During episodes of fasting, ketone levels in the blood may increase (ketosis). Ketones are molecules produced during the breakdown of fats, which occurs when stored sugars (such as glycogen) are unavailable. These short-term signs and symptoms of liver GSD 0 often improve when food is eaten and sugar levels in the body return to normal. The features of liver GSD 0 vary; they can be mild and go unnoticed for years, or they can include developmental delay and growth failure.
Hyperphosphatemia, polyuria, and seizures
MedGen UID:
343444
Concept ID:
C1855922
Disease or Syndrome
Hyperphosphatasia with mental retardation syndrome 1
MedGen UID:
383800
Concept ID:
C1855923
Disease or Syndrome
Hyperphosphatasia with mental retardation syndrome-1 is an autosomal recessive disorder characterized by mental retardation, various neurologic abnormalities such as seizures and hypotonia, and hyperphosphatasia. Other features include facial dysmorphism and variable degrees of brachytelephalangy (summary by Krawitz et al., 2010). Genetic Heterogeneity of Hyperphosphatasia with Mental Retardation Syndrome See also HPMRS2 (614749), caused by mutation in the PIGO gene (614730) on chromosome 9p13; HPMRS3 (614207), caused by mutation in the PGAP2 gene (615187) on chromosome 11p15; HPMRS4 (615716), caused by mutation in the PGAP3 gene (611801) on chromosome 17q12; and HPMRS5 (616025), caused by mutation in the PIGW gene (610275) on chromosome 17q12.
Hydroxylysinuria
MedGen UID:
343450
Concept ID:
C1855986
Disease or Syndrome
L-2-hydroxyglutaric aciduria
MedGen UID:
341029
Concept ID:
C1855995
Disease or Syndrome
2-hydroxyglutaric aciduria is a condition that causes progressive damage to the brain. The major types of this disorder are called D-2-hydroxyglutaric aciduria (D-2-HGA), L-2-hydroxyglutaric aciduria (L-2-HGA), and combined D,L-2-hydroxyglutaric aciduria (D,L-2-HGA). The main features of D-2-HGA are delayed development, seizures, weak muscle tone (hypotonia), and abnormalities in the largest part of the brain (the cerebrum), which controls many important functions such as muscle movement, speech, vision, thinking, emotion, and memory. Researchers have described two subtypes of D-2-HGA, type I and type II. The two subtypes are distinguished by their genetic cause and pattern of inheritance, although they also have some differences in signs and symptoms. Type II tends to begin earlier and often causes more severe health problems than type I. Type II may also be associated with a weakened and enlarged heart (cardiomyopathy), a feature that is typically not found with type I. L-2-HGA particularly affects a region of the brain called the cerebellum, which is involved in coordinating movements. As a result, many affected individuals have problems with balance and muscle coordination (ataxia). Additional features of L-2-HGA can include delayed development, seizures, speech difficulties, and an unusually large head (macrocephaly). Typically, signs and symptoms of this disorder begin during infancy or early childhood. The disorder worsens over time, usually leading to severe disability by early adulthood. Combined D,L-2-HGA causes severe brain abnormalities that become apparent in early infancy. Affected infants have severe seizures, weak muscle tone (hypotonia), and breathing and feeding problems. They usually survive only into infancy or early childhood.
Homocystinuria-Megaloblastic anemia due to defect in cobalamin metabolism, cblE complementation type
MedGen UID:
344640
Concept ID:
C1856057
Disease or Syndrome
The clinical manifestations of disorders of intracellular cobalamin metabolism can be highly variable even within a single complementation group. The prototype and best understood is cblC; it is also the most common of these disorders. The age of initial presentation of cblC spans a wide range, including: Newborns, who can have intrauterine growth retardation (IUGR) and microcephaly; Infants, who can have poor feeding, failure to thrive, pallor, and neurologic signs, and occasionally hemolytic uremic syndrome (HUS) and/or seizures including infantile spasms; Toddlers, who can have failure to thrive, poor head growth, cytopenias (including megaloblastic anemia), global developmental delay, encephalopathy, and neurologic signs such as hypotonia and seizures; and Adolescents and adults, who can have neuropsychiatric symptoms, progressive cognitive decline, and/or subacute combined degeneration of the spinal cord.
Homocysteinemia due to MTHFR deficiency
MedGen UID:
383829
Concept ID:
C1856058
Disease or Syndrome
Methylenetetrahydrofolate reductase deficiency is a common inborn error of folate metabolism. The phenotypic spectrum ranges from severe neurologic deterioration and early death to asymptomatic adults. In the classic form, both thermostable and thermolabile enzyme variants have been identified (Rosenblatt et al., 1992).
Holoprosencephaly 1
MedGen UID:
341060
Concept ID:
C1856096
Disease or Syndrome
Nonsyndromic holoprosencephaly is an abnormality of brain development that also affects the head and face. Normally, the brain divides into two halves (hemispheres) during early development. Holoprosencephaly occurs when the brain fails to divide properly into the right and left hemispheres. This condition is called nonsyndromic to distinguish it from other types of holoprosencephaly caused by genetic syndromes, chromosome abnormalities, or substances that cause birth defects (teratogens). The severity of nonsyndromic holoprosencephaly varies widely among affected individuals, even within the same family. Nonsyndromic holoprosencephaly can be grouped into four types according to the degree of brain division. From most to least severe, the types are known as alobar, semi-lobar, lobar, and middle interhemispheric variant (MIHV). In the most severe forms of nonsyndromic holoprosencephaly, the brain does not divide at all. These affected individuals have one central eye (cyclopia) and a tubular nasal structure (proboscis) located above the eye. Most babies with severe nonsyndromic holoprosencephaly die before birth or soon after. In the less severe forms, the brain is partially divided and the eyes are usually set close together (hypotelorism). The life expectancy of these affected individuals varies depending on the severity of symptoms. People with nonsyndromic holoprosencephaly often have a small head (microcephaly), although they can develop a buildup of fluid in the brain (hydrocephalus) that causes increased head size (macrocephaly). Other features may include an opening in the roof of the mouth (cleft palate) with or without a split in the upper lip (cleft lip), one front tooth (a single maxillary central incisor) instead of two, and a flat nasal bridge. The eyeballs may be abnormally small (microphthalmia) or absent (anophthalmia). Some individuals with nonsyndromic holoprosencephaly have a distinctive pattern of facial features, including a narrowing of the head at the temples, outside corners of the eyes that point upward (upslanting palpebral fissures), large ears, a short nose with upturned nostrils, and a broad and deep space between the nose and mouth (philtrum). In general, the severity of facial features is directly related to the severity of the brain abnormalities. However, individuals with mildly affected facial features can have severe brain abnormalities. Some people do not have apparent structural brain abnormalities but have some of the facial features associated with this condition. These individuals are considered to have a form of the disorder known as microform holoprosencephaly and are typically identified after the birth of a severely affected family member. Most people with nonsyndromic holoprosencephaly have developmental delay and intellectual disability. Affected individuals also frequently have a malfunctioning pituitary gland, which is a gland located at the base of the brain that produces several hormones. Because pituitary dysfunction leads to the partial or complete absence of these hormones, it can cause a variety of disorders. Most commonly, people with nonsyndromic holoprosencephaly and pituitary dysfunction develop diabetes insipidus, a condition that disrupts the balance between fluid intake and urine excretion. Dysfunction in other parts of the brain can cause seizures, feeding difficulties, and problems regulating body temperature, heart rate, and breathing. The sense of smell may be diminished (hyposmia) or completely absent (anosmia) if the part of the brain that processes smells is underdeveloped or missing.
Mowat-Wilson syndrome
MedGen UID:
341067
Concept ID:
C1856113
Disease or Syndrome
Mowat-Wilson syndrome (MWS) is characterized by the following: Distinctive facial features. Structural anomalies including: Hirschsprung disease. Genitourinary anomalies (particularly hypospadias in males). Congenital heart defects (particularly abnormalities of the pulmonary arteries and/or valves). Agenesis or hypogenesis of the corpus callosum. Eye defects (microphthalmia and Axenfeld anomaly). Functional differences including: Moderate to severe intellectual disability. Severe speech impairment with relative preservation of receptive language. Seizures. Growth retardation with microcephaly. Chronic constipation in those without Hirschsprung disease.
Hall Riggs mental retardation syndrome
MedGen UID:
341089
Concept ID:
C1856198
Disease or Syndrome
Growth retardation, small and puffy hands and feet, and eczema
MedGen UID:
343510
Concept ID:
C1856242
Disease or Syndrome
Gaucher disease type 3C
MedGen UID:
341563
Concept ID:
C1856476
Disease or Syndrome
Gaucher disease (GD) encompasses a continuum of clinical findings from a perinatal lethal disorder to an asymptomatic type. The identification of three major clinical types (1, 2, and 3) and two other subtypes (perinatal-lethal and cardiovascular) is useful in determining prognosis and management. GD type 1 is characterized by the presence of clinical or radiographic evidence of bone disease (osteopenia, focal lytic or sclerotic lesions, and osteonecrosis), hepatosplenomegaly, anemia and thrombocytopenia, lung disease, and the absence of primary central nervous system disease. GD types 2 and 3 are characterized by the presence of primary neurologic disease; in the past, they were distinguished by age of onset and rate of disease progression, but these distinctions are not absolute. Disease with onset before age two years, limited psychomotor development, and a rapidly progressive course with death by age two to four years is classified as GD type 2. Individuals with GD type 3 may have onset before age two years, but often have a more slowly progressive course, with survival into the third or fourth decade. The perinatal-lethal form is associated with ichthyosiform or collodion skin abnormalities or with nonimmune hydrops fetalis. The cardiovascular form is characterized by calcification of the aortic and mitral valves, mild splenomegaly, corneal opacities, and supranuclear ophthalmoplegia. Cardiopulmonary complications have been described with all the clinical subtypes, although varying in frequency and severity.
Fructose and galactose intolerance
MedGen UID:
341598
Concept ID:
C1856686
Disease or Syndrome
Epilepsy telangiectasia
MedGen UID:
384017
Concept ID:
C1856929
Disease or Syndrome
Epilepsy occipital calcifications
MedGen UID:
341654
Concept ID:
C1856930
Disease or Syndrome
Pontocerebellar hypoplasia type 4
MedGen UID:
384027
Concept ID:
C1856974
Disease or Syndrome
TSEN54-related pontocerebellar hypoplasia (PCH) includes three PCH types (PCH2, 4, and 5) that share characteristic neuroradiologic and neurologic findings. The three types (which differ mainly in life expectancy) were thought to be distinct entities before their molecular basis was known. Children with PCH2 usually succumb before age ten years, whereas those with PCH4 and 5 usually succumb as neonates. Children with PCH2 have generalized clonus, incoordination of sucking and swallowing, impaired motor and cognitive development with lack of voluntary motor development, central visual impairment, and an increased risk for malignant hyperthermia. Epilepsy is present in approximately 50%. Neonates with PCH4 often have seizures, multiple joint contractures (''arthrogryposis''), generalized clonus, and central respiratory impairment. PCH5, which resembles PCH4, has been described in one family.
Dysmyelination with jaundice
MedGen UID:
346526
Concept ID:
C1857143
Disease or Syndrome
Dopamine beta hydroxylase deficiency
MedGen UID:
341722
Concept ID:
C1857209
Disease or Syndrome
Dopamine beta-hydroxylase (DBH) deficiency is characterized by lack of sympathetic noradrenergic function but normal parasympathetic and sympathetic cholinergic function. Affected individuals exhibit profound deficits in autonomic regulation of cardiovascular function that predispose to orthostatic hypotension. Although DBH deficiency appears to be present from birth, the diagnosis is not generally recognized until late childhood. The combination of ptosis of the eyelids in infants and children, together with hypotension, is suggestive of the disease. In the perinatal period, DBH deficiency has been complicated by vomiting, dehydration, hypotension, hypothermia, and hypoglycemia requiring repeated hospitalization; children have reduced exercise capacity. By early adulthood, individuals have profound orthostatic hypotension, greatly reduced exercise tolerance, ptosis of the eyelids, and nasal stuffiness. Presyncopal symptoms include dizziness, blurred vision, dyspnea, nuchal discomfort, and chest pain. Life expectancy is unknown, but some affected individuals have lived beyond 60 years.
Donnai Barrow syndrome
MedGen UID:
347406
Concept ID:
C1857277
Disease or Syndrome
Donnai-Barrow syndrome (DBS) is characterized by typical craniofacial features (ocular hypertelorism, enlarged fontanelle), ocular findings (high myopia, retinal detachment, progressive vision loss, and iris coloboma), sensorineural hearing loss, agenesis of the corpus callosum, intellectual disability, and congenital diaphragmatic hernia (CDH) and/or omphalocele. Both inter- and intrafamilial phenotypic variability are observed.
Diaminopentanuria
MedGen UID:
347412
Concept ID:
C1857285
Disease or Syndrome
Polycystic lipomembranous osteodysplasia with sclerosing leukoencephalopathy
MedGen UID:
387795
Concept ID:
C1857316
Congenital Abnormality
Polycystic lipomembranous osteodysplasia with sclerosing leukoencephalopathy, commonly known as PLOSL, is a progressive disorder that affects the bones and brain. "Polycystic lipomembranous osteodysplasia" refers to cyst-like bone changes that can be seen on x-rays. "Sclerosing leukoencephalopathy" describes specific changes in the brain that are found in people with this disorder. The bone abnormalities associated with PLOSL usually become apparent in a person's twenties. In most affected individuals, pain and tenderness in the ankles and feet are the first symptoms of the disease. Several years later, broken bones (fractures) begin to occur frequently, particularly in bones of the ankles, feet, wrists, and hands. Bone pain and fractures are caused by thinning of the bones (osteoporosis) and cyst-like changes. These abnormalities weaken bones and make them more likely to break. The brain abnormalities characteristic of PLOSL typically appear in a person's thirties. Personality changes are among the first noticeable problems, followed by a loss of judgment, feelings of intense happiness (euphoria), a loss of inhibition, and poor concentration. These neurologic changes cause significant problems in an affected person's social and family life. As the disease progresses, it causes a severe decline in thinking and reasoning abilities (dementia). Affected people ultimately become unable to walk, speak, or care for themselves. People with this disease usually live only into their thirties or forties.
Digitorenocerebral syndrome
MedGen UID:
387800
Concept ID:
C1857345
Disease or Syndrome
TBC1D24-related disorders comprise a continuum that includes the following recognized phenotypes: DOORS syndrome (deafness, onychodystrophy, osteodystrophy, mental retardation, and seizures): profound sensorineural hearing loss, onychodystrophy, osteodystrophy, intellectual disability/developmental delay, and seizures. Familial infantile myoclonic epilepsy (FIME): early-onset myoclonic seizures, focal epilepsy, dysarthria, and mild-to-moderate intellectual disability. Progressive myoclonus epilepsy (PME): action myoclonus, tonic-clonic seizures, progressive neurologic decline, and ataxia. Early-infantile epileptic encephalopathy 16 (EIEE16): epileptiform EEG abnormalities which themselves are believed to contribute to progressive disturbance in cerebral function. Autosomal recessive nonsyndromic hearing loss, DFNB86: profound prelingual deafness . Autosomal dominant nonsyndromic hearing loss, DFNA65: slowly progressive deafness with onset in the third decade, initially affecting the high frequencies.
Dandy-Walker malformation with mental retardation, macrocephaly, myopia and brachytelephalangy
MedGen UID:
341752
Concept ID:
C1857352
Disease or Syndrome
Leigh syndrome, French Canadian type
MedGen UID:
387801
Concept ID:
C1857355
Disease or Syndrome
The French Canadian type of Leigh syndrome is an autosomal recessive severe neurologic disorder with onset in infancy. Features include delayed psychomotor development, mental retardation, mild dysmorphic facial features, hypotonia, ataxia, and the development of lesions in the brainstem and basal ganglia. Affected individuals tend to have episodic metabolic and/or neurologic crises in early childhood, which often lead to early death (summary by Debray et al., 2011). For a phenotypic description and a discussion of genetic heterogeneity of Leigh syndrome, see 256000.
Ventriculomegaly with cystic kidney disease
MedGen UID:
346584
Concept ID:
C1857423
Disease or Syndrome
Ventriculomegaly with cystic kidney disease is a severe autosomal recessive developmental disorder characterized by onset in utero of dilated cerebral ventricles and microscopic renal tubular cysts. The pregnancies of affected individuals are associated with increased alpha-fetoprotein (AFP). Most affected pregnancies have been terminated (summary by Slavotinek et al., 2015). See also 602200 for a disorder characterized by ventriculomegaly and defects of the radius and kidney.
Craniosynostosis-mental retardation-clefting syndrome
MedGen UID:
387829
Concept ID:
C1857472
Disease or Syndrome
Craniosynostosis with fibular aplasia
MedGen UID:
347468
Concept ID:
C1857492
Disease or Syndrome
Craniofacial dyssynostosis
MedGen UID:
347473
Concept ID:
C1857511
Disease or Syndrome
Temtamy syndrome
MedGen UID:
347474
Concept ID:
C1857512
Disease or Syndrome
Temtamy syndrome is a mental retardation/multiple congenital anomaly syndrome characterized by variable craniofacial dysmorphism, ocular coloboma, seizures, and brain abnormalities, including abnormalities of the corpus callosum and thalamus (summary by Akizu et al., 2013).
Convulsive disorder, familial, with prenatal or early onset
MedGen UID:
387859
Concept ID:
C1857575
Disease or Syndrome
COACH syndrome
MedGen UID:
387879
Concept ID:
C1857662
Disease or Syndrome
COACH syndrome is an autosomal recessive disorder characterized by mental retardation, ataxia due to cerebellar hypoplasia, and hepatic fibrosis. Other features, such as coloboma and renal cysts, may be variable. COACH syndrome is considered by some to be a subtype of Joubert syndrome (JBTS; 213300) with congenital hepatic fibrosis. Identification of liver disease in these patients is critical because some may develop complications such as portal hypertension with fatal variceal bleeding (Brancati et al., 2008; Doherty et al., 2010).
Kallmann syndrome 4
MedGen UID:
387893
Concept ID:
C1857720
Disease or Syndrome
Isolated gonadotropin-releasing hormone (GnRH) deficiency (IGD) is characterized by inappropriately low serum concentrations of the gonadotropins LH (luteinizing hormone) and FSH (follicle-stimulating hormone) in the setting of hypogonadism. IGD is associated with a normal sense of smell (normosmic IGD) in approximately 40% of affected individuals and an impaired sense of smell (Kallmann syndrome [KS]) in approximately 60%. IGD can first be apparent in infancy, adolescence, or adulthood. Infant boys with congenital (i.e., present at birth) IGD often have micropenis and cryptorchidism. Adolescents and adults with IGD have clinical evidence of hypogonadism and incomplete sexual maturation on physical examination. Adult males with IGD tend to have prepubertal testicular volume (i.e., <4 mL), absence of secondary sexual features (e.g., facial and axillary hair growth, deepening of the voice), decreased muscle mass, diminished libido, erectile dysfunction, and infertility. Adult females have little or no breast development and primary amenorrhea. Although skeletal maturation is delayed, the rate of linear growth is usually normal except for the absence of a distinct pubertal growth spurt.
Neurodegeneration with brain iron accumulation 2b
MedGen UID:
346658
Concept ID:
C1857747
Disease or Syndrome
PLA2G6-associated neurodegeneration (PLAN) comprises a continuum of three phenotypes with overlapping clinical and radiologic features: Classic infantile neuroaxonal dystrophy (INAD). Atypical neuroaxonal dystrophy (atypical NAD). PLA2G6-related dystonia-parkinsonism. INAD usually begins between ages six months and three years with developmental regression, hypotonia, progressive psychomotor delay, and progressive spastic tetraparesis. Strabismus, nystagmus, and optic atrophy are common. Disease progression is rapid. Many affected children never learn to walk or lose the ability shortly after attaining it. Severe spasticity, progressive cognitive decline, and visual impairment typically result in death during the first decade. Atypical NAD shows more phenotypic variability than INAD. In general, onset is in early childhood but can be as late as the end of the second decade. The presenting signs may be gait instability or ataxia (as in the classic form) or speech delay and autistic features, which are sometimes the only evidence of disease for a year or more. The course is fairly stable during early childhood and resembles static encephalopathy but is followed by neurologic deterioration between ages seven and 12 years. PLA2G6-related dystonia-parkinsonism presents with subacute onset of dystonia-parkinsonism in late adolescence/early adulthood. Other findings are eye movement abnormalities, pyramidal tract signs, and marked cognitive decline.
Pontocerebellar hypoplasia type 5
MedGen UID:
341845
Concept ID:
C1857762
Disease or Syndrome
Pontocerebellar hypoplasia (PCH) refers to a heterogeneous group of disorders characterized by an abnormally small cerebellum and brainstem (summary by Patel et al., 2006). For a phenotypic description and a discussion of genetic heterogeneity of pontocerebellar hypoplasia, see PCH1 (607596).
Leber congenital amaurosis 10
MedGen UID:
346672
Concept ID:
C1857821
Congenital Abnormality
Leber congenital amaurosis (LCA), a severe dystrophy of the retina, typically becomes evident in the first year of life. Visual function is usually poor and often accompanied by nystagmus, sluggish or near-absent pupillary responses, photophobia, high hyperopia, and keratoconus. Visual acuity is rarely better than 20/400. A characteristic finding is Franceschetti's oculo-digital sign, comprising eye poking, pressing, and rubbing. The appearance of the fundus is extremely variable. While the retina may initially appear normal, a pigmentary retinopathy reminiscent of retinitis pigmentosa is frequently observed later in childhood. The electroretinogram (ERG) is characteristically "nondetectable" or severely subnormal.
Alzheimer disease, familial early-onset, with coexisting amyloid and prion pathology
MedGen UID:
341884
Concept ID:
C1857933
Disease or Syndrome
Huntington disease-like 3
MedGen UID:
347622
Concept ID:
C1858114
Disease or Syndrome
As its name suggests, a Huntington disease-like (HDL) syndrome is a condition that resembles Huntington disease. Researchers have described four HDL syndromes, designated Huntington disease-like 1 (HDL1) through Huntington disease-like 4 (HDL4). These progressive brain disorders are characterized by uncontrolled movements, emotional problems, and loss of thinking ability. HDL syndromes occur in people with the characteristic features of Huntington disease who do not have a mutation in HD, the gene typically associated with that disorder. HDL1, HDL2, and HDL4 usually appear in early to mid-adulthood, although they can begin earlier in life. The first signs and symptoms of these conditions often include irritability, emotional problems, small involuntary movements, poor coordination, and trouble learning new information or making decisions. Many affected people develop involuntary jerking or twitching movements known as chorea. As the disease progresses, these abnormal movements become more pronounced. Affected individuals may develop problems with walking, speaking, and swallowing. People with these disorders also experience changes in personality and a decline in thinking and reasoning abilities. Individuals with an HDL syndrome can live for a few years to more than a decade after signs and symptoms begin. HDL3 begins much earlier in life than most of the other HDL syndromes (usually around age 3 or 4). Affected children experience a decline in thinking ability, difficulties with movement and speech, and seizures. Because HDL3 has a somewhat different pattern of signs and symptoms and a different pattern of inheritance, researchers are unsure whether it belongs in the same category as the other HDL syndromes.
Craniosynostosis 2
MedGen UID:
346753
Concept ID:
C1858160
Disease or Syndrome
Craniosynostosis is a primary abnormality of skull growth involving premature fusion of the cranial sutures such that the growth velocity of the skull often cannot match that of the developing brain. This produces skull deformity and, in some cases, raises intracranial pressure, which must be treated promptly to avoid permanent neurodevelopmental disability (Fitzpatrick, 2013). For a discussion of genetic heterogeneity of craniosynostosis, see CRS1 (123100).
Epilepsy, partial, with variable foci
MedGen UID:
348951
Concept ID:
C1858477
Disease or Syndrome
FFEVF is an autosomal dominant form of epilepsy characterized by focal seizures arising from different cortical regions in different family members. Many patients have an aura and show automatisms during the seizures, whereas others may have nocturnal seizures. There is often secondary generalization. Some patients show abnormal interictal EEG, and some patients may have intellectual disability or autism spectrum disorders. Seizure onset usually occurs in the first or second decades, although later onset has been reported, and there is phenotypic variability within families. Penetrance of the disorder is incomplete (summary by Klein et al., 2012). Detailed electrophysiologic, brain imaging, and/or histologic studies have indicated that some patients have subtle or clear evidence of focal cortical dysplasia (FCD) (Baulac et al., 2015).
Spastic paraplegia 11, autosomal recessive
MedGen UID:
388073
Concept ID:
C1858479
Disease or Syndrome
Spastic paraplegia 11 (SPG11) is characterized by progressive spasticity and weakness of the lower limbs frequently associated with the following: mild intellectual disability with learning difficulties in childhood and/or progressive cognitive decline; peripheral neuropathy; pseudobulbar involvement; and increased reflexes in the upper limbs. Less frequent findings include: cerebellar signs (ataxia, nystagmus, saccadic pursuit); retinal degeneration; pes cavus; scoliosis; and parkinsonism. Onset occurs mainly during infancy or adolescence (range: age 1-31 years). Most affected individuals become wheelchair bound one or two decades after disease onset.
Primary autosomal recessive microcephaly 2
MedGen UID:
346929
Concept ID:
C1858535
Disease or Syndrome
Primary autosomal recessive microcephalies (MCPH) and Seckel syndrome (SCKS) spectrum disorders are characterized by microcephaly and the absence of visceral malformations. Although MCHP and SCKS were previously distinguished by height (maximum height in SCKS was equivalent to the minimum height in MCPH), stature is no longer a discriminating feature, leading to the conclusion that these phenotypes constitute a spectrum rather than distinct entities. Microcephaly is characterized by: Onset during the second trimester of gestation; Occipito-frontal head circumference (OFC) at birth equal to or less than -2 SD below the mean for sex, age, and ethnicity; Slower than average increase in OFC after birth. Variable findings in the MCPH-SCKS spectrum disorders include: Brain structure (which is normal in the majority); Degree of cognitive impairment (usually mild to moderate without significant motor delay in the majority of persons with MCPH and more severe in those with SCKS and MCPH with brain malformations); Degree of short stature; Craniosynostosis (which may be secondary to poor brain growth).
Familial encephalopathy with neuroserpin inclusion bodies
MedGen UID:
346965
Concept ID:
C1858680
Disease or Syndrome
Familial encephalopathy with neuroserpin inclusion bodies (FENIB) is a disorder that causes progressive dysfunction of the brain (encephalopathy). It is characterized by a loss of intellectual functioning (dementia) and seizures. At first, affected individuals may have difficulty sustaining attention and concentrating. They may experience repetitive thoughts, speech, or movements. As the condition progresses, their personality changes and judgment, insight, and memory become impaired. Affected people lose the ability to perform the activities of daily living, and most eventually require comprehensive care. The signs and symptoms of FENIB vary in their severity and age of onset. In severe cases, the condition causes seizures and episodes of sudden, involuntary muscle jerking or twitching (myoclonus) in addition to dementia. These signs can appear as early as a person's teens. Less severe cases are characterized by a progressive decline in intellectual functioning beginning in a person's forties or fifties.
Chudley-McCullough syndrome
MedGen UID:
347699
Concept ID:
C1858695
Disease or Syndrome
Chudley-McCullough syndrome is an autosomal recessive neurologic disorder characterized by early-onset sensorineural deafness and specific brain anomalies on MRI, including hypoplasia of the corpus callosum, enlarged cysterna magna with mild focal cerebellar dysplasia, and nodular heterotopia. Some patients have hydrocephalus. Psychomotor development is normal (summary by Alrashdi et al., 2011).
Megalencephalic leukoencephalopathy with subcortical cysts 1
MedGen UID:
347006
Concept ID:
C1858854
Congenital Abnormality
The classic phenotype of megalencephalic leukoencephalopathy with subcortical cysts (MLC) is characterized by early-onset macrocephaly, often in combination with mild gross motor developmental delay and seizures; gradual onset of ataxia, spasticity, and sometimes extrapyramidal findings; and usually late onset of mild mental deterioration. Macrocephaly, observed in all individuals, may be present at birth but more frequently develops during the first year of life. The degree of macrocephaly is variable and can be as great as 4 to 6 SD above the mean in some individuals. After the first year of life, head growth rate normalizes and growth follows a line parallel to the 98th percentile, usually several centimeters above it. Almost all individuals have epilepsy from an early age. Initial mental and motor development is normal in most cases. Walking is often unstable, followed by ataxia of the trunk and extremities, then minor signs of pyramidal dysfunction and brisk deep-tendon stretch reflexes. Mental deterioration is late and mild. Severity ranges from independent walking for a few years only to independent walking in the fifth decade. Some individuals have died in their teens or twenties; others are alive in their forties. An atypical improving phenotype has a similar initial presentation without mental or motor regression, followed by an improving clinical course: motor and cognitive functions improve or normalize; macrocephaly usually persists, but some children become normocephalic; hypotonia and clumsiness may persist in some or neurologic examination may become normal. Some have intellectual disability that is stable with or without autism.
Leukoencephalopathy with vanishing white matter
MedGen UID:
347037
Concept ID:
C1858991
Disease or Syndrome
Childhood ataxia with central nervous system hypomyelination/vanishing white matter disease (CACH/VWM) is characterized by ataxia, spasticity, and variable optic atrophy. The phenotypic range includes a prenatal/congenital form, a subacute infantile form (onset age <1 year), an early childhood onset form (onset age 1-5 years), a late childhood /juvenile onset form (onset age 5-15 years), and an adult onset form. The prenatal/congenital form is characterized by severe encephalopathy. In the later onset forms initial motor and intellectual development is normal or mildly delayed followed by neurologic deterioration with a chronic progressive or subacute course. Chronic progressive decline can be exacerbated by rapid deterioration during febrile illnesses or following head trauma or major surgical procedures, or by acute psychological stresses such as extreme fright.
Congenital central hypoventilation
MedGen UID:
347052
Concept ID:
C1859049
Disease or Syndrome
Congenital central hypoventilation syndrome (CCHS) is a rare disorder of respiratory and autonomic regulation. It is typically characterized by a classic presentation in newborns and, rarely, a milder later-onset (LO-CCHS) presentation in toddlers, children, and adults. Classic CCHS presents in newborns as: Apparent hypoventilation with monotonous respiratory rates and shallow breathing either during sleep only or while awake as well as asleep; Autonomic nervous system dysregulation (ANSD); and In some individuals, altered development of neural crest-derived structures (i.e., Hirschsprung disease) and/or tumors of neural crest origin (neuroblastoma, ganglioneuroma, and ganglioneuroblastoma). Individuals with CCHS who have been diagnosed as newborns and ventilated conservatively and consistently throughout childhood have now reached the age of 20 to 30 years; they are highly functional and live independently. LO-CCHS manifests as nocturnal alveolar hypoventilation and mild ANSD. Individuals with LO-CCHS who were not identified until age 20 years or older have now reached the age of 30 to 55 years.
Choroid plexus calcification with mental retardation
MedGen UID:
395174
Concept ID:
C1859092
Disease or Syndrome
Rhizomelic chondrodysplasia punctata type 1
MedGen UID:
347072
Concept ID:
C1859133
Disease or Syndrome
Rhizomelic chondrodysplasia punctata type 1 (RCDP1) classic type, a peroxisome biogenesis disorder (PBD), is characterized by proximal shortening of the humerus and to a lesser degree the femur (rhizomelia), punctate calcifications in cartilage with epiphyseal and metaphyseal abnormalities (chondrodysplasia punctata, or CDP), coronal clefts of the vertebral bodies, and cataracts that are usually present at birth or appear in the first few months of life. Birth weight, length, and head circumference are often at the lower range of normal; postnatal growth deficiency is profound. Intellectual disability is severe, and the majority of children develop seizures. Most affected children do not survive the first decade of life; a proportion die in the neonatal period. A milder phenotype in which all affected individuals have congenital cataracts and chondrodysplasia is now recognized; some do not have rhizomelia, and some have less severe intellectual disability and growth deficiency.
Griscelli syndrome type 1
MedGen UID:
347092
Concept ID:
C1859194
Disease or Syndrome
Griscelli syndrome type 1 (GS1) represents hypomelanosis with a primary neurologic deficit and without immunologic impairment or manifestations of hemophagocytic syndrome (Menasche et al., 2002). Griscelli syndrome with immune impairment, or Griscelli syndrome type 2 (607624), is caused by mutation in the RAB27A gene (603868). Griscelli syndrome type 3 (609227), characterized by hypomelanosis with no immunologic or neurologic manifestations, can be caused by mutation in the melanophilin (MLPH; 606526) or MYO5A genes. Griscelli syndrome is a rare autosomal recessive disorder that results in pigmentary dilution of the skin and hair, the presence of large clumps of pigment in hair shafts, and an accumulation of melanosomes in melanocytes. While most patients also develop hemophagocytic syndrome, leading to death in the absence of bone marrow transplantation (Menasche et al., 2000), some show severe neurologic impairment early in life without apparent immune abnormalities. Bahadoran et al. (2003) characterized GS1 as comprising hypomelanosis and severe central nervous system dysfunction, corresponding to the 'dilute' phenotype in the mouse, and GS2 as comprising hypomelanosis and lymphohistiocytotic hemophagocytosis, corresponding to the 'ashen' phenotype in mouse. Anikster et al. (2002), Menasche et al. (2002), Huizing et al. (2002), and Bahadoran et al. (2003, 2003) suggested that Elejalde syndrome (256710) in some patients and GS1 represent the same entity.
Peroxisome biogenesis disorder 2A
MedGen UID:
347830
Concept ID:
C1859228
Disease or Syndrome
The peroxisome biogenesis disorder (PBD) Zellweger syndrome (ZS) is an autosomal recessive multiple congenital anomaly syndrome. Affected children present in the newborn period with profound hypotonia, seizures, and inability to feed. Characteristic craniofacial anomalies, eye abnormalities, neuronal migration defects, hepatomegaly, and chondrodysplasia punctata are present. Children with this condition do not show any significant development and usually die in the first year of life (summary by Steinberg et al., 2006). For a complete phenotypic description and a discussion of genetic heterogeneity of Zellweger syndrome, see 214100. Individuals with PBDs of complementation group 2 (CG2) have mutations in the PEX5 gene. For information on the history of PBD complementation groups, see 214100.
CEREBELLOPARENCHYMAL DISORDER II
MedGen UID:
395223
Concept ID:
C1859299
Disease or Syndrome
Cerebellar vermis aplasia with associated features suggesting Smith-Lemli-Opitz syndrome and Meckel syndrome
MedGen UID:
347120
Concept ID:
C1859300
Disease or Syndrome
Camptodactyly syndrome Guadalajara type 1
MedGen UID:
395241
Concept ID:
C1859359
Disease or Syndrome
BRACHYDACTYLY, TYPE A2, WITH MICROCEPHALY
MedGen UID:
395250
Concept ID:
C1859393
Disease or Syndrome
Bowen-Conradi syndrome
MedGen UID:
349160
Concept ID:
C1859405
Disease or Syndrome
Bowen-Conradi syndrome is a disorder that affects many parts of the body and is usually fatal in infancy. Affected individuals have a low birth weight, experience feeding problems, and grow very slowly. Their head is unusually small overall (microcephaly), but is longer than expected compared with its width (dolicocephaly). Characteristic facial features include a prominent, high-bridged nose and an unusually small jaw (micrognathia) and chin. Affected individuals typically have pinky fingers that are curved toward or away from the ring finger (fifth finger clinodactyly) or permanently flexed (camptodactyly), feet with soles that are rounded outward (rocker-bottom feet), and restricted joint movement. Other features that occur in some affected individuals include seizures; structural abnormalities of the kidneys, heart, brain, or other organs; and an opening in the lip (cleft lip) with or without an opening in the roof of the mouth (cleft palate). Affected males may have the opening of the urethra on the underside of the penis (hypospadias) or undescended testes (cryptorchidism). Babies with Bowen-Conradi syndrome do not achieve developmental milestones such as smiling or sitting, and they usually do not survive more than 6 months.
Microcephalic osteodysplastic primordial dwarfism type 2
MedGen UID:
347148
Concept ID:
C1859451
Disease or Syndrome
Microcephalic osteodysplastic primordial dwarfism type II is characterized by intrauterine growth retardation, severe proportionate short stature, and microcephaly. It is distinct from Seckel syndrome (see 210600) by more severe growth retardation, radiologic abnormalities, and absent or mild mental retardation (summary by Willems et al., 2010).
Osteodysplastic primordial dwarfism, type 1
MedGen UID:
347149
Concept ID:
C1859452
Congenital Abnormality
Microcephalic osteodysplastic primordial dwarfism type I is a severe autosomal recessive skeletal dysplasia characterized by dwarfism, microcephaly, and neurologic abnormalities, including mental retardation, brain malformations, and ocular/auditory sensory deficits. Patients often die in early childhood (summary by Pierce and Morse, 2012).
3-@METHYLCROTONYL-CoA CARBOXYLASE 1 DEFICIENCY
MedGen UID:
347162
Concept ID:
C1859500
Disease or Syndrome
Berry aneurysm, cirrhosis, pulmonary emphysema, and cerebral calcification
MedGen UID:
347170
Concept ID:
C1859519
Disease or Syndrome
Feigenbaum Bergeron Richardson syndrome
MedGen UID:
349198
Concept ID:
C1859596
Disease or Syndrome
Ataxia with myoclonic epilepsy and presenile dementia
MedGen UID:
347924
Concept ID:
C1859646
Disease or Syndrome
Illum syndrome
MedGen UID:
349231
Concept ID:
C1859711
Disease or Syndrome
Angiomatosis, diffuse corticomeningeal, of Divry and Van Bogaert
MedGen UID:
347234
Concept ID:
C1859783
Disease or Syndrome
ACTH resistance
MedGen UID:
395383
Concept ID:
C1859974
Disease or Syndrome
Familial glucocorticoid deficiency is an autosomal recessive disorder resulting from defects in the action of adrenocorticotropic hormone (ACTH) to stimulate glucocorticoid synthesis in the adrenal. Production of mineralocorticoids by the adrenal is normal. Patients present in early life with low or undetectable cortisol and, because of the failure of the negative feedback loop to the pituitary and hypothalamus, grossly elevated ACTH levels (summary by Clark et al., 2009). Genetic Heterogeneity of Familial Glucocorticoid Deficiency Familial glucocorticoid deficiency-2 (GCCD2; 607398) is caused by mutation in the MRAP gene (699196) on chromosome 21q22. GCCD3 has been mapped to chromosome 8q11.2-q13.2. GCCD4 (614736) is caused by mutation in the NNT gene (607878) on chromosome 5p12.
Vasculopathy, retinal, with cerebral leukodystrophy
MedGen UID:
348124
Concept ID:
C1860518
Disease or Syndrome
Retinal vasculopathy with cerebral leukodystrophy is an adult-onset autosomal dominant disorder involving the microvessels of the brain and resulting in central nervous system degeneration with progressive loss of vision, stroke, motor impairment, and cognitive decline. Death occurs in most patients 5 to 10 years after onset. A subset of affected individuals have systemic vascular involvement evidenced by Raynaud's phenomenon, micronodular cirrhosis, and glomerular dysfunction (summary by Richards et al., 2007).
Cochleosaccular degeneration of the inner ear and progressive cataracts
MedGen UID:
348378
Concept ID:
C1861512
Disease or Syndrome
Choreoathetosis, familial inverted
MedGen UID:
348393
Concept ID:
C1861569
Disease or Syndrome
Cerebral cavernous malformation
MedGen UID:
349362
Concept ID:
C1861784
Disease or Syndrome
Cerebral cavernous malformations (CCMs) are vascular malformations in the brain and spinal cord comprising closely clustered, enlarged capillary channels (caverns) with a single layer of endothelium without mature vessel wall elements or normal intervening brain parenchyma. The diameter of CCMs ranges from a few millimeters to several centimeters. CCMs increase or decrease in size and increase in number over time. Hundreds of lesions may be identified, depending on the person’s age and the quality and type of brain imaging used. Although CCMs have been reported in infants and children, the majority become evident between the second and fifth decades with findings such as seizures, focal neurologic deficits, nonspecific headaches, and cerebral hemorrhage. Up to 50% of individuals with CCM remain symptom free throughout their lives. Familial cerebral cavernous malformation (FCCM) is defined as the occurrence of CCMs in at least two family members and/or the presence of multiple CCMs and/or the presence of a disease-causing mutation in one of the three genes in which mutations are known to cause familial CCM. Cutaneous vascular lesions are found in 9% of those with FCCM and retinal vascular lesions in almost 5%.
Idiopathic basal ganglia calcification childhood-onset
MedGen UID:
396262
Concept ID:
C1861967
Disease or Syndrome
Bilateral striopallidodentate calcinosis, also known as idiopathic basal ganglia calcification (IBGC), is characterized by the accumulation of calcium deposits in different brain regions and is associated with a neurodegenerative clinical phenotype. The changes seen in IBGC occur in the absence of calcium or parathyroid hormone (PTH; 168450) metabolic disorders, such as hypoparathyroidism (see 146200) or pseudohypoparathyroidism (PHP; see 103580). See also the adult-onset form (213600), which is sometimes erroneously referred to as 'Fahr disease.'
Ataxia, spastic, with congenital miosis
MedGen UID:
354750
Concept ID:
C1862441
Disease or Syndrome
Arteritis, familial granulomatous, with juvenile polyarthritis
MedGen UID:
349529
Concept ID:
C1862510
Disease or Syndrome
Hemangiomatosis, Disseminated
MedGen UID:
349627
Concept ID:
C1862898
Disease or Syndrome
Alopecia, epilepsy, pyorrhea, mental subnormality
MedGen UID:
350833
Concept ID:
C1863090
Disease or Syndrome
Young Simpson syndrome
MedGen UID:
350209
Concept ID:
C1863557
Disease or Syndrome
Say-Barber-Biesecker-Young-Simpson syndrome, a variant of Ohdo syndrome (249620), is characterized by distinctive facial appearance with severe blepharophimosis, an immobile mask-like face, a bulbous nasal tip, and a small mouth with a thin upper lip. The condition presents in infancy with severe hypotonia and feeding problems. Associated skeletal problems include joint laxity, abnormally long thumbs and great toes, and dislocated or hypoplastic patellae. Structural cardiac defects are present in around 50% of cases, and dental anomalies, including small and pointed teeth, are common. Many affected individuals have abnormalities of thyroid structure or function. YSS is usually associated with severe mental retardation, delayed motor milestones, and significantly impaired speech (summary by Clayton-Smith et al., 2011). Genitopatellar syndrome (606170) is an allelic disorder with overlapping features.
Acromelic frontonasal dysostosis
MedGen UID:
350933
Concept ID:
C1863616
Disease or Syndrome
Verloes et al. (1992) described a rare variant of frontonasal dysplasia (see FND1, 136760), designated acromelic frontonasal dysplasia (AFND), in which similar craniofacial anomalies are associated with variable central nervous system malformations and limb defects including tibial hypoplasia/aplasia, talipes equinovarus, and preaxial polydactyly of the feet.
Hemophagocytic lymphohistiocytosis, familial, 2
MedGen UID:
400366
Concept ID:
C1863727
Disease or Syndrome
Familial hemophagocytic lymphohistiocytosis (FHL) is characterized by proliferation and infiltration of hyperactivated macrophages and T-lymphocytes manifesting as acute illness with prolonged fever, cytopenias, and hepatosplenomegaly. Onset is typically within the first months or years of life and, on occasion, in utero, although later childhood or adult onset is more common than previously suspected. Neurologic abnormalities may be present initially or may develop later; they may include increased intracranial pressure, irritability, neck stiffness, hypotonia, hypertonia, convulsions, cranial nerve palsies, ataxia, hemiplegia, quadriplegia, blindness, and coma. Rash and lymphadenopathy are less common. Other findings include liver dysfunction and bone marrow hemophagocytosis. The median survival of children with typical FHL, without treatment, is less than two months; progression of hemophagocytic lymphohistiocytosis and infection account for the majority of deaths in untreated individuals.
Hemophagocytic lymphohistiocytosis, familial, 4
MedGen UID:
350245
Concept ID:
C1863728
Disease or Syndrome
Familial hemophagocytic lymphohistiocytosis (FHL) is characterized by proliferation and infiltration of hyperactivated macrophages and T-lymphocytes manifesting as acute illness with prolonged fever, cytopenias, and hepatosplenomegaly. Onset is typically within the first months or years of life and, on occasion, in utero, although later childhood or adult onset is more common than previously suspected. Neurologic abnormalities may be present initially or may develop later; they may include increased intracranial pressure, irritability, neck stiffness, hypotonia, hypertonia, convulsions, cranial nerve palsies, ataxia, hemiplegia, quadriplegia, blindness, and coma. Rash and lymphadenopathy are less common. Other findings include liver dysfunction and bone marrow hemophagocytosis. The median survival of children with typical FHL, without treatment, is less than two months; progression of hemophagocytic lymphohistiocytosis and infection account for the majority of deaths in untreated individuals.
Neuronal intranuclear inclusion disease
MedGen UID:
355075
Concept ID:
C1863843
Disease or Syndrome
Neuronal intranuclear inclusion disease (NIID) is characterized pathologically by eosinophilic intranuclear inclusions in neurons of the peripheral, central, and autonomic nervous systems associated with varying degrees of neuronal loss. Symptoms usually begin in childhood but adult-onset cases have also been described. Clinical expression is variable, depending on the sites of maximal neuronal loss, but is usually a multisystem degenerative process of the central nervous system or a visceral neuropathy (summary by Kimber et al., 1998). See the neuronal form of intestinal pseudoobstruction (243180).
Megalencephaly polymicrogyria-polydactyly hydrocephalus syndrome
MedGen UID:
355095
Concept ID:
C1863924
Disease or Syndrome
This disorder comprises megalencephaly, hydrocephalus, and polymicrogyria; polydactyly may also be seen. There is considerable phenotypic similarity between this disorder and the megalencephaly-capillary malformation syndrome (MCAP; 602501) (summary by Gripp et al., 2009). Genetic Heterogeneity the Megalencephaly-Polymicrogyria-Polydactyly-Hydrocephalus Syndrome See also MPPH2 (615937), caused by mutation in the AKT3 gene (611223) on chromosome 1q43-q44; and MPPH3 (615938), caused by mutation in the CCND2 gene (123833) on chromosome 12p13.
Cerebral cavernous malformations 3
MedGen UID:
355121
Concept ID:
C1864040
Disease or Syndrome
Cerebral cavernous malformations (CCMs) are vascular malformations in the brain and spinal cord comprising closely clustered, enlarged capillary channels (caverns) with a single layer of endothelium without mature vessel wall elements or normal intervening brain parenchyma. The diameter of CCMs ranges from a few millimeters to several centimeters. CCMs increase or decrease in size and increase in number over time. Hundreds of lesions may be identified, depending on the person’s age and the quality and type of brain imaging used. Although CCMs have been reported in infants and children, the majority become evident between the second and fifth decades with findings such as seizures, focal neurologic deficits, nonspecific headaches, and cerebral hemorrhage. Up to 50% of individuals with CCM remain symptom free throughout their lives. Familial cerebral cavernous malformation (FCCM) is defined as the occurrence of CCMs in at least two family members and/or the presence of multiple CCMs and/or the presence of a disease-causing mutation in one of the three genes in which mutations are known to cause familial CCM. Cutaneous vascular lesions are found in 9% of those with FCCM and retinal vascular lesions in almost 5%.
Cerebral cavernous malformations 2
MedGen UID:
400438
Concept ID:
C1864041
Disease or Syndrome
Cerebral cavernous malformations (CCMs) are vascular malformations in the brain and spinal cord comprising closely clustered, enlarged capillary channels (caverns) with a single layer of endothelium without mature vessel wall elements or normal intervening brain parenchyma. The diameter of CCMs ranges from a few millimeters to several centimeters. CCMs increase or decrease in size and increase in number over time. Hundreds of lesions may be identified, depending on the person’s age and the quality and type of brain imaging used. Although CCMs have been reported in infants and children, the majority become evident between the second and fifth decades with findings such as seizures, focal neurologic deficits, nonspecific headaches, and cerebral hemorrhage. Up to 50% of individuals with CCM remain symptom free throughout their lives. Familial cerebral cavernous malformation (FCCM) is defined as the occurrence of CCMs in at least two family members and/or the presence of multiple CCMs and/or the presence of a disease-causing mutation in one of the three genes in which mutations are known to cause familial CCM. Cutaneous vascular lesions are found in 9% of those with FCCM and retinal vascular lesions in almost 5%.
Congenital disorder of glycosylation type 1C
MedGen UID:
400469
Concept ID:
C1864178
Disease or Syndrome
Congenital disorders of N-linked glycosylation (abbreviated here as CDG-N-linked), are a group of disorders of N-linked oligosaccharides caused by deficiency in 42 different enzymes in the N-linked synthetic pathway. Most commonly, the disorders begin in infancy; manifestations range from severe developmental delay and hypotonia with multiple organ system involvement to hypoglycemia and protein-losing enteropathy with normal development. However, most types have been described in only a few individuals, and thus understanding of the phenotypes is limited. In PMM2-CDG (CDG-Ia), the most common type reported, the clinical presentation and course are highly variable, ranging from death in infancy to mild involvement in adults.
Chromosome 16p13.3 deletion syndrome
MedGen UID:
350477
Concept ID:
C1864648
Disease or Syndrome
Gaucher disease, atypical, due to saposin C deficiency
MedGen UID:
350479
Concept ID:
C1864651
Disease or Syndrome
Growth and mental retardation, mandibulofacial dysostosis, microcephaly, and cleft palate
MedGen UID:
355264
Concept ID:
C1864652
Disease or Syndrome
Mandibulofacial dysostosis with microcephaly (MFDM) is characterized by malar and mandibular hypoplasia; microcephaly (congenital or postnatal onset); malformations of the pinna, auditory canal, and/or middle ear (ossicles and semi-circular canals) with associated conductive hearing loss; and distinctive facial features (metopic ridge, up- or downslanting palpebral fissures, prominent glabella, broad nasal bridge, bulbous nasal tip, and everted lower lip). Associated craniofacial malformations may include cleft palate, choanal atresia, and facial asymmetry. Intellectual disability is a prominent feature. Major extracranial malformations include: esophageal atresia (~40%), congenital heart disease (~40%), and thumb abnormalities (~25%). Short stature is present in approximately one third of individuals.
Autosomal dominant progressive external ophthalmoplegia with mitochondrial DNA deletions 4
MedGen UID:
350480
Concept ID:
C1864668
Disease or Syndrome
Progressive external ophthalmoplegia-4 is an autosomal dominant form of mitochondrial disease that variably affects skeletal muscle, the nervous system, the liver, and the gastrointestinal tract. Age at onset ranges from infancy to adulthood. The phenotype ranges from relatively mild, with adult-onset skeletal muscle weakness and weakness of the external eye muscles, to severe, with a multisystem disorder characterized by delayed psychomotor development, lactic acidosis, constipation, and liver involvement (summary by Young et al., 2011). For a general phenotypic description and a discussion of genetic heterogeneity of autosomal dominant progressive external ophthalmoplegia, see PEOA1 (157640).
Ceroid lipofuscinosis neuronal 10
MedGen UID:
350481
Concept ID:
C1864669
Disease or Syndrome
The neuronal ceroid-lipofuscinoses (NCLs) are a group of inherited, neurodegenerative, lysosomal storage disorders characterized by progressive intellectual and motor deterioration, seizures, and early death. Visual gvhmloss is a feature of most forms. Clinical phenotypes have been characterized traditionally according to the age of onset and order of appearance of clinical features into infantile, late-infantile, juvenile, adult, and Northern epilepsy (also known as progressive epilepsy with mental retardation [EPMR]). There is however genetic and allelic heterogeneity; a proposed new nomenclature and classification system has been developed to take into account both the responsible gene and the age at disease onset; for example, CLN1 disease, infantile onset and CLN1 disease, juvenile onset are both caused by mutations in PPT1 but with differing age of onset. The most prevalent NCLs are CLN3 disease, classic juvenile and CLN2 disease, classic late infantile (although prevalence varies by ethnicity and country of family origin): CLN2 disease, classic late infantile. The first symptoms typically appear between age two and four years, usually starting with epilepsy, followed by regression of developmental milestones, myoclonic ataxia, and pyramidal signs. Visual impairment typically appears at age four to six years and rapidly progresses to light /dark awareness only. Life expectancy ranges from age six years to early teenage. CLN3 disease, classic juvenile. Onset is usually between ages four and ten years. Rapidly progressing visual loss resulting in severe visual impairment within one to two years is often the first clinical sign. Epilepsy with generalized tonic-clonic seizures and/or complex-partial seizures typically appears around age ten years. Life expectancy ranges from the late teens to the 30s. Other forms of NCL may present with behavior changes, epilepsy, visual impairment, or slowing of developmental progress and then loss of skills. The course may be extremely variable. Some genotype-phenotype information is available.
Microphthalmia syndromic 6
MedGen UID:
355268
Concept ID:
C1864689
Disease or Syndrome
Microphthalmia, anophthalmia, and coloboma comprise the MAC spectrum of ocular malformations. Microphthalmia refers to a globe with a total axial length that is at least two standard deviations below the mean for age. Anophthalmia refers to complete absence of the globe in the presence of ocular adnexa (eyelids, conjunctiva, and lacrimal apparatus). Coloboma refers to the ocular malformations that result from failure of closure of the optic fissure. Chorioretinal coloboma refers to coloboma of the retina and choroid. Iris coloboma causes the iris to appear keyhole-shaped. Microphthalmia, anophthalmia, and coloboma may be unilateral or bilateral; when bilateral they may occur in any combination.
Microphthalmia syndromic 5
MedGen UID:
350491
Concept ID:
C1864690
Disease or Syndrome
Pyridoxal 5'-phosphate-dependent epilepsy
MedGen UID:
350498
Concept ID:
C1864723
Disease or Syndrome
Pyridoxal 5'-phosphate-dependent epilepsy is a condition that involves seizures beginning soon after birth or, in some cases, before birth. The seizures typically involve irregular involuntary muscle contractions (myoclonus), abnormal eye movements, and convulsions. Most babies with this condition are born prematurely and may have a temporary, potentially toxic, increase in lactic acid in the blood (lactic acidosis). Additionally, some infants have a slow heart rate and a lack of oxygen during delivery (fetal distress). Anticonvulsant drugs, which are usually given to control seizures, are ineffective in people with pyridoxal 5'-phosphate-dependent epilepsy. Instead, individuals with this type of epilepsy are medically treated with large daily doses of pyridoxal 5'-phosphate (a form of vitamin B6). If left untreated, people with this condition can develop severe brain dysfunction (encephalopathy), which can lead to death. Even though seizures can be controlled with pyridoxal 5'-phosphate, neurological problems such as developmental delay and learning disorders may still occur.
Combined oxidative phosphorylation deficiency 3
MedGen UID:
355842
Concept ID:
C1864840
Disease or Syndrome
Koolen-de Vries syndrome
MedGen UID:
355853
Concept ID:
C1864871
Disease or Syndrome
The KANSL1-related intellectual disability syndrome is characterized by developmental delay/intellectual disability, neonatal/childhood hypotonia, dysmorphisms, congenital malformations, and behavioral features. Global psychomotor developmental delay is noted in all individuals from an early age. The majority of individuals with the KANSL1-related intellectual disability syndrome function in the mild to moderate range of intellectual disability. Other findings include epilepsy (55%), congenital heart defects (39%), renal and urologic anomalies (37%), and cryptorchidism (71% of males). Behavior in most is described as friendly, amiable, and cooperative.
Cortical dysplasia-focal epilepsy syndrome
MedGen UID:
355859
Concept ID:
C1864887
Disease or Syndrome
Glutamine deficiency, congenital
MedGen UID:
400638
Concept ID:
C1864910
Disease or Syndrome
Congenital glutamine deficiency is a severe autosomal recessive disorder characterized by onset at birth of encephalopathy, lack of normal development, seizures, and hypotonia associated with variable brain abnormalities. Three patients have been reported (summary by Haberle et al., 2011).
Deficiency of 2-methylbutyryl-CoA dehydrogenase
MedGen UID:
355324
Concept ID:
C1864912
Disease or Syndrome
2-Methylbutyryl-CoA dehydrogenase (MBD) deficiency is an autosomal recessive metabolic disorder of impaired isoleucine degradation. It is most often ascertained via newborn screening and is usually clinically asymptomatic, although some patients have been reported to have delayed development and neurologic signs. Therefore, the clinical relevance of the deficiency is unclear (Sass et al.., 2008).
Ceroid lipofuscinosis, neuronal, 8, northern epilepsy variant
MedGen UID:
355328
Concept ID:
C1864923
Disease or Syndrome
The neuronal ceroid lipofuscinoses (NCL; CLN) are a clinically and genetically heterogeneous group of neurodegenerative disorders characterized by the intracellular accumulation of autofluorescent lipopigment storage material in different patterns ultrastructurally. The lipopigment patterns observed most often in CLN8 comprise mixed combinations of 'granular,' 'curvilinear,' and 'fingerprint' profiles (Mole et al., 2005). For a general phenotypic description and a discussion of genetic heterogeneity of CLN, see CLN1 (256730).
Familial hemiplegic migraine type 3
MedGen UID:
400655
Concept ID:
C1864987
Disease or Syndrome
Familial hemiplegic migraine (FHM) falls within the category of migraine with aura. In migraine with aura (including familial hemiplegic migraine) the neurologic symptoms of aura are unequivocally localizable to the cerebral cortex or brain stem and include visual disturbance (most common), sensory loss (e.g., numbness or paresthesias of the face or an extremity), and dysphasia (difficulty with speech); FHM must include motor involvement, i.e., hemiparesis (weakness of an extremity). Hemiparesis occurs with at least one other symptom during FHM aura. Neurologic deficits with FHM attacks can be prolonged for hours to days and may outlast the associated migrainous headache. FHM is often earlier in onset than typical migraine, frequently beginning in the first or second decade; the frequency of attacks tends to decrease with age. Approximately 40%-50% of families with FHM1 have cerebellar signs ranging from nystagmus to progressive, usually late-onset mild ataxia. Cerebral infarction and death have rarely been associated with hemiplegic migraine.
Skeletal dysplasia and progressive central nervous system degeneration, lethal
MedGen UID:
400685
Concept ID:
C1865117
Disease or Syndrome
Muscular dystrophy, congenital, megaconial type
MedGen UID:
355943
Concept ID:
C1865233
Disease or Syndrome
Congenital muscular dystrophy (CMD) is a clinically and genetically heterogeneous group of inherited muscle disorders. Muscle weakness typically presents from birth to early infancy. Affected infants typically appear "floppy" with low muscle tone and poor spontaneous movements. Affected children may present with delay or arrest of gross motor development together with joint and/or spinal rigidity. Muscle weakness may improve, worsen, or stabilize in the short term; however, with time progressive weakness and joint contractures, spinal deformities, and respiratory compromise may affect quality of life and life span. The main CMD subtypes, grouped by involved protein function and gene in which causative mutations occur, are laminin alpha-2 (merosin) deficiency (MDC1A), collagen VI-deficient CMD, the dystroglycanopathies (caused by mutations in POMT1, POMT2, FKTN, FKRP, LARGE, POMGNT1, and ISPD), SEPN1-related CMD (previously known as rigid spine syndrome, RSMD1) and LMNA-related CMD (L-CMD). Several less known CMD subtypes have been reported in a limited number of individuals. Cognitive impairment ranging from intellectual disability to mild cognitive delay, structural brain and/or eye abnormalities, and seizures are found almost exclusively in the dystroglycanopathies while white matter abnormalities without major cognitive involvement tend to be seen in the laminin alpha-2-deficient subtype.
Megalencephaly cutis marmorata telangiectatica congenita
MedGen UID:
355421
Concept ID:
C1865285
Congenital Abnormality
Megalencephaly-capillary malformation-polymicrogyria syndrome (MCAP) is characterized by a spectrum of anomalies including primary megalencephaly, prenatal overgrowth, brain and body asymmetry, cutaneous vascular malformations, digital anomalies consisting of syndactyly with or without postaxial polydactyly, connective tissue dysplasia involving the skin, subcutaneous tissue, and joints, and cortical brain malformations, most distinctively polymicrogyria (summary by Mirzaa et al., 2012). This disorder is also known as the macrocephaly-capillary malformation (MCM) syndrome (Conway et al., 2007). Mirzaa et al. (2012) suggested use of the term MCAP rather than MCM to reflect the very large brain size, rather than simply large head size, that characterizes this syndrome, and the importance and high frequency of perisylvian polymicrogyria.
Familial hemiplegic migraine type 2
MedGen UID:
355962
Concept ID:
C1865322
Disease or Syndrome
Familial hemiplegic migraine (FHM) falls within the category of migraine with aura. In migraine with aura (including familial hemiplegic migraine) the neurologic symptoms of aura are unequivocally localizable to the cerebral cortex or brain stem and include visual disturbance (most common), sensory loss (e.g., numbness or paresthesias of the face or an extremity), and dysphasia (difficulty with speech); FHM must include motor involvement, i.e., hemiparesis (weakness of an extremity). Hemiparesis occurs with at least one other symptom during FHM aura. Neurologic deficits with FHM attacks can be prolonged for hours to days and may outlast the associated migrainous headache. FHM is often earlier in onset than typical migraine, frequently beginning in the first or second decade; the frequency of attacks tends to decrease with age. Approximately 40%-50% of families with FHM1 have cerebellar signs ranging from nystagmus to progressive, usually late-onset mild ataxia. Cerebral infarction and death have rarely been associated with hemiplegic migraine.
Ethylmalonic encephalopathy
MedGen UID:
355966
Concept ID:
C1865349
Disease or Syndrome
Ethylmalonic encephalopathy is an autosomal recessive severe metabolic disorder of infancy affecting the brain, gastrointestinal tract, and peripheral vessels. The disorder is characterized by neurodevelopmental delay and regression, prominent pyramidal and extrapyramidal signs, recurrent petechiae, orthostatic acrocyanosis, and chronic diarrhea. Brain MRI shows necrotic lesions in deep gray matter structures. Death usually occurs in the first decade of life (summary by Drousiotou et al., 2011).
Desmosterolosis
MedGen UID:
400801
Concept ID:
C1865596
Disease or Syndrome
Desmosterolosis is a rare autosomal recessive disorder characterized by multiple congenital anomalies and elevated levels of the cholesterol precursor desmosterol in plasma, tissue, and cultured cells (summary by Waterham et al., 2001).
Gracile bone dysplasia
MedGen UID:
356331
Concept ID:
C1865639
Disease or Syndrome
Gracile bone dysplasia is a perinatally lethal condition characterized by gracile bones with thin diaphyses, premature closure of basal cranial sutures, and microphthalmia (summary by Unger et al., 2013).
Plantar lipomatosis, unusual facies, and developmental delay
MedGen UID:
356049
Concept ID:
C1865644
Disease or Syndrome
Pierpont syndrome is a multiple congenital anomaly syndrome associated with learning disability. Key features include distinctive facial characteristics, especially when smiling, plantar fat pads, and other limb anomalies (summary by Burkitt Wright et al., 2011).
Infantile convulsions and paroxysmal choreoathetosis, familial
MedGen UID:
356123
Concept ID:
C1865926
Disease or Syndrome
Benign familial infantile convulsions (BFIC; see 601764) is an autosomal dominant disorder characterized by afebrile seizures occurring between 3 and 12 months of age. Paroxysmal choreoathetosis is a disorder of involuntary movements characterized by attacks that occur spontaneously or are induced by a variety of stimuli. The ICCA syndrome shares overlapping clinical features with benign familial infantile seizures-2 (BFIS2; 605751) and episodic kinesigenic dyskinesia-1 (EKD1; 128200), which are allelic disorders. See also rolandic epilepsy with paroxysmal exercise-induced dystonia and writer's cramp (608105), which maps to 16p.
Hypomagnesemia 1, intestinal
MedGen UID:
355596
Concept ID:
C1865974
Disease or Syndrome
Familial hypomagnesemia with secondary hypocalcemia is a rare autosomal recessive disorder characterized by very low serum magnesium levels. Hypocalcemia is a secondary consequence of parathyroid failure and parathyroid hormone resistance as a result of severe magnesium deficiency. The disease typically manifests during the first months of life with generalized convulsions or signs of increased neuromuscular excitability, such as muscle spasms or tetany. Untreated, the disease may be fatal or lead to severe neurologic damage. Treatment includes immediate administration of magnesium, usually intravenously, followed by life-long high-dose oral magnesium (reviewed by Knoers, 2009). Genetic Heterogeneity of Hypomagnesemia A form of hypomagnesemia due to kidney defects and high urinary magnesium excretion associated with hypocalciuria (HOMG2; 154020) is caused by mutation in the FXYD2 gene (601814). Renal hypomagnesemia-3 (HOMG3; 248250), associated with hypercalciuria and nephrocalcinosis, is caused by mutation in the CLDN16 gene (603959). Renal hypomagnesemia-4 (HOMG4; 611718), which is normocalciuric, is caused by mutation in the EGF gene (131530). Renal hypomagnesemia-5 (HOMG5; 248190), associated with hypercalciuria, nephrocalcinosis, and severe ocular involvement, is caused by mutation in the CLDN19 gene (610036). Renal hypomagnesemia-6 (HOMG6; 613882) is caused by mutation in the CNNM2 gene (607803). Patients with Gitelman syndrome (263800) and Bartter syndrome (see 241200) also show hypomagnesemia, and steatorrhea and severe chronic diarrhea states, such as Crohn disease (see 226600) and Whipple disease, that can result in severe hypomagnesemia.
Phosphoglycerate dehydrogenase deficiency
MedGen UID:
400935
Concept ID:
C1866174
Disease or Syndrome
Phosphoglycerate dehydrogenase deficiency is an autosomal recessive inborn error of L-serine biosynthesis that is characterized by congenital microcephaly, psychomotor retardation, and seizures (summary by Jaeken et al., 1996).
Ceroid lipofuscinosis neuronal 6
MedGen UID:
356494
Concept ID:
C1866282
Disease or Syndrome
The neuronal ceroid-lipofuscinoses (NCLs) are a group of inherited, neurodegenerative, lysosomal storage disorders characterized by progressive intellectual and motor deterioration, seizures, and early death. Visual gvhmloss is a feature of most forms. Clinical phenotypes have been characterized traditionally according to the age of onset and order of appearance of clinical features into infantile, late-infantile, juvenile, adult, and Northern epilepsy (also known as progressive epilepsy with mental retardation [EPMR]). There is however genetic and allelic heterogeneity; a proposed new nomenclature and classification system has been developed to take into account both the responsible gene and the age at disease onset; for example, CLN1 disease, infantile onset and CLN1 disease, juvenile onset are both caused by mutations in PPT1 but with differing age of onset. The most prevalent NCLs are CLN3 disease, classic juvenile and CLN2 disease, classic late infantile (although prevalence varies by ethnicity and country of family origin): CLN2 disease, classic late infantile. The first symptoms typically appear between age two and four years, usually starting with epilepsy, followed by regression of developmental milestones, myoclonic ataxia, and pyramidal signs. Visual impairment typically appears at age four to six years and rapidly progresses to light /dark awareness only. Life expectancy ranges from age six years to early teenage. CLN3 disease, classic juvenile. Onset is usually between ages four and ten years. Rapidly progressing visual loss resulting in severe visual impairment within one to two years is often the first clinical sign. Epilepsy with generalized tonic-clonic seizures and/or complex-partial seizures typically appears around age ten years. Life expectancy ranges from the late teens to the 30s. Other forms of NCL may present with behavior changes, epilepsy, visual impairment, or slowing of developmental progress and then loss of skills. The course may be extremely variable. Some genotype-phenotype information is available.
Bartter syndrome antenatal type 1
MedGen UID:
355727
Concept ID:
C1866495
Disease or Syndrome
Bartter syndrome is a group of very similar kidney disorders that cause an imbalance of potassium, sodium, chloride, and related molecules in the body. In some cases, Bartter syndrome becomes apparent before birth. The disorder can cause polyhydramnios, which is an increased volume of fluid surrounding the fetus (amniotic fluid). Polyhydramnios increases the risk of premature birth. Beginning in infancy, affected individuals often fail to grow and gain weight at the expected rate (failure to thrive). They lose excess amounts of salt (sodium chloride) in their urine, which leads to dehydration, constipation, and increased urine production (polyuria). In addition, large amounts of calcium are lost through the urine (hypercalciuria), which can cause weakening of the bones (osteopenia). Some of the calcium is deposited in the kidneys as they are concentrating urine, leading to hardening of the kidney tissue (nephrocalcinosis). Bartter syndrome is also characterized by low levels of potassium in the blood (hypokalemia), which can result in muscle weakness, cramping, and fatigue. Rarely, affected children develop hearing loss caused by abnormalities in the inner ear (sensorineural deafness). Two major forms of Bartter syndrome are distinguished by their age of onset and severity. One form begins before birth (antenatal) and is often life-threatening. The other form, often called the classical form, begins in early childhood and tends to be less severe. Once the genetic causes of Bartter syndrome were identified, researchers also split the disorder into different types based on the genes involved. Types I, II, and IV have the features of antenatal Bartter syndrome. Because type IV is also associated with hearing loss, it is sometimes called antenatal Bartter syndrome with sensorineural deafness. Type III usually has the features of classical Bartter syndrome.
Splenogonadal fusion limb defects micrognatia
MedGen UID:
401073
Concept ID:
C1866745
Disease or Syndrome
Splenogonadal fusion (SGF) is a rare congenital anomaly of abnormal fusion between the spleen and the gonad or the remnants of the mesonephros. In 'continuous SGF,' there is a cord-like connection between the 2 organs, whereas in 'discontinuous SGF,' there is fusion of accessory splenic tissue and the gonad without a distinct structural connection to the spleen itself. Forty-eight percent of individuals with continuous SGF have additional malformations, compared to 9% of those with discontinuous SGF (McPherson et al., 2003).
Spastic paraplegia epilepsy mental retardation
MedGen UID:
356631
Concept ID:
C1866854
Disease or Syndrome
Scleroderma, familial progressive
MedGen UID:
356661
Concept ID:
C1866983
Disease or Syndrome
Systemic sclerosis is a clinically heterogeneous connective tissue disorder characterized by immune activation, vascular damage, and fibrosis of the skin and major internal organs. Clinical and experimental data suggest that the disorder is multifactorial, involving both genetic and environmental factors (Fonseca et al., 2007). Gabrielli et al. (2009) provided a detailed review of scleroderma, including clinical manifestations and pathophysiology. See also Reynolds syndrome (613471), which shares some clinical features with scleroderma and CREST syndrome.
Scholte syndrome
MedGen UID:
401129
Concept ID:
C1866985
Disease or Syndrome
Pterygia, mental retardation and distinctive craniofacial features
MedGen UID:
357988
Concept ID:
C1867443
Disease or Syndrome
Familial porencephaly
MedGen UID:
401353
Concept ID:
C1867983
Congenital Abnormality
The spectrum of COL4A1-related disorders includes: small-vessel brain disease of varying severity variably associated with porencephaly, cerebral aneurysms, eye defects (retinal arterial tortuosity, Axenfeld-Rieger anomaly, cataract) and systemic findings (kidney involvement, muscle cramps, Raynaud phenomenon, and cardiac arrhythmia). On imaging studies, small-vessel brain disease is manifest as diffuse periventricular leukoencephalopathy, lacunar infarcts, microhemorrhage, dilated perivascular spaces, and deep intracerebral hemorrhages. Clinically, small-vessel brain disease manifests as infantile hemiparesis, seizures, single or recurrent hemorrhagic stroke, ischemic stroke, and isolated migraine with aura. Porencephaly (fluid-filled cavities in the brain detected by CT or MRI) is typically manifest as infantile hemiparesis, seizures, and intellectual disability; however, on occasion it can be an incidental finding. Hereditary angiopathy with nephropathy, aneurysms, and muscle cramps (HANAC) syndrome usually associates asymptomatic small-vessel brain disease, cerebral large vessel involvement (i.e., aneurysms), and systemic findings involving the kidney, muscle, and small vessels of the eye.
ZELLWEGER SYNDROME 2
MedGen UID:
356968
Concept ID:
C1868416
Disease or Syndrome
Patterson pseudoleprechaunism syndrome
MedGen UID:
358350
Concept ID:
C1868546
Disease or Syndrome
Parietal foramina
MedGen UID:
358250
Concept ID:
C1868598
Disease or Syndrome
Enlarged parietal foramina are characteristic symmetric, paired radiolucencies of the parietal bones, located close to the intersection of the sagittal and lambdoid sutures, caused by deficient ossification around the parietal notch, which is normally obliterated by the fifth month of fetal development. Enlarged parietal foramina are usually asymptomatic. Meningeal, cortical, and vascular malformations of the posterior fossa occasionally accompany the bone defects and may predispose to epilepsy. In a minority of individuals, headaches, vomiting, or intense local pain are sometimes associated with the defects, especially on application of mild pressure to the unprotected cerebral cortex.
Thanatophoric dysplasia type 1
MedGen UID:
358383
Concept ID:
C1868678
Congenital Abnormality
Thanatophoric dysplasia (TD) is a short-limb dwarfism syndrome that is usually lethal in the perinatal period. TD is divided into type I, characterized by micromelia with bowed femurs and, uncommonly, the presence of cloverleaf skull deformity (Kleeblattschädel) of varying severity; and type II, characterized by micromelia with straight femurs and uniform presence of moderate-to-severe cloverleaf skull deformity. Other features common to type I and type II include: short ribs, narrow thorax, macrocephaly, distinctive facial features, brachydactyly, hypotonia, and redundant skin folds along the limbs. Most affected infants die of respiratory insufficiency shortly after birth. Rare long-term survivors have been reported.
Griscelli syndrome type 2
MedGen UID:
357030
Concept ID:
C1868679
Disease or Syndrome
Griscelli syndrome is an inherited condition characterized by unusually light (hypopigmented) skin and light silvery-gray hair starting in infancy. Researchers have identified three types of this disorder, which are distinguished by their genetic cause and pattern of signs and symptoms. Griscelli syndrome type 1 involves severe problems with brain function in addition to the distinctive skin and hair coloring. Affected individuals typically have delayed development, intellectual disability, seizures, weak muscle tone (hypotonia), and eye and vision abnormalities. Another condition called Elejalde disease has many of the same signs and symptoms, and some researchers have proposed that Griscelli syndrome type 1 and Elejalde disease are actually the same disorder. People with Griscelli syndrome type 2 have immune system abnormalities in addition to having hypopigmented skin and hair. Affected individuals are prone to recurrent infections. They also develop an immune condition called hemophagocytic lymphohistiocytosis (HLH), in which the immune system produces too many activated immune cells called T-lymphocytes and macrophages (histiocytes). Overactivity of these cells can damage organs and tissues throughout the body, causing life-threatening complications if the condition is untreated. People with Griscelli syndrome type 2 do not have the neurological abnormalities of type 1. Unusually light skin and hair coloring are the only features of Griscelli syndrome type 3. People with this form of the disorder do not have neurological abnormalities or immune system problems.
Dystonia 10
MedGen UID:
358268
Concept ID:
C1868682
Disease or Syndrome
Familial paroxysmal kinesigenic dyskinesia (referred to as familial PKD in this entry) is characterized by unilateral or bilateral involuntary movements precipitated by other sudden movements such as standing up from a sitting position, being startled, or changes in velocity; attacks include combinations of dystonia, choreoathetosis, and ballism, are sometimes preceded by an aura, and do not involve loss of consciousness. Attacks can be as frequent as 100 per day to as few as one per month. Attacks are usually a few seconds to five minutes in duration but can last several hours. Age of onset, severity and combinations of symptoms vary. Age of onset, typically in childhood and adolescence, ranges from four months to 57 years. The phenotype of PKD can include benign familial infantile epilepsy (BFIE), infantile convulsions and choreoathetosis (ICCA), hemiplegic migraine, migraine with and without aura, and episodic ataxia. Familial PKD is predominantly seen in males.
Addison's disease
MedGen UID:
357032
Concept ID:
C1868690
Disease or Syndrome
Autoimmune Addison disease affects the function of the adrenal glands, which are small hormone-producing glands located on top of each kidney. It is classified as an autoimmune disorder because it results from a malfunctioning immune system that attacks the adrenal glands. As a result, the production of several hormones is disrupted, which affects many body systems. The signs and symptoms of autoimmune Addison disease can begin at any time, although they most commonly begin between ages 30 and 50. Common features of this condition include extreme tiredness (fatigue), nausea, decreased appetite, and weight loss. In addition, many affected individuals have low blood pressure (hypotension), which can lead to dizziness when standing up quickly; muscle cramps; and a craving for salty foods. A characteristic feature of autoimmune Addison disease is abnormally dark areas of skin (hyperpigmentation), especially in regions that experience a lot of friction, such as the armpits, elbows, knuckles, and palm creases. The lips and the inside lining of the mouth can also be unusually dark. Because of an imbalance of hormones involved in development of sexual characteristics, women with this condition may lose their underarm and pubic hair. Other signs and symptoms of autoimmune Addison disease include low levels of sugar (hypoglycemia) and sodium (hyponatremia) and high levels of potassium (hyperkalemia) in the blood. Affected individuals may also have a shortage of red blood cells (anemia) and an increase in the number of white blood cells (lymphocytosis), particularly those known as eosinophils (eosinophilia). Autoimmune Addison disease can lead to a life-threatening adrenal crisis, characterized by vomiting, abdominal pain, back or leg cramps, and severe hypotension leading to shock. The adrenal crisis is often triggered by a stressor, such as surgery, trauma, or infection. Individuals with autoimmune Addison disease or their family members often have another autoimmune disorder, most commonly autoimmune thyroid disease or type 1 diabetes.
Ceroid lipofuscinosis, neuronal, 2
MedGen UID:
406281
Concept ID:
C1876161
Disease or Syndrome
The neuronal ceroid-lipofuscinoses (NCLs) are a group of inherited, neurodegenerative, lysosomal storage disorders characterized by progressive intellectual and motor deterioration, seizures, and early death. Visual gvhmloss is a feature of most forms. Clinical phenotypes have been characterized traditionally according to the age of onset and order of appearance of clinical features into infantile, late-infantile, juvenile, adult, and Northern epilepsy (also known as progressive epilepsy with mental retardation [EPMR]). There is however genetic and allelic heterogeneity; a proposed new nomenclature and classification system has been developed to take into account both the responsible gene and the age at disease onset; for example, CLN1 disease, infantile onset and CLN1 disease, juvenile onset are both caused by mutations in PPT1 but with differing age of onset. The most prevalent NCLs are CLN3 disease, classic juvenile and CLN2 disease, classic late infantile (although prevalence varies by ethnicity and country of family origin): CLN2 disease, classic late infantile. The first symptoms typically appear between age two and four years, usually starting with epilepsy, followed by regression of developmental milestones, myoclonic ataxia, and pyramidal signs. Visual impairment typically appears at age four to six years and rapidly progresses to light /dark awareness only. Life expectancy ranges from age six years to early teenage. CLN3 disease, classic juvenile. Onset is usually between ages four and ten years. Rapidly progressing visual loss resulting in severe visual impairment within one to two years is often the first clinical sign. Epilepsy with generalized tonic-clonic seizures and/or complex-partial seizures typically appears around age ten years. Life expectancy ranges from the late teens to the 30s. Other forms of NCL may present with behavior changes, epilepsy, visual impairment, or slowing of developmental progress and then loss of skills. The course may be extremely variable. Some genotype-phenotype information is available.
KENNY-CAFFEY SYNDROME, TYPE 2
MedGen UID:
406287
Concept ID:
C1876180
Congenital Abnormality
4p partial monosomy syndrome
MedGen UID:
408255
Concept ID:
C1956097
Disease or Syndrome
Wolf-Hirschhorn syndrome (WHS) is characterized by typical craniofacial features in infancy consisting of ‘Greek warrior helmet’ appearance of the nose (wide bridge of the nose continuing to the forehead), microcephaly, high anterior hairline with prominent glabella, widely spaced eyes, epicanthus, highly arched eyebrows, short philtrum, downturned corners of the mouth, micrognathia, and poorly formed ears with pits/tags. All affected individuals have prenatal-onset growth deficiency followed by postnatal growth retardation and hypotonia with muscle underdevelopment. Developmental delay/intellectual disability of variable degree is present in all. Seizures occur in 90% to 100% of children with WHS. Other findings include skeletal anomalies (60%-70%), congenital heart defects (~50%), hearing loss (mostly conductive) (>40%), urinary tract malformations (25%), and structural brain abnormalities (33%).
Mevalonic aciduria
MedGen UID:
368373
Concept ID:
C1959626
Disease or Syndrome
Mevalonic aciduria, the first recognized defect in the biosynthesis of cholesterol and isoprenoids, is a consequence of a deficiency of mevalonate kinase (ATP:mevalonate 5-phosphotransferase; EC 2.7.1.36). Mevalonic acid accumulates because of failure of conversion to 5-phosphomevalonic acid, which is catalyzed by mevalonate kinase. Mevalonic acid is synthesized from 3-hydroxy-3-methylglutaryl-CoA, a reaction catalyzed by HMG-CoA reductase (142910). Mevalonic aciduria is characterized by dysmorphology, psychomotor retardation, progressive cerebellar ataxia, and recurrent febrile crises, usually manifesting in early infancy, accompanied by hepatosplenomegaly, lymphadenopathy, arthralgia, and skin rash. The febrile crises are similar to those observed in hyperimmunoglobulinemia D and to periodic fever syndrome (HIDS; 260920), which is also caused by mutation in the MVK gene (summary by Prietsch et al, 2003).
Spinocerebellar ataxia 10
MedGen UID:
369786
Concept ID:
C1963674
Disease or Syndrome
SCA10 is characterized by slowly progressive cerebellar ataxia that usually starts as poor balance and unsteady gait, followed by upper-limb ataxia, scanning dysarthria, and dysphagia. The disease is exclusively found in Latin American populations, particularly those with Amerindian admixture. Abnormal tracking eye movements are common. Recurrent seizures after the onset of gait ataxia have been reported with variable frequencies among different families. Some individuals have cognitive dysfunction, behavioral disturbances, mood disorders, mild pyramidal signs, and peripheral neuropathy. Onset ranges from age 12 to 48 years.
Mental retardation, X-linked, syndromic 13
MedGen UID:
368466
Concept ID:
C1968550
Disease or Syndrome
The MECP2 gene is mutated in Rett syndrome (RTT; 312750), a severe neurodevelopmental disorder that almost always occurs in females. Males with non-RTT mutations in the MECP2 gene can demonstrate a wide variety of phenotypes, including X-linked mental retardation with spasticity and other variable features, described here, and Lubs X-linked mental retardation syndrome (MRXSL; 300260). Males with RTT-associated MECP2 mutations have neonatal severe encephalopathy that is usually lethal (300673) (Moog et al., 2003; Villard, 2007).
Encephalopathy, neonatal severe, due to MECP2 mutations
MedGen UID:
409616
Concept ID:
C1968556
Disease or Syndrome
MECP2-related disorders in females include classic Rett syndrome, variant Rett syndrome, and mild learning disabilities. A pathogenic MECP2 variant in a male is presumed to most often be lethal; phenotypes in rare surviving males are primarily severe neonatal encephalopathy and manic-depressive psychosis, pyramidal signs, Parkinsonian, and macro-orchidism (PPM-X syndrome). Classic Rett syndrome, a progressive neurodevelopmental disorder primarily affecting girls, is characterized by apparently normal psychomotor development during the first six to 18 months of life, followed by a short period of developmental stagnation, then rapid regression in language and motor skills, followed by long-term stability. During the phase of rapid regression, repetitive, stereotypic hand movements replace purposeful hand use. Additional findings include fits of screaming and inconsolable crying, autistic features, panic-like attacks, bruxism, episodic apnea and/or hyperpnea, gait ataxia and apraxia, tremors, seizures, and acquired microcephaly. Atypical Rett syndrome is observed increasingly as MECP2 variants are identified in individuals previously diagnosed with: clinically suspected but molecularly unconfirmed Angelman syndrome; intellectual disability with spasticity or tremor; mild learning disability; or (rarely) autism. Severe neonatal encephalopathy resulting in death before age two years is the most common phenotype observed in affected males.
Lissencephaly 3
MedGen UID:
369910
Concept ID:
C1969029
Disease or Syndrome
Pontocerebellar hypoplasia type 6
MedGen UID:
370596
Concept ID:
C1969084
Disease or Syndrome
Pontocerebellar hypoplasia (PCH) is a heterogeneous group of disorders characterized by an abnormally small cerebellum and brainstem and associated with severe developmental delay (Edvardson et al., 2007). For a phenotypic description and a discussion of genetic heterogeneity of PCH, see PCH1 (607596).
Autism 8
MedGen UID:
409897
Concept ID:
C1969710
Finding
Autism, the prototypic pervasive developmental disorder (PDD), is usually apparent by 3 years of age. It is characterized by a triad of limited or absent verbal communication, a lack of reciprocal social interaction or responsiveness, and restricted, stereotypical, and ritualized patterns of interests and behavior (Bailey et al., 1996; Risch et al., 1999). 'Autism spectrum disorder,' sometimes referred to as ASD, is a broader phenotype encompassing the less severe disorders Asperger syndrome (see ASPG1; 608638) and pervasive developmental disorder, not otherwise specified (PDD-NOS). 'Broad autism phenotype' includes individuals with some symptoms of autism, but who do not meet the full criteria for autism or other disorders. Mental retardation coexists in approximately two-thirds of individuals with ASD, except for Asperger syndrome, in which mental retardation is conspicuously absent (Jones et al., 2008). Genetic studies in autism often include family members with these less stringent diagnoses (Schellenberg et al., 2006). For a discussion of genetic heterogeneity of autism, see 209850.
Aplasia Cutis Congenita, Congenital Heart Defect, And Frontonasal Cysts
MedGen UID:
370187
Concept ID:
C1970140
Disease or Syndrome
Paroxysmal nonkinesigenic dyskinesia 2
MedGen UID:
370188
Concept ID:
C1970149
Disease or Syndrome
Familial paroxysmal nonkinesigenic dyskinesia is a disorder of the nervous system that causes periods of involuntary movement. Paroxysmal indicates that the abnormal movements come and go over time. Nonkinesigenic means that episodes are not triggered by sudden movement. Dyskinesia broadly refers to involuntary movement of the body. People with familial paroxysmal nonkinesigenic dyskinesia experience episodes of abnormal movement that develop without a known cause or are brought on by alcohol, caffeine, stress, fatigue, menses, or excitement. Episodes are not induced by exercise or sudden movement and do not occur during sleep. An episode is characterized by irregular, jerking or shaking movements that range from mild to severe. In this disorder, the dyskinesias can include slow, prolonged contraction of muscles (dystonia); small, fast, "dance-like" motions (chorea); writhing movements of the limbs (athetosis); and, rarely, flailing movements of the limbs (ballismus). Dyskinesias also affect muscles in the trunk and face. The type of abnormal movement varies among affected individuals, even among members of the same family. Individuals with familial paroxysmal nonkinesigenic dyskinesia do not lose consciousness during an episode. Most people do not experience any other neurological symptoms between episodes. Individuals with familial paroxysmal nonkinesigenic dyskinesia usually begin to show signs and symptoms of the disorder during childhood or their early teens. Episodes typically last 1-4 hours, and the frequency of episodes ranges from several per day to one per year. In some affected individuals, episodes occur less often with age.
Mental retardation, autosomal recessive 6
MedGen UID:
370848
Concept ID:
C1970198
Disease or Syndrome
Mental retardation, autosomal recessive 5
MedGen UID:
370849
Concept ID:
C1970199
Disease or Syndrome
Phosphoserine aminotransferase deficiency
MedGen UID:
410026
Concept ID:
C1970253
Disease or Syndrome
Deficiency of phosphoserine aminotransferase (PSAT; EC 2.6.1.52) is characterized biochemically by low plasma and cerebrospinal fluid (CSF) concentrations of serine and glycine and clinically by intractable seizures, acquired microcephaly, hypertonia, and psychomotor retardation. Outcome is poor once the individual becomes symptomatic, but treatment with serine and glycine supplementation from birth can lead to a normal outcome (Hart et al., 2007).
Pitt-Hopkins syndrome
MedGen UID:
370910
Concept ID:
C1970431
Disease or Syndrome
Pitt-Hopkins syndrome (PTHS) is characterized by distinctive facial features which become more apparent with age (100%), developmental delay/intellectual disability (100%), and episodic hyperventilation and/or breath-holding while awake (55%-60%). Global developmental delays are significant and intellectual disability is moderate to severe: mean age of walking is four to six years; most affected individuals are nonverbal. Other common findings are behavioral issues, hand stereotypic movements, seizures (40%-50%), constipation, and severe myopia.
Potocki-Lupski syndrome
MedGen UID:
410082
Concept ID:
C1970482
Disease or Syndrome
Potocki-Lupski syndrome is a developmental disorder characterized by hypotonia, failure to thrive, mental retardation, pervasive developmental disorders, and congenital anomalies. All reported cases have occurred sporadically without bias in the parental origin of rearrangements. Most duplications are 3.7 Mb in size and only identifiable by array comparative genomic hybridization (CGH) analysis. Approximately 60% of PTLS patients harbor a microduplication of chromosome 17p11.2 reciprocal to the common recurrent 3.7-Mb microdeletion in SMS (summary by Shchelochkov et al., 2010).
Phosphoglycerate kinase 1 deficiency
MedGen UID:
410166
Concept ID:
C1970848
Disease or Syndrome
Phosphoglycerate kinase-1 deficiency is an X-linked recessive condition with a highly variable clinical phenotype that includes hemolytic anemia, myopathy, and neurologic involvement. Patients can express 1, 2, or all 3 of these manifestations (Shirakawa et al., 2006).
Combined saposin deficiency
MedGen UID:
382151
Concept ID:
C2673635
Disease or Syndrome
Combined oxidative phosphorylation deficiency 5
MedGen UID:
435972
Concept ID:
C2673642
Disease or Syndrome
Hypomagnesemia 4, renal
MedGen UID:
388692
Concept ID:
C2673648
Disease or Syndrome
Hypomyelination and Congenital Cataract
MedGen UID:
382379
Concept ID:
C2674508
Disease or Syndrome
Hypomyelination and congenital cataract (HCC) is usually characterized by bilateral congenital cataracts and normal psychomotor development in the first year of life, followed by slowly progressive neurologic impairment manifest as ataxia, spasticity (brisk tendon reflexes and bilateral extensor plantar responses), and mild to moderate cognitive impairment. Dysarthria and truncal hypotonia are observed. Cerebellar signs (truncal titubation and intention tremor) and peripheral neuropathy (muscle weakness and wasting of the legs) are present in the majority of affected individuals. Seizures can occur. In a few cases cataracts may be absent.
Chromosome 10q26 deletion syndrome
MedGen UID:
436306
Concept ID:
C2674937
Disease or Syndrome
Episodic ataxia, type 6
MedGen UID:
390739
Concept ID:
C2675211
Disease or Syndrome
The hereditary ataxias are a group of genetic disorders characterized by slowly progressive incoordination of gait and often associated with poor coordination of hands, speech, and eye movements. Frequently, atrophy of the cerebellum occurs. In this GeneReview the hereditary ataxias are categorized by mode of inheritance and gene (or chromosomal locus) in which pathogenic variants occur.
Chromosome 15q11-q13 duplication syndrome
MedGen UID:
390767
Concept ID:
C2675336
Disease or Syndrome
The features of the chromosome 15q11-q13 duplication syndrome include autism, mental retardation, ataxia, seizures, developmental delays, and behavioral problems (Bundey et al., 1994; Burnside et al., 2011). See also chromosome 15q13.3 deletion syndrome (612001) and chromosome 15q11.2 deletion syndrome (615656). For a discussion of genetic heterogeneity of autism, see 209850.
22q11.2 duplication syndrome
MedGen UID:
436417
Concept ID:
C2675369
Disease or Syndrome
22q11.2 duplication is defined for this GeneReview as the presence of a common 3-Mb or 1.5-Mb proximal tandem duplication. The 22q11.2 duplication phenotype appears to be generally mild and highly variable; findings range from apparently normal to intellectual disability/learning disability, delayed psychomotor development, growth retardation, and/or hypotonia. The high frequency with which the 22q11.2 duplication is found in an apparently normal parent of a proband suggests that many individuals can harbor a duplication of 22q11.2 with no discernible phenotypic effect.
Mental retardation, autosomal dominant 5
MedGen UID:
382611
Concept ID:
C2675473
Disease or Syndrome
MRD5 is characterized by moderate to severe intellectual disability with delayed psychomotor development apparent in the first years of life. Some patients develop variable types of seizures, some have autism or autism spectrum disorder (see 209850), and some have acquired microcephaly (summary by Berryer et al., 2013).
Chromosome 6pter-p24 deletion syndrome
MedGen UID:
393396
Concept ID:
C2675486
Disease or Syndrome
Encephalopathy, acute, infection-induced, 3, suceptibility to
MedGen UID:
382634
Concept ID:
C2675556
Finding
Infection-induced acute encephalopathy 3 (IIAE3) is the susceptibility to recurrent acute necrotizing encephalopathy (ANE) caused by a heterozygous pathogenic variant in RANBP2. ANE refers to the specific neurologic presentation in which bilateral symmetric thalamic, midbrain, and/or hindbrain lesions occur within days following the onset of an acute viral illness caused by influenza A, influenza B, parainfluenza II, human herpesvirus 6, coxsackie virus, or an enterovirus. Although most IIAE3 occurs before age six years, first episodes have been observed in teenagers and adults. ANE begins within 12 hours to three or four days of the first awareness of viral symptoms (fever, cough, rhinorrhea, vomiting, diarrhea, and malaise). The most common sign of ANE is lethargy that progresses to coma (which may last for weeks) and seizures (in 50%). One third of affected individuals die during the acute phase of the encephalopathy; of the survivors, one half have permanent neurologic damage and the remainder have no discernible residual symptoms. Fifty per cent of persons with IIAE3 will have at least one repeat episode and some will have multiple repeat episodes
Holoprosencephaly 10
MedGen UID:
382704
Concept ID:
C2675857
Disease or Syndrome
Nonsyndromic holoprosencephaly is an abnormality of brain development that also affects the head and face. Normally, the brain divides into two halves (hemispheres) during early development. Holoprosencephaly occurs when the brain fails to divide properly into the right and left hemispheres. This condition is called nonsyndromic to distinguish it from other types of holoprosencephaly caused by genetic syndromes, chromosome abnormalities, or substances that cause birth defects (teratogens). The severity of nonsyndromic holoprosencephaly varies widely among affected individuals, even within the same family. Nonsyndromic holoprosencephaly can be grouped into four types according to the degree of brain division. From most to least severe, the types are known as alobar, semi-lobar, lobar, and middle interhemispheric variant (MIHV). In the most severe forms of nonsyndromic holoprosencephaly, the brain does not divide at all. These affected individuals have one central eye (cyclopia) and a tubular nasal structure (proboscis) located above the eye. Most babies with severe nonsyndromic holoprosencephaly die before birth or soon after. In the less severe forms, the brain is partially divided and the eyes are usually set close together (hypotelorism). The life expectancy of these affected individuals varies depending on the severity of symptoms. People with nonsyndromic holoprosencephaly often have a small head (microcephaly), although they can develop a buildup of fluid in the brain (hydrocephalus) that causes increased head size (macrocephaly). Other features may include an opening in the roof of the mouth (cleft palate) with or without a split in the upper lip (cleft lip), one front tooth (a single maxillary central incisor) instead of two, and a flat nasal bridge. The eyeballs may be abnormally small (microphthalmia) or absent (anophthalmia). Some individuals with nonsyndromic holoprosencephaly have a distinctive pattern of facial features, including a narrowing of the head at the temples, outside corners of the eyes that point upward (upslanting palpebral fissures), large ears, a short nose with upturned nostrils, and a broad and deep space between the nose and mouth (philtrum). In general, the severity of facial features is directly related to the severity of the brain abnormalities. However, individuals with mildly affected facial features can have severe brain abnormalities. Some people do not have apparent structural brain abnormalities but have some of the facial features associated with this condition. These individuals are considered to have a form of the disorder known as microform holoprosencephaly and are typically identified after the birth of a severely affected family member. Most people with nonsyndromic holoprosencephaly have developmental delay and intellectual disability. Affected individuals also frequently have a malfunctioning pituitary gland, which is a gland located at the base of the brain that produces several hormones. Because pituitary dysfunction leads to the partial or complete absence of these hormones, it can cause a variety of disorders. Most commonly, people with nonsyndromic holoprosencephaly and pituitary dysfunction develop diabetes insipidus, a condition that disrupts the balance between fluid intake and urine excretion. Dysfunction in other parts of the brain can cause seizures, feeding difficulties, and problems regulating body temperature, heart rate, and breathing. The sense of smell may be diminished (hyposmia) or completely absent (anosmia) if the part of the brain that processes smells is underdeveloped or missing.
Chromosome 1q21.1 duplication syndrome
MedGen UID:
382715
Concept ID:
C2675891
Disease or Syndrome
1q21.1 microduplication is a chromosomal change in which a small amount of genetic material on chromosome 1 is abnormally copied (duplicated). The duplication occurs on the long (q) arm of the chromosome at a location designated q21.1. Some people with a 1q21.1 microduplication have developmental delay and intellectual disability that is typically mild to moderate. Individuals with this condition can also have features of autism spectrum disorders. These disorders are characterized by impaired communication and socialization skills, as well as delayed development of speech and language. Expressive language skills (vocabulary and the production of speech) tend to be more impaired than receptive language skills (the ability to understand speech) in affected individuals. In childhood, 1q21.1 microduplications may also be associated with an increased risk of attention deficit hyperactivity disorder and other behavioral problems. Psychiatric disorders such as schizophrenia or mood disorders such as anxiety or depression occur in some affected individuals, usually during adulthood. Rarely, recurrent seizures (epilepsy) occur in people with a 1q21.1 microduplication. Some individuals with a 1q21.1 microduplication are born with malformations of the heart, including a particular combination of heart defects known as tetralogy of Fallot. Less commonly, other physical malformations such as the urethra opening on the underside of the penis (hypospadias) in males, inward- and upward-turning feet (clubfeet), or misalignment of the hip joint (hip dysplasia) are present at birth. Individuals with a 1q21.1 microduplication may also have a larger than average head size or taller than average adult stature. Some have slightly unusual facial features such as wide-set eyes or low-set ears. As adults, individuals with a 1q21.1 microduplication may be prone to develop cysts, swollen and knotted (varicose) veins, or carpal tunnel syndrome, which is characterized by numbness, tingling, and weakness in the hands and fingers. However, there is no particular pattern of physical abnormalities that characterizes 1q21.1 microduplications. Signs and symptoms related to the chromosomal change vary even among affected members of the same family. Some people with the duplication have no identified physical, intellectual, or behavioral abnormalities.
1q21.1 recurrent microdeletion
MedGen UID:
393913
Concept ID:
C2675897
Disease or Syndrome
The 1q21.1 microdeletion itself does not appear to lead to a clinically recognizable syndrome as some persons with the deletion have no obvious clinical findings and others have variable findings that most commonly include microcephaly (50%); mild intellectual disability (30%); mildly dysmorphic facial features; and eye abnormalities (26%). Other findings can include cardiac defects, genitourinary anomalies, skeletal malformations, and seizures (~15%). Psychiatric and behavioral abnormalities can include autism spectrum disorders, attention deficit hyperactivity disorder, autistic features, and sleep disturbances.
Pseudohypoparathyroidism type 1C
MedGen UID:
436554
Concept ID:
C2675910
Disease or Syndrome
Pseudohypoparathyroidism type Ic (PHP1C) is characterized by resistance to parathyroid hormone (PTH; 168450) as well as to other hormones. It is associated with a constellation of physical features referred to as Albright hereditary osteodystrophy (AHO), which includes short stature, obesity, round facies, subcutaneous ossifications, brachydactyly, and other skeletal anomalies. Some patients have mental retardation. Laboratory studies in patients with PHP Ic show a decreased cellular cyclic AMP (cAMP) response to infused PTH, but no defect in activity of the erythrocyte Gs protein (Mantovani and Spada, 2006).
Leukodystrophy, hypomyelinating, 6
MedGen UID:
436642
Concept ID:
C2676244
Disease or Syndrome
Hypomyelinating leukodystrophy-6, also known as hypomyelinating leukodystrophy with atrophy of the basal ganglia and cerebellum, is a neurologic disorder characterized by onset in infancy or early childhood of delayed motor development and gait instability, followed by extrapyramidal movement disorders, such as dystonia, choreoathetosis, rigidity, opisthotonus, and oculogyric crises, progressive spastic tetraplegia, ataxia, and, more rarely, seizures. Most patients have cognitive decline and speech delay, but some can function normally. Brain MRI shows a combination of hypomyelination, cerebellar atrophy, and atrophy or disappearance of the putamen. The disorder usually shows sporadic occurrence, but sibs may be affected if a parent is somatic mosaic for the mutation (summary by Simons et al., 2013). Hypomyelinating leukodystrophies (HLD) comprise a genetically heterogeneous entity in which there is a substantial permanent deficit in myelin deposition within the brain, resulting in neurologic deficits (van der Knaap et al., 2002). For a general phenotypic description and a discussion of genetic heterogeneity of hypomyelinating leukodystrophy, see 312080.
Pontocerebellar hypoplasia type 2B
MedGen UID:
393505
Concept ID:
C2676466
Disease or Syndrome
TSEN54-related pontocerebellar hypoplasia (PCH) includes three PCH types (PCH2, 4, and 5) that share characteristic neuroradiologic and neurologic findings. The three types (which differ mainly in life expectancy) were thought to be distinct entities before their molecular basis was known. Children with PCH2 usually succumb before age ten years, whereas those with PCH4 and 5 usually succumb as neonates. Children with PCH2 have generalized clonus, incoordination of sucking and swallowing, impaired motor and cognitive development with lack of voluntary motor development, central visual impairment, and an increased risk for malignant hyperthermia. Epilepsy is present in approximately 50%. Neonates with PCH4 often have seizures, multiple joint contractures (''arthrogryposis''), generalized clonus, and central respiratory impairment. PCH5, which resembles PCH4, has been described in one family.
Chromosome 1q43-q44 deletion syndrome
MedGen UID:
382926
Concept ID:
C2676727
Disease or Syndrome
Chromosome 1q43-q44 deletion syndrome is characterized by moderate to severe mental retardation, limited or no speech, and variable but characteristic facial features, including round face, prominent forehead, flat nasal bridge, hypertelorism, epicanthal folds, and low-set ears. Other features may include hypotonia, poor growth, microcephaly, agenesis of the corpus callosum, and seizures. The phenotype is variable, and not all features are observed in all patients, which may be explained in some cases by incomplete penetrance or variable expressivity (summary by Ballif et al., 2012).
Chromosome 2q32-q33 deletion syndrome
MedGen UID:
436765
Concept ID:
C2676739
Disease or Syndrome
Glass syndrome is characterized by intellectual disability of variable severity and dysmorphic facial features, including micrognathia, downslanting palpebral fissures, cleft palate, and crowded teeth. Additional features may include seizures, joint laxity, arachnodactyly, and happy demeanor (summary by Glass et al., 1989; Urquhart et al., 2009; Rainger et al., 2014).
Thrombophilia, hereditary, due to protein C deficiency, autosomal recessive
MedGen UID:
394120
Concept ID:
C2676759
Disease or Syndrome
Autosomal recessive protein C deficiency resulting from homozygous or compound heterozygous PROC mutations is a thrombotic condition that can manifest as a severe neonatal disorder or as a milder disorder with late-onset thrombophilia (Millar et al., 2000).
Joubert syndrome 9
MedGen UID:
382940
Concept ID:
C2676788
Disease or Syndrome
Joubert syndrome is a disorder that affects many parts of the body. The signs and symptoms of this condition vary among affected individuals, even among members of the same family. The hallmark feature of Joubert syndrome is a brain abnormality called the molar tooth sign, which can be seen on brain imaging studies such as magnetic resonance imaging (MRI). This sign results from the abnormal development of regions near the back of the brain called the cerebellar vermis and the brainstem. The molar tooth sign got its name because the characteristic brain abnormalities resemble the cross-section of a molar tooth when seen on an MRI. Most infants with Joubert syndrome have weak muscle tone (hypotonia) in infancy, which evolves into difficulty coordinating movements (ataxia) in early childhood. Other characteristic features of the condition include episodes of unusually fast or slow breathing in infancy and abnormal eye movements. Most affected individuals have delayed development and intellectual disability, which range from mild to severe. Distinctive facial features are also characteristic of Joubert syndrome; these include a broad forehead, arched eyebrows, droopy eyelids (ptosis), widely spaced eyes, low-set ears, and a triangle-shaped mouth. Joubert syndrome can include a broad range of additional signs and symptoms. The condition is sometimes associated with other eye abnormalities (such as retinal dystrophy, which can cause vision loss), kidney disease, liver disease, skeletal abnormalities (such as the presence of extra fingers and toes), and hormone (endocrine) problems. When the characteristic features of Joubert syndrome occur in combination with one or more of these additional signs and symptoms, researchers refer to the condition as "Joubert syndrome and related disorders (JSRD)."
Leukodystrophy, hypomyelinating, 4
MedGen UID:
383026
Concept ID:
C2677109
Disease or Syndrome
Cerebroretinal microangiopathy with calcifications and cysts
MedGen UID:
383079
Concept ID:
C2677299
Disease or Syndrome
Cerebroretinal microangiopathy with calcifications and cysts (CRMCC), also known as Coats plus syndrome, is an autosomal recessive pleomorphic disorder characterized primarily by intracranial calcifications, leukodystrophy, and brain cysts, resulting in spasticity, ataxia, dystonia, seizures, and cognitive decline. Patients also have retinal telangiectasia and exudates (Coats disease) as well as extraneurologic manifestations, including osteopenia with poor bone healing and a high risk of gastrointestinal bleeding and portal hypertension caused by vasculature ectasias in the stomach, small intestine, and liver. Some individuals also have hair, skin, and nail changes, as well as anemia and thrombocytopenia (summary by Anderson et al., 2012 and Polvi et al., 2012). Leukoencephalopathy, brain calcifications, and cysts (LCC), also known as Labrune syndrome (614561), has similar central nervous system features as CRMCC in the absence of extraneurologic or systemic manifestations. Although Coats plus syndrome and Labrune syndrome were initially thought to be manifestations of the same disorder, namely CRMCC, molecular evidence has excluded mutations in the CTC1 gene in patients with Labrune syndrome, suggesting that the 2 disorders are not allelic (Anderson et al., 2012; Polvi et al., 2012). Some features of CRMCC resemble those observed in dyskeratosis congenita (see, e.g., 127550), which is a clinically and genetically heterogeneous telomere-related genetic disorder.
Coenzyme Q10 deficiency, primary, 4
MedGen UID:
436985
Concept ID:
C2677589
Disease or Syndrome
Primary coenzyme Q10 deficiency-4 is an autosomal recessive disorder characterized by childhood-onset of cerebellar ataxia and exercise intolerance. Some affected individuals develop seizures and have mild mental impairment, indicating variable severity. Oral coenzyme Q10 supplementation does not result in significant improvement of neurologic symptoms (summary by Mollet et al., 2008 and Lagier-Tourenne et al., 2008). For a general phenotypic description and a discussion of genetic heterogeneity of primary coenzyme Q10 deficiency, see COQ10D1 (607426).
Congenital disorder of glycosylation type 1N
MedGen UID:
383145
Concept ID:
C2677590
Disease or Syndrome
Congenital disorders of N-linked glycosylation (abbreviated here as CDG-N-linked), are a group of disorders of N-linked oligosaccharides caused by deficiency in 42 different enzymes in the N-linked synthetic pathway. Most commonly, the disorders begin in infancy; manifestations range from severe developmental delay and hypotonia with multiple organ system involvement to hypoglycemia and protein-losing enteropathy with normal development. However, most types have been described in only a few individuals, and thus understanding of the phenotypes is limited. In PMM2-CDG (CDG-Ia), the most common type reported, the clinical presentation and course are highly variable, ranging from death in infancy to mild involvement in adults.
15q13.3 microdeletion syndrome
MedGen UID:
393784
Concept ID:
C2677613
Disease or Syndrome
Heterozygous deletion of chromosome 15q13.3 is associated with a highly variable phenotype, even within families segregating the same deletion. Individuals with the deletion may have mild to moderate mental retardation or learning difficulties, or may have no cognitive deficits. Some individuals have epilepsy. Various dysmorphic features have been described, but there is no consistent or recognizable phenotype (review by van Bon et al., 2009). Patients with homozygous deletions in this region have severe neurodevelopmental problems, with epileptic encephalopathy, hypotonia, and poor growth (Endris et al., 2010).
Stevenson-Carey syndrome
MedGen UID:
383183
Concept ID:
C2677763
Disease or Syndrome
Ventricular tachycardia, catecholaminergic polymorphic, 2
MedGen UID:
393837
Concept ID:
C2677794
Disease or Syndrome
Catecholaminergic polymorphic ventricular tachycardia (CPVT) is characterized by episodic syncope occurring during exercise or acute emotion in individuals without structural cardiac abnormalities. Arrhythmias may be well tolerated, with only mild symptoms such as dizziness or lypothymia. The underlying cause of these episodes is the onset of fast ventricular tachycardia (bidirectional or polymorphic). Spontaneous recovery occurs when these arrhythmias self-terminate. In other instances, ventricular tachycardia may degenerate into ventricular fibrillation and cause sudden death if cardiopulmonary resuscitation is not readily available. The mean age of onset of symptoms (usually a syncopal episode) of CPVT is between age seven and twelve years; onset as late as the fourth decade of life has been reported. If untreated, CPVT is highly lethal, as approximately 30% of affected individuals experience at least one cardiac arrest and up to 80% one or more syncopal spells. Sudden death may be the first manifestation of the disease.
Mental retardation and microcephaly with pontine and cerebellar hypoplasia
MedGen UID:
437070
Concept ID:
C2677903
Disease or Syndrome
Mental retardation and microcephaly with pontine and cerebellar hypoplasia (MICPCH) is an X-linked disorder affecting females and characterized by severe intellectual disability, microcephaly, and variable degrees of pontocerebellar hypoplasia. Affected individuals have very poor psychomotor development, often without independent ambulation or speech, and axial hypotonia with or without hypertonia. Some may have sensorineural hearing loss or eye anomalies. Dysmorphic features include overall poor growth, severe microcephaly (-3.5 to -10 SD), broad nasal bridge and tip, large ears, long philtrum, micrognathia, and hypertelorism (summary by Moog et al., 2011).
STAR syndrome
MedGen UID:
394424
Concept ID:
C2678045
Disease or Syndrome
Mental retardation, X-linked, syndromic, wu type
MedGen UID:
437111
Concept ID:
C2678051
Disease or Syndrome
Christianson syndrome
MedGen UID:
394455
Concept ID:
C2678194
Disease or Syndrome
Christianson syndrome is an X-linked neurodevelopmental and progressive mental retardation syndrome characterized by microcephaly, impaired ocular movements, severe global developmental delay, developmental regression, hypotonia, abnormal movements, and early-onset seizures of variable types. Female carriers may be mildly affected (summary by Schroer et al., 2010 and Pescosolido et al., 2014).
Chromosome 22q11.2 deletion syndrome, distal
MedGen UID:
395634
Concept ID:
C2678480
Disease or Syndrome
Temple-Baraitser syndrome
MedGen UID:
395636
Concept ID:
C2678486
Disease or Syndrome
Temple-Baraitser syndrome is a rare developmental disorder characterized by severe mental retardation and anomalies of the first ray of the upper and lower limbs with absence/hypoplasia of the nails. Most patients also have seizures; various dysmorphic facial features have been reported (summary by Jacquinet et al., 2010).
Deafness, autosomal recessive 81
MedGen UID:
473597
Concept ID:
C2681413
Gene or Genome
Perrault syndrome (PRLTS) is an autosomal recessive disorder characterized by sensorineural hearing loss (SNHL) and premature ovarian failure (POF) secondary to ovarian dysgenesis. Affected males have SNHL but show normal pubertal development. A spectrum of additional clinical features, including cerebellar ataxia, learning disability, and peripheral neuropathy, have been described in some affected individuals (summary by Jenkinson et al., 2013). For a discussion of genetic heterogeneity of Perrault syndrome, see PRLTS1 (233400).
Dihydropyrimidine dehydrogenase deficiency
MedGen UID:
404073
Concept ID:
C2720286
Disease or Syndrome
Dihyropyrimidine dehydrogenase deficiency shows large phenotypic variability, ranging from no symptoms to a convulsive disorder with motor and mental retardation in homozygous patients. In addition, homozygous and heterozygous mutation carriers can develop severe toxicity after the administration of the antineoplastic drug 5-fluorouracil (5FU), which is also catabolized by the DPYD enzyme. This is an example of a pharmacogenetic disorder (Van Kuilenburg et al., 1999). Since there is no correlation between genotype and phenotype in DPD deficiency, it appears that the deficiency is a necessary, but not sufficient, prerequisite for the development of clinical abnormalities (Van Kuilenburg et al., 1999; Enns et al., 2004).
Combined d-2- and l-2-hydroxyglutaric aciduria
MedGen UID:
412535
Concept ID:
C2746066
Disease or Syndrome
Combined D-2- and L-2-hydroxyglutaric aciduria (D-2-HG and L-2-HG) is an autosomal recessive neurometabolic disorder characterized by neonatal-onset encephalopathy with severe muscular weakness, intractable seizures, respiratory distress, and lack of psychomotor development resulting in early death. Brain imaging shows abnormalities including enlarged ventricles, delayed myelination, and germinal layer cysts (summary by Muntau et al., 2000). See also isolated L-2-hydroxyglutaric aciduria (236792) and isolated D-2-hydroxyglutaric aciduria (see 600721).
SeSAME syndrome
MedGen UID:
411243
Concept ID:
C2748572
Disease or Syndrome
Mental retardation, X-linked 96
MedGen UID:
411731
Concept ID:
C2749021
Disease or Syndrome
Chromosome Xp11.23-p11.22 duplication syndrome
MedGen UID:
440690
Concept ID:
C2749022
Disease or Syndrome
Atypical hemolytic-uremic syndrome 1
MedGen UID:
412743
Concept ID:
C2749604
Finding
Hemolytic-uremic syndrome (HUS) is characterized by hemolytic anemia, thrombocytopenia, and renal failure caused by platelet thrombi in the microcirculation of the kidney and other organs. Typical (acquired) HUS is triggered by infectious agents such as strains of E. coli (Stx-E. coli) that produce powerful Shiga-like exotoxins, whereas atypical HUS (aHUS) can be genetic, acquired, or idiopathic (of unknown cause). Onset of atypical HUS ranges from prenatal to adulthood. Individuals with genetic atypical HUS frequently experience relapse even after complete recovery following the presenting episode. Sixty percent of genetic aHUS progresses to end-stage renal disease (ESRD).
Mitochondrial DNA depletion syndrome, encephalomyopathic form, with renal tubulopathy
MedGen UID:
412815
Concept ID:
C2749861
Disease or Syndrome
Mitochondrial DNA depletion syndrome-8A is a severe autosomal recessive disorder characterized by neonatal hypotonia, lactic acidosis, and neurologic deterioration. Renal tubular involvement may also occur (Bourdon et al., 2007). Mitochondrial DNA depletion syndrome-8B is characterized by ophthalmoplegia, ptosis, gastrointestinal dysmotility, cachexia, peripheral neuropathy, and brain MRI changes, known as the MNGIE phenotype (Shaibani et al., 2009). For a discussion of genetic heterogeneity of mtDNA depletion syndromes, see MTDPS1 (603041).
Mitochondrial DNA depletion syndrome 5 (encephalomyopathic with or without methylmalonic aciduria)
MedGen UID:
413170
Concept ID:
C2749864
Disease or Syndrome
SUCLA2-related mitochondrial DNA (mtDNA) depletion syndrome is characterized by onset of severe hypotonia in early infancy (birth to five months); severe muscular atrophy with failure to achieve independent ambulation; progressive scoliosis or kyphosis; dystonia and/or hyperkinesias (i.e., athetoid or choreiform movements); epilepsy (infantile spasms or generalized convulsions with onset from birth to three years) in a few children; postnatal growth retardation; and severe sensorineural hearing impairment. The outcome is poor with early lethality.
Chromosome 3q29 microduplication syndrome
MedGen UID:
440897
Concept ID:
C2749873
Disease or Syndrome
Spastic paraplegia 18
MedGen UID:
442343
Concept ID:
C2749936
Disease or Syndrome
Spastic paraplegia-18 is a severe autosomal recessive neurologic disorder characterized by onset in early childhood of progressive spastic paraplegia resulting in motor disability. Most affected individuals have severe psychomotor retardation. Some may develop significant joint contractures (summary by Alazami et al., 2011 and Yildirim et al., 2011).
Pitt-Hopkins-like syndrome 1
MedGen UID:
413258
Concept ID:
C2750246
Disease or Syndrome
Polymicrogyria, asymmetric
MedGen UID:
413259
Concept ID:
C2750247
Disease or Syndrome
Polymicrogyria is a malformation of cortical development characterized by an excessive number of small gyri with abnormal lamination (Chang et al., 2006). See 606854 for a description of hereditary bilateral frontoparietal polymicrogyria (BFPP).
Spastic paraplegia 44, autosomal recessive
MedGen UID:
413042
Concept ID:
C2750784
Disease or Syndrome
Mental retardation, autosomal recessive 13
MedGen UID:
442564
Concept ID:
C2750791
Disease or Syndrome
Polymicrogyria with optic nerve hypoplasia
MedGen UID:
442565
Concept ID:
C2750798
Disease or Syndrome
Chromosome 5p13 duplication syndrome
MedGen UID:
416385
Concept ID:
C2750805
Disease or Syndrome
Amyloidogenic transthyretin amyloidosis
MedGen UID:
414031
Concept ID:
C2751492
Disease or Syndrome
Familial transthyretin (TTR) amyloidosis is characterized by a slowly progressive peripheral sensorimotor neuropathy and autonomic neuropathy as well as non-neuropathic changes of cardiomyopathy, nephropathy, vitreous opacities, and CNS amyloidosis. The disease usually begins in the third to fifth decade in persons from endemic foci in Portugal and Japan; onset is later in persons from other areas. Typically, sensory neuropathy starts in the lower extremities with paresthesias and hypesthesias of the feet, followed within a few years by motor neuropathy. In some persons, particularly those with early onset disease, autonomic neuropathy is the first manifestation of the condition; findings can include: orthostatic hypotension, constipation alternating with diarrhea, attacks of nausea and vomiting, delayed gastric emptying, sexual impotence, anhidrosis, and urinary retention or incontinence. Cardiac amyloidosis is mainly characterized by progressive cardiomyopathy. Individuals with leptomeningeal amyloidosis may have the following CNS findings: dementia, psychosis, visual impairment, headache, seizures, motor paresis, ataxia, myelopathy, hydrocephalus, or intracranial hemorrhage.
mitochondrial 3-hydroxy-3-methylglutaryl-CoA synthase deficiency
MedGen UID:
414399
Concept ID:
C2751532
Disease or Syndrome
Mitochondrial HMG-CoA synthase deficiency is an inherited metabolic disorder caused by a defect in the enzyme that regulates the formation of ketone bodies. Patients present with hypoketotic hypoglycemia, encephalopathy, and hepatomegaly, usually precipitated by an intercurrent infection or prolonged fasting (summary by Aledo et al., 2006).
Cerebral amyloid angiopathy, APP-related
MedGen UID:
414044
Concept ID:
C2751536
Disease or Syndrome
Cerebral amyloid angiopathy, or cerebroarterial amyloidosis, refers to a pathologic process in which amyloid protein progressively deposits in cerebral blood vessel walls with subsequent degenerative vascular changes that usually result in spontaneous cerebral hemorrhage, ischemic lesions, and progressive dementia. APP-related CAA is the most common form of CAA (Revesz et al., 2003, 2009).
Cerebral folate deficiency
MedGen UID:
442763
Concept ID:
C2751584
Disease or Syndrome
This is an autosomal recessive disorder resulting from brain-specific folate deficiency early in life. Onset is apparent in late infancy with severe developmental regression, movement disturbances, epilepsy, and leukodystrophy. Recognition and diagnosis of this disorder is critical because folinic acid therapy can reverse the clinical symptoms and improve brain abnormalities and function (Steinfeld et al,. 2009).
Leukoencephalopathy, cystic, without megalencephaly
MedGen UID:
416646
Concept ID:
C2751843
Disease or Syndrome
Hypomyelination, global cerebral
MedGen UID:
414492
Concept ID:
C2751855
Disease or Syndrome
Microcephaly, growth retardation, cataract, hearing loss, and unusual appearance
MedGen UID:
416652
Concept ID:
C2751870
Disease or Syndrome
Cerebral palsy, spastic quadriplegic, 1
MedGen UID:
442852
Concept ID:
C2751938
Disease or Syndrome
Cerebral palsy (CP) is defined as a nonprogressive but not unchanging disorder of posture or movement, caused by an abnormality of the brain and first evident at the stage of rapid brain development (Hughes and Newton, 1992). The most common forms result from factors surrounding difficulties before or at birth, such as severe perinatal asphyxia, congenital infection, prematurity, and multiple pregnancy (Blair and Stanley, 1988; Stanley, 1994). More rarely, familial clustering or absence of pre- or postpartum events indicate that there are genetic forms of the disorder (Lynex et al., 2004). Cerebral palsy can be classified according to the type of movement disorder: spastic cerebral palsy accounts for approximately 60% of cases and can be subdivided into hemiplegic, diplegic, quadriplegic, and monoplegic types, whereas other forms include athetoid/dyskinetic, ataxic (605388), and mixed (Gustavson et al., 1969). Genetic Heterogeneity of Spastic Quadriplegic Cerebral Palsy See also CPSQ2 (612900), caused by deletion of the ANKRD15 gene (KANK1; 607704) inherited on the paternal allele. Related phenotypes that were formerly classified in the CPSQ series include spastic paraplegia-47 (SPG47; 614066), spastic paraplegia-50 (SPG50; 612936), spastic paraplegia-51 (SPG51; 613744), and spastic paraplegia-52 (614067).
Growth retardation, developmental delay, coarse facies, and early death
MedGen UID:
414158
Concept ID:
C2752001
Disease or Syndrome
Kallmann syndrome 3
MedGen UID:
419286
Concept ID:
C2930927
Disease or Syndrome
Isolated gonadotropin-releasing hormone (GnRH) deficiency (IGD) is characterized by inappropriately low serum concentrations of the gonadotropins LH (luteinizing hormone) and FSH (follicle-stimulating hormone) in the setting of hypogonadism. IGD is associated with a normal sense of smell (normosmic IGD) in approximately 40% of affected individuals and an impaired sense of smell (Kallmann syndrome [KS]) in approximately 60%. IGD can first be apparent in infancy, adolescence, or adulthood. Infant boys with congenital (i.e., present at birth) IGD often have micropenis and cryptorchidism. Adolescents and adults with IGD have clinical evidence of hypogonadism and incomplete sexual maturation on physical examination. Adult males with IGD tend to have prepubertal testicular volume (i.e., <4 mL), absence of secondary sexual features (e.g., facial and axillary hair growth, deepening of the voice), decreased muscle mass, diminished libido, erectile dysfunction, and infertility. Adult females have little or no breast development and primary amenorrhea. Although skeletal maturation is delayed, the rate of linear growth is usually normal except for the absence of a distinct pubertal growth spurt.
Clark-Baraitser syndrome
MedGen UID:
443983
Concept ID:
C2931130
Disease or Syndrome
Chromosome 3pter-p25 deletion syndrome
MedGen UID:
419050
Concept ID:
C2931337
Cell or Molecular Dysfunction
Characteristic features of the distal 3p- syndrome include low birth weight, microcephaly, trigonocephaly, hypotonia, psychomotor and growth retardation, ptosis, telecanthus, downslanting palpebral fissures, and micrognathia. Postaxial polydactyly, renal anomalies, cleft palate, congenital heart defects (especially atrioventricular septal defects), preauricular pits, sacral dimple, and gastrointestinal anomalies are variable features. Although intellectual deficits are almost invariably associated with cytogenetically visible 3p deletions, rare patients with a 3p26-p25 deletion and normal intelligence or only mild abnormalities have been described (summary by Shuib et al., 2009).
Cleft lip/palate-ectodermal dysplasia syndrome
MedGen UID:
444067
Concept ID:
C2931488
Disease or Syndrome
Deficiency of pyrroline-5-carboxylate reductase
MedGen UID:
419175
Concept ID:
C2931835
Disease or Syndrome
Hyperprolinemia is an excess of a particular protein building block (amino acid), called proline, in the blood. This condition generally occurs when proline is not broken down properly by the body. There are two inherited forms of hyperprolinemia, called type I and type II. People with hyperprolinemia type I often do not show any symptoms, although they have proline levels in their blood between 3 and 10 times the normal level. Some individuals with hyperprolinemia type I exhibit seizures, intellectual disability, or other neurological or psychiatric problems. Hyperprolinemia type II results in proline levels in the blood between 10 and 15 times higher than normal, and high levels of a related compound called pyrroline-5-carboxylate. This form of the disorder has signs and symptoms that vary in severity, and is more likely than type I to involve seizures or intellectual disability. Hyperprolinemia can also occur with other conditions, such as malnutrition or liver disease. In particular, individuals with conditions that cause elevated levels of lactic acid in the blood (lactic acidemia) may have hyperprolinemia as well, because lactic acid inhibits the breakdown of proline.
Crigler-Najjar syndrome, type I
MedGen UID:
453386
Concept ID:
C2981159
Disease or Syndrome
Chromosome 16p12.1 deletion syndrome
MedGen UID:
460626
Concept ID:
C3149276
Disease or Syndrome
16p12.2 microdeletion is characterized by variable clinical findings that do not constitute a recognizable syndrome. Of note, the significant bias in ascertainment of individuals undergoing clinical chromosomal microarray analysis (i.e., children with intellectual disability and developmental delay; individuals with schizophrenia) makes it difficult to accurately associate specific phenotypes to the 16p12.2 microdeletion. Findings commonly observed in children (probands) with this deletion include: developmental delay, cognitive impairment (ranges from mild to profound), growth impairment (including short stature), cardiac malformations, epilepsy, and psychiatric and/or behavioral problems. Other findings can include: hearing loss, dental abnormalities, renal and genital anomalies (the latter in males), and cleft palate ± cleft lip.
Mitochondrial DNA depletion syndrome 2
MedGen UID:
461100
Concept ID:
C3149750
Disease or Syndrome
TK2-related mitochondrial DNA (mtDNA) depletion syndrome is a phenotypic continuum that ranges from severe to mild. To date, approximately 45 individuals with a molecularly confirmed diagnosis have been reported. The most typical presentation, which occurs in infants and children, is progressive muscle disease characterized by generalized hypotonia, proximal muscle weakness, loss of previously acquired motor skills, poor feeding, and respiratory difficulties leading to respiratory failure and death within a few years after diagnosis. Other severe presentations include: Rapidly progressive proximal muscle weakness in newborns with encephalopathy, epilepsy, and early death; A spinal muscular atrophy-like presentation; Progressive myopathy with dystrophic changes (including sensorineural hearing loss); Hepatomegaly with elevated liver enzymes associated with the severe early-onset myopathy. Milder presentations include: Late-onset proximal muscle weakness and prolonged survival; Adult-onset forms with progressive mitochondrial myopathy; Chronic progressive external ophthalmoplegia with proximal muscle weakness associated with multiple mtDNA deletions and no mtDNA depletion.
16p11.2 deletion syndrome
MedGen UID:
461504
Concept ID:
C3150154
Disease or Syndrome
16p11.2 microdeletion is characterized by developmental delay, intellectual disability, and/or autism spectrum disorder (ASD). Developmental delays are more related to diminished language and cognitive function than motor disability. Although IQ scores range from mild intellectual disability to normal, those with IQ scores in the average range typically have other developmental issues such as language delay or ASD. Expressive language appears to be more affected than receptive language. Individuals with 16p11.2 microdeletion are at increased risk of being overweight and obese, and may be at higher than average risk for seizures and/or EEG abnormalities. As a group, they do not have a higher risk for other severe neurologic disorders, or other medical problems.
Chromosome 6q24-q25 deletion syndrome
MedGen UID:
461565
Concept ID:
C3150215
Disease or Syndrome
Homocystinuria due to CBS deficiency
MedGen UID:
461694
Concept ID:
C3150344
Disease or Syndrome
Homocystinuria caused by cystathionine ß-synthase (CBS) deficiency is characterized by developmental delay/intellectual disability, ectopia lentis and/or severe myopia, skeletal abnormalities (excessive height and length of the limbs), and thromboembolism. Expressivity is variable for all of the clinical signs. Two phenotypic variants are recognized, B6-responsive homocystinuria and B6-non-responsive homocystinuria. B6-responsive homocystinuria is typically, but not always, milder than the non-responsive variant. In the majority of untreated affected individuals, ectopia lentis occurs by age eight years. Individuals are often tall and slender with an asthenic (‘marfanoid’) habitus and are prone to osteoporosis. Thromboembolism is the major cause of early death and morbidity. IQ in individuals with untreated homocystinuria ranges widely, from 10 to 138. In B6-responsive individuals the mean IQ is 79 versus 57 for those who are B6 non-responsive. Other features that may occur include: seizures, psychiatric problems, extrapyramidal signs (e.g., dystonia), hypopigmentation, malar flush, livedo reticularis, and pancreatitis.
Congenital muscular dystrophy-dystroglycanopathy with brain and eye anomalies, type A2
MedGen UID:
461761
Concept ID:
C3150411
Disease or Syndrome
Congenital muscular dystrophy (CMD) is a clinically and genetically heterogeneous group of inherited muscle disorders. Muscle weakness typically presents from birth to early infancy. Affected infants typically appear "floppy" with low muscle tone and poor spontaneous movements. Affected children may present with delay or arrest of gross motor development together with joint and/or spinal rigidity. Muscle weakness may improve, worsen, or stabilize in the short term; however, with time progressive weakness and joint contractures, spinal deformities, and respiratory compromise may affect quality of life and life span. The main CMD subtypes, grouped by involved protein function and gene in which causative mutations occur, are laminin alpha-2 (merosin) deficiency (MDC1A), collagen VI-deficient CMD, the dystroglycanopathies (caused by mutations in POMT1, POMT2, FKTN, FKRP, LARGE, POMGNT1, and ISPD), SEPN1-related CMD (previously known as rigid spine syndrome, RSMD1) and LMNA-related CMD (L-CMD). Several less known CMD subtypes have been reported in a limited number of individuals. Cognitive impairment ranging from intellectual disability to mild cognitive delay, structural brain and/or eye abnormalities, and seizures are found almost exclusively in the dystroglycanopathies while white matter abnormalities without major cognitive involvement tend to be seen in the laminin alpha-2-deficient subtype.
Nephronophthisis-like nephropathy 1
MedGen UID:
461769
Concept ID:
C3150419
Disease or Syndrome
Nephronophthisis is an autosomal recessive cystic kidney disease characterized by onset of end-stage renal failure in the first 3 decades of life. The disorder is often associated with extrarenal manifestations, including liver fibrosis, retinal degeneration, and central nervous system abnormalities (summary by O'Toole et al., 2010). For a general phenotypic description and a discussion of genetic heterogeneity of nephronophthisis, see NPHP1 (256100).
15q24 deletion syndrome
MedGen UID:
462024
Concept ID:
C3150674
Disease or Syndrome
The 15q24 microdeletion syndrome is characterized by global developmental delay; mild to severe (usually at least moderate) intellectual disability; facial dysmorphisms; congenital malformations of the hands and feet, eye, and genitalia; joint laxity; and growth retardation and failure to thrive. Less common findings include: seizures; conductive and sensorineural hearing loss; hypospadias and/ or micropenis. Males and females are affected equally.
Mental retardation, stereotypic movements, epilepsy, and/or cerebral malformations
MedGen UID:
462050
Concept ID:
C3150700
Disease or Syndrome
Rett syndrome, congenital variant
MedGen UID:
462055
Concept ID:
C3150705
Disease or Syndrome
The congenital variant of Rett syndrome is a severe neurodevelopmental disorder with features of classic Rett syndrome (RTT; 312750), but earlier onset in the first months of life. Classic Rett syndrome shows later onset and is caused by mutation in the MECP2 gene (300005).
Chromosome 14q11-q22 deletion syndrome
MedGen UID:
462057
Concept ID:
C3150707
Disease or Syndrome
Early infantile epileptic encephalopathy 5
MedGen UID:
462081
Concept ID:
C3150731
Disease or Syndrome
Congenital disorder of glycosylation type 2J
MedGen UID:
462086
Concept ID:
C3150736
Disease or Syndrome
Congenital disorders of N-linked glycosylation (abbreviated here as CDG-N-linked), are a group of disorders of N-linked oligosaccharides caused by deficiency in 42 different enzymes in the N-linked synthetic pathway. Most commonly, the disorders begin in infancy; manifestations range from severe developmental delay and hypotonia with multiple organ system involvement to hypoglycemia and protein-losing enteropathy with normal development. However, most types have been described in only a few individuals, and thus understanding of the phenotypes is limited. In PMM2-CDG (CDG-Ia), the most common type reported, the clinical presentation and course are highly variable, ranging from death in infancy to mild involvement in adults.
Chromosome 4q21 deletion syndrome
MedGen UID:
462106
Concept ID:
C3150756
Disease or Syndrome
D-2-hydroxyglutaric aciduria 2
MedGen UID:
462259
Concept ID:
C3150909
Disease or Syndrome
2-hydroxyglutaric aciduria is a condition that causes progressive damage to the brain. The major types of this disorder are called D-2-hydroxyglutaric aciduria (D-2-HGA), L-2-hydroxyglutaric aciduria (L-2-HGA), and combined D,L-2-hydroxyglutaric aciduria (D,L-2-HGA). The main features of D-2-HGA are delayed development, seizures, weak muscle tone (hypotonia), and abnormalities in the largest part of the brain (the cerebrum), which controls many important functions such as muscle movement, speech, vision, thinking, emotion, and memory. Researchers have described two subtypes of D-2-HGA, type I and type II. The two subtypes are distinguished by their genetic cause and pattern of inheritance, although they also have some differences in signs and symptoms. Type II tends to begin earlier and often causes more severe health problems than type I. Type II may also be associated with a weakened and enlarged heart (cardiomyopathy), a feature that is typically not found with type I. L-2-HGA particularly affects a region of the brain called the cerebellum, which is involved in coordinating movements. As a result, many affected individuals have problems with balance and muscle coordination (ataxia). Additional features of L-2-HGA can include delayed development, seizures, speech difficulties, and an unusually large head (macrocephaly). Typically, signs and symptoms of this disorder begin during infancy or early childhood. The disorder worsens over time, usually leading to severe disability by early adulthood. Combined D,L-2-HGA causes severe brain abnormalities that become apparent in early infancy. Affected infants have severe seizures, weak muscle tone (hypotonia), and breathing and feeding problems. They usually survive only into infancy or early childhood.
Congenital disorder of glycosylation type 1P
MedGen UID:
462263
Concept ID:
C3150913
Disease or Syndrome
Congenital disorders of N-linked glycosylation (abbreviated here as CDG-N-linked), are a group of disorders of N-linked oligosaccharides caused by deficiency in 42 different enzymes in the N-linked synthetic pathway. Most commonly, the disorders begin in infancy; manifestations range from severe developmental delay and hypotonia with multiple organ system involvement to hypoglycemia and protein-losing enteropathy with normal development. However, most types have been described in only a few individuals, and thus understanding of the phenotypes is limited. In PMM2-CDG (CDG-Ia), the most common type reported, the clinical presentation and course are highly variable, ranging from death in infancy to mild involvement in adults.
Mitochondrial DNA depletion syndrome 4B, MNGIE type
MedGen UID:
462264
Concept ID:
C3150914
Disease or Syndrome
Mitochondrial DNA depletion syndrome-4B is an autosomal recessive progressive multisystem disorder clinically characterized by chronic gastrointestinal dysmotility and pseudoobstruction, cachexia, progressive external ophthalmoplegia (PEO), axonal sensory ataxic neuropathy, and muscle weakness (van Goethem et al., 2003). For a discussion of genetic heterogeneity of autosomal recessive mtDNA depletion syndromes, see MTDPS1 (603041).
Microcephaly, postnatal progressive, with seizures and brain atrophy
MedGen UID:
462271
Concept ID:
C3150921
Disease or Syndrome
Chromosome 17q11.2 deletion syndrome, 1.4-mb
MedGen UID:
462278
Concept ID:
C3150928
Disease or Syndrome
Approximately 5 to 20% of all patients with neurofibromatosis type I (162200) carry a heterozygous deletion of approximately 1.4 Mb involving the NF1 gene and contiguous genes lying in its flanking regions (Riva et al., 2000; Jenne et al., 2001), which is caused by nonallelic homologous recombination of NF1 repeats A and C (Dorschner et al., 2000). The 'NF1 microdeletion syndrome' is often characterized by a more severe phenotype than that observed in the majority of NF1 patients. In particular, patients with NF1 microdeletion often show variable facial dysmorphism, mental retardation, developmental delay, an excessive number of early-onset neurofibromas (Venturin et al., 2004), and an increased risk for malignant peripheral nerve sheath tumors (De Raedt et al., 2003).
LEOPARD syndrome 3
MedGen UID:
462321
Concept ID:
C3150971
Disease or Syndrome
Multiple lentigines syndrome (formerly called LEOPARD syndrome) is a condition that affects many areas of the body. The characteristic features associated with the condition include brown skin spots called lentigines that are similar to freckles, abnormalities in the electrical signals that control the heartbeat, widely spaced eyes (ocular hypertelorism), a narrowing of the artery from the heart to the lungs (pulmonary stenosis), abnormalities of the genitalia, short stature, and hearing loss. These features vary, however, even among affected individuals in the same family. Not all individuals affected with multiple lentigines syndrome have all the characteristic features of this condition. The lentigines seen in multiple lentigines syndrome typically first appear in mid-childhood, mostly on the face, neck, and upper body. Affected individuals may have thousands of brown skin spots by the time they reach puberty. Unlike freckles, the appearance of lentigines has nothing to do with sun exposure. In addition to lentigines, people with this condition may have lighter brown skin spots called café-au-lait spots. Café-au-lait spots tend to develop before the lentigines, appearing within the first year of life in most affected people. Abnormal electrical signaling in the heart can be a sign of other heart problems. Of the people with multiple lentigines syndrome who have heart problems, about 80 percent have hypertrophic cardiomyopathy, which is a thickening of the heart muscle that forces the heart to work harder to pump blood. The hypertrophic cardiomyopathy in affected individuals most often affects the lower left chamber of the heart (the left ventricle). Up to 20 percent of people with multiple lentigines syndrome who have heart problems have pulmonary stenosis. People with multiple lentigines syndrome can have a distinctive facial appearance. In addition to ocular hypertelorism, affected individuals may have droopy eyelids (ptosis), thick lips, and low-set ears. Abnormalities of the genitalia occur most often in males with multiple lentigines syndrome. The most common abnormality in affected males is undescended testes (cryptorchidism). Other males may have a urethra that opens on the underside of the penis (hypospadias). Males with multiple lentigines syndrome may have a reduced ability to have biological children (decreased fertility). Females with multiple lentigines syndrome may have poorly developed ovaries and delayed puberty. At birth, people with multiple lentigines syndrome are typically of normal weight and height, but in some, growth slows over time. This slow growth results in short stature in 50 to 75 percent of people with multiple lentigines syndrome. Approximately 20 percent of individuals with multiple lentigines syndrome develop hearing loss. This hearing loss is caused by abnormalities in the inner ear (sensorineural deafness) and can be present from birth or develop later in life. Other signs and symptoms of multiple lentigines syndrome include learning disorders, mild developmental delay, a sunken or protruding chest, and extra folds of skin on the back of the neck. Many of the signs and symptoms of multiple lentigines syndrome also occur in a similar disorder called Noonan syndrome. It can be difficult to tell the two disorders apart in early childhood. However, the features of the two disorders differ later in life.
Early infantile epileptic encephalopathy 7
MedGen UID:
462336
Concept ID:
C3150986
Disease or Syndrome
EIEE7 is an autosomal dominant seizure disorder characterized by infantile onset of refractory seizures with resultant delayed neurologic development and persistent neurologic abnormalities (Borgatti et al., 2004). EEG initially shows a burst suppression pattern and later evolves to multifocal epileptiform activity. Brain imaging may show lesions in the basal ganglia. Seizures usually remit by age 3 or 4 years, with improvement of EEG abnormalities and possibly brain imaging abnormalities, but the severe neurologic deficits persist (summary by Weckhuysen et al., 2012). Mutation in the KCNQ2 gene can also cause benign familial neonatal seizures-1 (BFNS1; 121200).
Chromosome 7q11.23 deletion syndrome, distal, 1.2-mb
MedGen UID:
462349
Concept ID:
C3150999
Disease or Syndrome
Hemizygous 1.2-Mb deletion of the distal region of chromosome 7q11.23 is associated with increased risk for epilepsy, learning difficulties, intellectual disabilities, and/or neurobehavioral abnormalities (Ramocki et al., 2010).
Hemorrhagic destruction of the brain, subependymal calcification, and cataracts
MedGen UID:
462350
Concept ID:
C3151000
Disease or Syndrome
HDBSCC is an autosomal recessive disorder with a distinctive phenotype comprising hemorrhagic destruction of the brain, subependymal calcification, and congenital cataracts. Affected individuals have a catastrophic neurologic clinical course resulting in death in infancy (summary by Akawi et al., 2013).
Chromosome 1p32-p31 deletion syndrome
MedGen UID:
462386
Concept ID:
C3151036
Disease or Syndrome
Cerebral palsy, spastic quadriplegic, 4
MedGen UID:
462406
Concept ID:
C3151056
Disease or Syndrome
Spastic paraplegia-51 is an autosomal recessive neurodevelopmental disorder characterized by neonatal hypotonia that progresses to hypertonia and spasticity and severe mental retardation with poor or absent speech development (summary by Moreno-De-Luca et al., 2011).
Infections, recurrent, with encephalopathy, hepatic dysfunction, and cardiovascular malformations
MedGen UID:
462412
Concept ID:
C3151062
Disease or Syndrome
Pontocerebellar hypoplasia type 2D
MedGen UID:
462490
Concept ID:
C3151140
Disease or Syndrome
PCH2D is an autosomal recessive disorder characterized by progressive microcephaly, postnatal onset of progressive atrophy of the cerebrum and cerebellum, profound mental retardation, spasticity, and variable seizures (summary by Ben-Zeev et al., 2003). For a general phenotypic description and a discussion of genetic heterogeneity of pontocerebellar hypoplasia type 2, see PCH2A (277470).
Megalencephalic leukoencephalopathy with subcortical cysts 2a
MedGen UID:
462705
Concept ID:
C3151355
Disease or Syndrome
The classic phenotype of megalencephalic leukoencephalopathy with subcortical cysts (MLC) is characterized by early-onset macrocephaly, often in combination with mild gross motor developmental delay and seizures; gradual onset of ataxia, spasticity, and sometimes extrapyramidal findings; and usually late onset of mild mental deterioration. Macrocephaly, observed in all individuals, may be present at birth but more frequently develops during the first year of life. The degree of macrocephaly is variable and can be as great as 4 to 6 SD above the mean in some individuals. After the first year of life, head growth rate normalizes and growth follows a line parallel to the 98th percentile, usually several centimeters above it. Almost all individuals have epilepsy from an early age. Initial mental and motor development is normal in most cases. Walking is often unstable, followed by ataxia of the trunk and extremities, then minor signs of pyramidal dysfunction and brisk deep-tendon stretch reflexes. Mental deterioration is late and mild. Severity ranges from independent walking for a few years only to independent walking in the fifth decade. Some individuals have died in their teens or twenties; others are alive in their forties. An atypical improving phenotype has a similar initial presentation without mental or motor regression, followed by an improving clinical course: motor and cognitive functions improve or normalize; macrocephaly usually persists, but some children become normocephalic; hypotonia and clumsiness may persist in some or neurologic examination may become normal. Some have intellectual disability that is stable with or without autism.
Lissencephaly 4
MedGen UID:
462811
Concept ID:
C3151461
Disease or Syndrome
Lissencephaly-4 is an autosomal recessive neurodevelopmental disorder characterized by lissencephaly, severe brain atrophy, extreme microcephaly (head circumference of more than 10 standard deviations (SD) below the mean), and profound mental retardation. It has also been referred to as 'microlissencephaly' (summary by Bakircioglu et al., 2011 and Alkuraya et al., 2011). For a general phenotypic description and a discussion of genetic heterogeneity of lissencephaly, see LIS1 (607432).
Mitochondrial DNA depletion syndrome 9 (encephalomyopathic with methylmalonic aciduria)
MedGen UID:
462826
Concept ID:
C3151476
Disease or Syndrome
Mitochondrial DNA depletion syndrome-9 is a severe autosomal recessive disorder characterized by infantile onset of hypotonia, lactic acidosis, severe psychomotor retardation, progressive neurologic deterioration, and excretion of methylmalonic acid. Some patients die in early infancy (summary by Rouzier et al., 2010). For a discussion of genetic heterogeneity of mtDNA depletion syndromes, see MTDPS1 (603041).
Mitochondrial DNA-depletion syndrome 3, hepatocerebral
MedGen UID:
462863
Concept ID:
C3151513
Disease or Syndrome
The two forms of deoxyguanosine kinase (DGUOK) deficiency are a hepatocerebral mitochondrial DNA depletion syndrome (multisystem disease in neonates) and isolated hepatic disease later in infancy or childhood. The majority of affected individuals have the multisystem illness with hepatic disease (cholestasis) and neurologic dysfunction evident within weeks of birth. They subsequently manifest severe hypotonia, developmental regression, and typical rotary nystagmus that evolves into opsoclonus. Those with isolated liver disease may also have renal involvement and some later develop mild hypotonia. Progressive hepatic disease is the most common cause of death in both forms.
Combined oxidative phosphorylation deficiency 6
MedGen UID:
463103
Concept ID:
C3151753
Disease or Syndrome
NSDHL-Related Disorders
MedGen UID:
463131
Concept ID:
C3151781
Disease or Syndrome
CK syndrome (CKS) is an X-linked recessive disorder characterized by mild to severe cognitive impairment, seizures, microcephaly, cerebral cortical malformations, dysmorphic facial features, and thin body habitus. It is named after the first identified patient (summary by McLarren et al., 2010). CHILD syndrome (308050) is an allelic disorder with a different phenotype.
Moyamoya disease 4 with short stature, hypergonadotropic hypogonadism, and facial dysmorphism
MedGen UID:
463207
Concept ID:
C3151857
Disease or Syndrome
This multisystem disorder is characterized by moyamoya disease, short stature, hypergonadotropic hypogonadism, and facial dysmorphism. Other variable features include dilated cardiomyopathy, premature graying of the hair, and early-onset cataracts. Moyamoya disease is a progressive cerebrovascular disorder characterized by stenosis or occlusion of the internal carotid arteries and the main branches, leading to the development of small collateral vessels (moyamoya vessels) at the base of the brain. Affected individuals can develop acute neurologic events due to stroke-like episodes (summary by Miskinyte et al., 2011). For a general phenotypic description and a discussion of genetic heterogeneity of moyamoya disease, see MYMY1 (252350).
D-2-hydroxyglutaric aciduria 1
MedGen UID:
463405
Concept ID:
C3152055
Disease or Syndrome
D-2-hydroxyglutaric aciduria is a neurometabolic disorder first described by Chalmers et al. (1980). Clinical symptoms include developmental delay, epilepsy, hypotonia, and dysmorphic features. Mild and severe phenotypes were characterized (van der Knaap et al., 1999). The severe phenotype is homogeneous and is characterized by early infantile-onset epileptic encephalopathy and, often, cardiomyopathy. The mild phenotype has a more variable clinical presentation. Genetic Heterogeneity of D-2-Hydroxyglutaric Aciduria D-2-hydroxyglutaric aciduria-2 (D2HGA2; 613657) is caused by heterozygous mutation in the mitochondrial isocitrate dehydrogenase-2 gene (IDH2; 147650) on chromosome 15q26.
Niemann-Pick disease type C1
MedGen UID:
465922
Concept ID:
C3179455
Disease or Syndrome
Niemann-Pick disease type C (NPC) is a lipid storage disease that can present in infants, children, or adults. Neonates can present with ascites and severe liver disease from infiltration of the liver and/or respiratory failure from infiltration of the lungs. Other infants, without liver or pulmonary disease, have hypotonia and developmental delay. The classic presentation occurs in mid-to-late childhood with the insidious onset of ataxia, vertical supranuclear gaze palsy (VSGP), and dementia. Dystonia and seizures are common. Dysarthria and dysphagia eventually become disabling, making oral feeding impossible; death usually occurs in the late second or third decade from aspiration pneumonia. Adults are more likely to present with dementia or psychiatric symptoms.
X-Linked mental retardation 90
MedGen UID:
477074
Concept ID:
C3275443
Disease or Syndrome
X-Linked Mental Retardation 88
MedGen UID:
477075
Concept ID:
C3275444
Disease or Syndrome
Syndromic mental retardation, Nascimento type, X-linked
MedGen UID:
477095
Concept ID:
C3275464
Disease or Syndrome
The Nascimento type of X-linked syndromic mental retardation is characterized by dysmorphic features, including large head, synophrys, prominent supraorbital ridges, almond-shaped and deep-set eyes, large ears, wide mouth, myxedematous appearance, hirsutism, abnormal hair whorls, micropenis, and onychodystrophy. Female carriers have normal cognition, but may show subtle facial features (summary by Budny et al., 2010).
Mental retardation, X-linked, syndromic, chudley-schwartz type
MedGen UID:
477102
Concept ID:
C3275471
Disease or Syndrome
Cerebral-cerebellar-coloboma syndrome, X-linked
MedGen UID:
477118
Concept ID:
C3275487
Disease or Syndrome
Kabuki syndrome 2
MedGen UID:
477126
Concept ID:
C3275495
Disease or Syndrome
Kabuki syndrome is a congenital mental retardation syndrome with additional features, including postnatal dwarfism, a peculiar facies characterized by long palpebral fissures with eversion of the lateral third of the lower eyelids (reminiscent of the make-up of actors of Kabuki, a Japanese traditional theatrical form), a broad and depressed nasal tip, large prominent earlobes, a cleft or high-arched palate, scoliosis, short fifth finger, persistence of fingerpads, radiographic abnormalities of the vertebrae, hands, and hip joints, and recurrent otitis media in infancy (Niikawa et al., 1981). For a discussion of genetic heterogeneity of Kabuki syndrome, see KABUK1 (147920).
Cortical dysplasia, complex, with other brain malformations 1
MedGen UID:
481300
Concept ID:
C3279670
Disease or Syndrome
Complex cortical dysplasia with other brain malformations (CDCBM) is a disorder of aberrant neuronal migration and disturbed axonal guidance. Affected individuals have mild to severe mental retardation, strabismus, axial hypotonia, and spasticity. Brain imaging shows variable malformations of cortical development, including polymicrogyria, gyral disorganization, and fusion of the basal ganglia, as well as thin corpus callosum, hypoplastic brainstem, and dysplastic cerebellar vermis. Extraocular muscles are not involved (summary by Poirier et al., 2010). Mutation in the TUBB3 gene can also cause congenital fibrosis of extraocular muscles-3A (CFEOM3A; 600638), a milder and somewhat different neurologic phenotype. Genetic Heterogeneity of Complex Cortical Dysplasia With Other Brain Malformations See also CDCBM2 (615282), caused by mutation in the KIF5C gene (604593) on chromosome 2q23; CDCBM3 (615411), caused by mutation in the KIF2A gene (602591) on chromosome 5q12; CDCBM4 (615412), caused by mutation in the TUBG1 gene (191135) on chromosome 17q21; CDCBM5 (615763), caused by mutation in the TUBB2A gene (615101) on chromosome 6p25; and CDCBM6 (615771), caused by mutation in the TUBB gene (191130) on chromosome 6p21.
Nuclearly-encoded mitochondrial complex V (ATP synthase) deficiency 2
MedGen UID:
481329
Concept ID:
C3279699
Disease or Syndrome
N-acetylaspartate deficiency
MedGen UID:
481346
Concept ID:
C3279716
Disease or Syndrome
Multiple congenital anomalies-hypotonia-seizures syndrome 1
MedGen UID:
481405
Concept ID:
C3279775
Disease or Syndrome
Multiple congenital anomalies-hypotonia-seizures syndrome is an autosomal recessive disorder characterized by neonatal hypotonia, lack of psychomotor development, seizures, dysmorphic features, and variable congenital anomalies involving the cardiac, urinary, and gastrointestinal systems. Most affected individuals die before 3 years of age (summary by Maydan et al., 2011). Genetic Heterogeneity of Multiple Congenital Anomalies-Hypotonia-Seizures Syndrome MCAHS2 (300868) is caused by mutation in the PIGA gene (311770) on chromosome Xp22, and MCAHS3 (615398) is caused by mutation in the PIGT gene (610272) on chromosome 20q13.
Mental retardation, autosomal recessive 15
MedGen UID:
481757
Concept ID:
C3280127
Disease or Syndrome
Hyperphosphatasia with mental retardation syndrome 3
MedGen UID:
481783
Concept ID:
C3280153
Disease or Syndrome
Hyperphosphatasia with mental retardation syndrome-3 is an autosomal recessive disorder usually characterized by severe mental retardation, hypotonia with very poor motor development, poor speech, and increased serum alkaline phosphatase (summary by Hansen et al., 2013). However, the severity of the disorder can also vary to include milder intellectual disability (Krawitz et al., 2013). For a discussion of genetic heterogeneity of HPMRS, see HPMRS1 (239300).
Encephalopathy, acute, infection-induced, 4, susceptibility to
MedGen UID:
481790
Concept ID:
C3280160
Finding
Acute encephalopathy is a severe neurologic complication of an infection that usually occurs in children. It is characterized by a high-grade fever accompanied within 12 to 48 hours by febrile convulsions, often leading to coma, multiple-organ failure, brain edema, and high morbidity and mortality. The infections are usually viral, particularly influenza, although other viruses and even mycoplasma have been found to cause the disorder (summary by Chen et al., 2005; Shinohara et al., 2011). For a discussion of genetic heterogeneity of susceptibility to acute infection-induced encephalopathy, see 610551.
Adams-Oliver syndrome 2
MedGen UID:
481812
Concept ID:
C3280182
Disease or Syndrome
Adams-Oliver syndrome-2 is an autosomal recessive multiple congenital anomaly syndrome characterized by aplasia cutis congenita and terminal transverse limb defects, in association with variable involvement of the brain, eyes, and cardiovascular systems (summary by Shaheen et al., 2011). For a discussion of genetic heterogeneity of Adams-Oliver syndrome, see AOS1 (100300).
Warburg micro syndrome 3
MedGen UID:
481833
Concept ID:
C3280203
Disease or Syndrome
AMELOGENESIS IMPERFECTA AND GINGIVAL FIBROMATOSIS SYNDROME
MedGen UID:
481906
Concept ID:
C3280276
Disease or Syndrome
Amelogenesis imperfecta and gingival fibromatosis syndrome is an autosomal recessive condition characterized by mild gingival fibromatosis and dental anomalies, including hypoplastic amelogenesis imperfecta, intrapulpal calcifications, delay of tooth eruption, hypodontia/oligodontia, pericoronal radiolucencies, and unerupted teeth (Martelli-Junior et al., 2008).
Microcephaly-capillary malformation syndrome
MedGen UID:
481926
Concept ID:
C3280296
Disease or Syndrome
The microcephaly-capillary malformation (MIC-CAP) syndrome is characterized by microcephaly, generalized cutaneous capillary malformations (ranging from a few to hundreds of oval/circular macules or patches varying in size from 1-2 mm to several cm), hypoplastic distal phalanges of the hands and/or feet, intractable epilepsy, and profound developmental delay. Seizures, which can include focal, tonic, complex partial, and infantile spasms, seem to stabilize after the first two years of life. Myoclonus of the limbs and eyelids is common; other abnormal movements (dyskinetic, choreiform) may be seen. Minimal developmental progress is made after birth. To date the diagnosis has been confirmed in 12 affected individuals (including 2 sibs).
Multiple mitochondrial dysfunctions syndrome 2
MedGen UID:
482008
Concept ID:
C3280378
Disease or Syndrome
Multiple mitochondrial dysfunctions syndrome is characterized by impairment of cellular structures called mitochondria, which are the energy-producing centers of cells. While certain mitochondrial disorders are caused by impairment of a single stage of energy production, individuals with multiple mitochondrial dysfunctions syndrome have reduced function of more than one stage. The signs and symptoms of this severe condition begin early in life, and affected individuals usually do not live past infancy. Affected infants typically have severe brain dysfunction (encephalopathy), which can contribute to weak muscle tone (hypotonia), seizures, and delayed development of mental and movement abilities (psychomotor delay). These infants often have difficulty growing and gaining weight at the expected rate (failure to thrive). Most affected babies have a buildup of a chemical called lactic acid in the body (lactic acidosis), which can be life-threatening. They may also have high levels of a molecule called glycine (hyperglycinemia) or elevated levels of sugar (hyperglycemia) in the blood. Some babies with multiple mitochondrial dysfunctions syndrome have high blood pressure in the blood vessels that connect to the lungs (pulmonary hypertension) or weakening of the heart muscle (cardiomyopathy).
Hypermethioninemia due to adenosine kinase deficiency
MedGen UID:
482011
Concept ID:
C3280381
Disease or Syndrome
Hypermethioninemia due to adenosine kinase deficiency is an autosomal recessive inborn error of metabolism characterized by global developmental delay, early-onset seizures, mild dysmorphic features, and characteristic biochemical anomalies, including persistent hypermethioninemia with increased levels of S-adenosylmethionine (AdoMet) and S-adenosylhomocysteine (AdoHcy); homocysteine is typically normal (summary by Bjursell et al., 2011).
Spinocerebellar ataxia, autosomal recessive 12
MedGen UID:
482082
Concept ID:
C3280452
Disease or Syndrome
Autosomal recessive spinocerebellar ataxia-12 is a neurologic disorder characterized by onset of generalized seizures in infancy, delayed psychomotor development with mental retardation, and cerebellar ataxia. Some patients may also show spasticity (summary by Mallaret et al., 2014).
Myopathy, areflexia, respiratory distress, and dysphagia, early-onset
MedGen UID:
482309
Concept ID:
C3280679
Disease or Syndrome
This disorder represents a congenital myopathy characterized by proximal and generalized muscle weakness, respiratory difficulties, joint contractures, and scoliosis. More variable features include cleft palate and feeding difficulties. There is variable severity: some patients become ventilator-dependent, never achieve walking, and die in childhood, whereas others have a longer and more favorable course (summary by Logan et al., 2011 and Boyden et al., 2012).
Epilepsy, familial temporal lobe, 5
MedGen UID:
482360
Concept ID:
C3280730
Disease or Syndrome
THIAMINE METABOLISM DYSFUNCTION SYNDROME 5 (EPISODIC ENCEPHALOPATHY TYPE)
MedGen UID:
482496
Concept ID:
C3280866
Disease or Syndrome
Episodic encephalopathy due to thiamine pyrophosphokinase deficiency is an autosomal recessive metabolic disorder due to an inborn error of thiamine metabolism. The phenotype is highly variable, but in general, affected individuals have onset in early childhood of acute encephalopathic episodes associated with increased serum and CSF lactate. These episodes result in progressive neurologic dysfunction manifest as gait disturbances, ataxia, dystonia, and spasticity, which in some cases may result in loss of ability to walk. Cognitive function is usually preserved, although mildly delayed development has been reported. These episodes are usually associated with infection and metabolic decompensation. Some patients may have recovery of some neurologic deficits (summary by Mayr et al., 2011). For a discussion of genetic heterogeneity of disorders due to thiamine metabolism dysfunction, see THMD1 (249270).
Pyruvate dehydrogenase lipoic acid synthetase deficiency
MedGen UID:
482517
Concept ID:
C3280887
Disease or Syndrome
Pyruvate dehydrogenase lipoic acid synthetase deficiency is an autosomal recessive disorder of mitochondrial metabolism characterized by early-onset lactic acidosis, severe encephalomyopathy, and a pyruvate oxidation defect (Mayr et al., 2011).
Congenital cataracts, hearing loss, and neurodegeneration
MedGen UID:
482595
Concept ID:
C3280965
Disease or Syndrome
Congenital cataracts, hearing loss, and neurodegeneration (CCHLND) is an autosomal recessive disorder characterized by congenital cataracts, severe psychomotor retardation, and hearing loss associated with decreased serum ceruloplasmin and copper. Brain MRI shows cerebral and cerebellar atrophy and hypomyelination (summary by Huppke et al., 2012).
Porencephaly 2
MedGen UID:
482600
Concept ID:
C3280970
Disease or Syndrome
Porencephaly is a neurologic disorder characterized by fluid-filled cysts or cavities in the brain and is thought to result from disturbed vascular supply leading to cerebral degeneration. Affected individuals typically have hemiplegia, seizures, and intellectual disability, although the severity is variable (summary by Yoneda et al., 2012). For a discussion of genetic heterogeneity of porencephaly, see POREN1 (175780).
Psychomotor retardation, epilepsy, and craniofacial dysmorphism
MedGen UID:
482685
Concept ID:
C3281055
Disease or Syndrome
Encephalomyopathy, mitochondrial, due to voltage-dependent anion channel deficiency
MedGen UID:
482736
Concept ID:
C3281106
Disease or Syndrome
Chromosome 17q12 duplication syndrome
MedGen UID:
482767
Concept ID:
C3281137
Disease or Syndrome
Chromosome 17q12 deletion syndrome
MedGen UID:
482768
Concept ID:
C3281138
Disease or Syndrome
Infantile cerebellar-retinal degeneration
MedGen UID:
482822
Concept ID:
C3281192
Disease or Syndrome
Infantile cerebellar-retinal degeneration is a severe autosomal recessive neurodegenerative disorder characterized by onset between ages 2 and 6 months of truncal hypotonia, athetosis, seizures, and ophthalmologic abnormalities, particularly optic atrophy and retinal degeneration. Affected individuals show profound psychomotor retardation, with only some achieving rolling, sitting, or recognition of family. Brain MRI shows progressive cerebral and cerebellar degeneration (summary by Spiegel et al., 2012).
Leukoencephalopathy, brain calcifications, and cysts
MedGen UID:
482830
Concept ID:
C3281200
Disease or Syndrome
Leukoencephalopathy, brain calcifications, and cysts (LCC), also known as Labrune syndrome, is characterized by a constellation of features restricted to the central nervous system, including leukoencephalopathy, brain calcifications, and cysts, resulting in spasticity, dystonia, seizures, and cognitive decline (summary by Labrune et al., 1996). See also cerebroretinal microangiopathy with calcifications and cysts (CRMCC; 612199), an autosomal recessive disorder caused by mutation in the CTC1 gene (613129) that shows phenotypic similarities to Labrune syndrome. CRMCC includes the neurologic findings of intracranial calcifications, leukodystrophy, and brain cysts, but also includes retinal vascular abnormalities and other systemic manifestations, such as osteopenia with poor bone healing, a high risk of gastrointestinal bleeding, hair, skin, and nail changes, and anemia and thrombocytopenia. Although Coats plus syndrome and Labrune syndrome were initially thought to be manifestations of the same disorder, namely CRMCC, molecular evidence has excluded mutations in the CTC1 gene in patients with Labrune syndrome, suggesting that the 2 disorders are not allelic (Anderson et al., 2012; Polvi et al., 2012).
Mental retardation, autosomal dominant 13
MedGen UID:
482832
Concept ID:
C3281202
Disease or Syndrome
MRD13 is an autosomal dominant form of mental retardation associated with variable neuronal migration defects resulting in cortical malformations. More variable features include early-onset seizures and mild dysmorphic features. Some patients may also show signs of peripheral neuropathy, such as abnormal gait, hyporeflexia, and foot deformities (summary by Willemsen et al., 2012 and Poirier et al., 2013).
Baraitser-Winter Syndrome 2
MedGen UID:
482865
Concept ID:
C3281235
Disease or Syndrome
Baraitser-Winter syndrome is a condition that affects the development of many parts of the body, particularly the face and the brain. An unusual facial appearance is the most common characteristic of Baraitser-Winter syndrome. Distinctive facial features can include widely spaced eyes (hypertelorism), large eyelid openings, droopy eyelids (ptosis), high-arched eyebrows, a broad nasal bridge and tip of the nose, a long space between the nose and upper lip (philtrum), full cheeks, and a pointed chin. Structural brain abnormalities are also present in most people with Baraitser-Winter syndrome. These abnormalities are related to impaired neuronal migration, a process by which nerve cells (neurons) move to their proper positions in the developing brain. The most frequent brain abnormality associated with Baraitser-Winter syndrome is pachygyria, which is an area of the brain that has an abnormally smooth surface with fewer folds and grooves. Less commonly, affected individuals have lissencephaly, which is similar to pachygyria but involves the entire brain surface. These structural changes can cause mild to severe intellectual disability, developmental delay, and seizures. Other features of Baraitser-Winter syndrome can include short stature, ear abnormalities and hearing loss, heart defects, presence of an extra (duplicated) thumb, and abnormalities of the kidneys and urinary system. Some affected individuals have limited movement of large joints, such as the elbows and knees, which may be present at birth or develop over time. Rarely, people with Baraitser-Winter syndrome have involuntary muscle tensing (dystonia).
Epileptic encephalopathy, early infantile, 1
MedGen UID:
483052
Concept ID:
C3463992
Disease or Syndrome
Early infantile epileptic encephalopathy is a severe form of epilepsy first reported by Ohtahara et al. (1976). It is characterized by frequent tonic seizures or spasms beginning in infancy with a specific EEG finding of suppression-burst patterns, characterized by high-voltage bursts alternating with almost flat suppression phases. Approximately 75% of EIEE patients progress to 'West syndrome,' which is characterized by tonic spasms with clustering, arrest of psychomotor development, and hypsarrhythmia on EEG (Kato et al., 2007). Deprez et al. (2009) reviewed the genetics of epilepsy syndromes starting in the first year of life and included a diagnostic algorithm. EIEE1 is part of a phenotypic spectrum of disorders caused by mutation in the ARX gene comprising a nearly continuous series of developmental disorders ranging from lissencephaly (LISX2; 300215) to Proud syndrome (300004) to infantile spasms without brain malformations (EIEE1) to syndromic (309510) and nonsyndromic (300419) mental retardation. Although males with ARX mutations are often more severely affected, female mutation carriers may also be affected (Kato et al., 2004; Wallerstein et al., 2008). Genetic Heterogeneity of Early Infantile Epileptic Encephalopathy EIEE is a genetically heterogeneous disorder. See EIEE2 (300672), caused by mutation in the CDKL5 gene (300203); EIEE3 (609304), caused by mutation in the SLC25A22 gene (609302); EIEE4 (612164), caused by mutation in the STXBP1 gene (602926); EIEE5 (613477), caused by mutation in the SPTAN1 gene (182810); EIEE6 (607208), also known as Dravet syndrome, caused by mutation in the SCN1A gene (182389); EIEE7 (613720), caused by mutation in the KCNQ2 gene (602235); EIEE8 (300607), caused by mutation in the ARHGEF9 gene (300429); EIEE9 (300088), caused by mutation in the PCDH19 gene (300460); EIEE10 (613402), caused by mutation in the PNKP gene (605610); EIEE11 (613721), caused by mutation in the SCN2A gene (182390); EIEE12 (613722), caused by mutation in the PLCB1 gene (607120); EIEE13 (614558), caused by mutation in the SCN8A gene (600702); EIEE14 (614959), caused by mutation in the KCNT1 gene (608167); EIEE15 (615006), caused by mutation in the ST3GAL3 gene (606494); EIEE16 (615338), caused by mutation in the TBC1D24 gene (613577); EIEE17 (615473), caused by mutation in the GNAO1 gene (139311); EIEE18 (615476), caused by mutation in the SZT2 gene (615463); EIEE19 (615744), caused by mutation in the GABRA1 gene (137160); EIEE20 (300868), caused by mutation in the PIGA gene (311770); EIEE21 (615833), caused by mutation in the NECAP1 gene (611623); EIEE22 (300896), caused by mutation in the SLC35A2 gene (314375); EIEE23 (615859), caused by mutation in the DOCK7 gene (615730); EIEE24 (615871), caused by mutation in the HCN1 gene (602780); EIEE25 (615905), caused by mutation in the SLC13A5 gene (608305); EIEE26 (616056), caused by mutation in the KCNB1 gene (600397); EIEE27 (616139), caused by mutation in the GRIN2B gene (138252); EIEE28 (616211), caused by mutation in the WWOX gene (605131); EIEE29 (616339), caused by mutation in the AARS gene (601065); EIEE30 (616341), caused by mutation in the SIK1 gene (605705); EIEE31 (616346), caused by mutation in the DNM1 gene (602377); EIEE32 (616366), caused by mutation in the KCNA2 gene (176262); and EIEE33 (616409), caused by mutation in the EEF1A2 gene (602959). The phenotype is also observed in other genetic disorders, including GLUT1 deficiency syndrome (606777); glycine encephalopathy (605899); Aicardi-Goutieres syndrome (225750); and in males with MECP2 mutations (300673), among others. For associations pending confirmation, see MOLECULAR GENETICS.
Band-like calcification with simplified gyration and polymicrogyria
MedGen UID:
483678
Concept ID:
C3489725
Disease or Syndrome
Band-like calcification with simplified gyration and polymicrogyria (BLCPMG) is an autosomal recessive neurologic disorder with characteristic clinical and neuroradiologic features that mimic intrauterine TORCH infection in the absence of evidence of infection. The disorder has sometimes been referred to as pseudo-TORCH syndrome. Affected individuals have congenital microcephaly, intracranial calcifications, and severe developmental delay (Reardon et al., 1994; O'Driscoll et al., 2010). Crow et al. (2000, 2003) called attention to the phenotypic overlap of pseudo-TORCH syndrome and Aicardi-Goutieres syndrome (AGS; 225750), and even suggested that some cases may represent the same disorder. Congenital microcephaly, thrombocytopenia, hepatic dysfunction, and hepatosplenomegaly are usually associated with pseudo-TORCH syndrome and not with AGS, but some patients with AGS have shown these features.
Deficiency of aminoacyl-histidine dipeptidase
MedGen UID:
501203
Concept ID:
C3495555
Disease or Syndrome
Peroxisome biogenesis disorder 7A
MedGen UID:
761334
Concept ID:
C3539168
Disease or Syndrome
Zellweger syndrome (ZS) is an autosomal recessive multiple congenital anomaly syndrome resulting from disordered peroxisome biogenesis. Affected children present in the newborn period with profound hypotonia, seizures, and inability to feed. Characteristic craniofacial anomalies, eye abnormalities, neuronal migration defects, hepatomegaly, and chondrodysplasia punctata are present. Children with this condition do not show any significant development and usually die in the first year of life (summary by Steinberg et al., 2006). For a complete phenotypic description and a discussion of genetic heterogeneity of Zellweger syndrome, see 214100. Individuals with PBDs of complementation group 8 (CG8, equivalent to CGA) have mutations in the PEX26 gene. For information on the history of PBD complementation groups, see 214100.
Pontine tegmental cap dysplasia
MedGen UID:
762040
Concept ID:
C3541340
Disease or Syndrome
Pontine tegmental cap dysplasia (PTCD) refers to a neurologic condition characterized by a distinct pattern of hindbrain malformations apparent on brain imaging. The abnormalities affect the pons, medulla, and cerebellum. In neuroradiologic studies, the ventral side of the pons is flattened, whereas there is vaulting ('capping') of the dorsal pontine border into the fourth ventricle. Affected individuals show a variety of neurologic deficits, most commonly sensorineural deafness, impaired cranial nerve function, and variable psychomotor retardation (summary by Barth et al., 2007).
Nephronophthisis 15
MedGen UID:
762112
Concept ID:
C3541853
Disease or Syndrome
Nephronophthisis is a disorder that affects the kidneys. It is characterized by inflammation and scarring (fibrosis) that impairs kidney function. These abnormalities lead to increased urine production (polyuria), excessive thirst (polydipsia), general weakness, and extreme tiredness (fatigue). In addition, affected individuals develop fluid-filled cysts in the kidneys, usually in an area known as the corticomedullary region. Another feature of nephronophthisis is a shortage of red blood cells, a condition known as anemia. Nephronophthisis eventually leads to end-stage renal disease (ESRD), a life-threatening failure of kidney function that occurs when the kidneys are no longer able to filter fluids and waste products from the body effectively. Nephronophthisis can be classified by the approximate age at which ESRD begins: around age 1 (infantile), around age 13 (juvenile), and around age 19 (adolescent). About 85 percent of all cases of nephronophthisis are isolated, which means they occur without other signs and symptoms. Some people with nephronophthisis have additional features, which can include liver fibrosis, heart abnormalities, or mirror image reversal of the position of one or more organs inside the body (situs inversus). Nephronophthisis can occur as part of separate syndromes that affect other areas of the body; these are often referred to as nephronophthisis-associated ciliopathies. For example, Senior-Løken syndrome is characterized by the combination of nephronophthisis and a breakdown of the light-sensitive tissue at the back of the eye (retinal degeneration); Joubert syndrome affects many parts of the body, causing neurological problems and other features, which can include nephronophthisis.
Spastic paraplegia 49, autosomal recessive
MedGen UID:
762260
Concept ID:
C3542549
Disease or Syndrome
SPG49 is an autosomal recessive complicated form of spastic paraplegia, a neurodegenerative disorder of the corticospinal tracts. It is characterized by delayed psychomotor development, mental retardation, and onset of spastic paraplegia in the first decade. Affected individuals also have dysmorphic features, thin corpus callosum on brain imaging, and episodes of central apnea, which may be fatal (summary by Oz-Levi et al., 2012). For a general phenotypic description and a discussion of genetic heterogeneity of autosomal recessive spastic paraplegia, see 270800.
Epsilon-trimethyllysine hydroxylase deficiency
MedGen UID:
763789
Concept ID:
C3550875
Disease or Syndrome
Autism, the prototypic pervasive developmental disorder (PDD), is usually apparent by 3 years of age. It is characterized by a triad of limited or absent verbal communication, a lack of reciprocal social interaction or responsiveness, and restricted, stereotypic, and ritualized patterns of interests and behavior (Bailey et al., 1996; Risch et al., 1999). 'Autism spectrum disorder,' sometimes referred to as ASD, is a broader phenotype encompassing the less severe disorders Asperger syndrome (see ASPG1; 608638) and pervasive developmental disorder, not otherwise specified (PDD-NOS). 'Broad autism phenotype' includes individuals with some symptoms of autism, but who do not meet the full criteria for autism or other disorders. Mental retardation coexists in approximately two-thirds of individuals with ASD, except for Asperger syndrome, in which mental retardation is conspicuously absent (Jones et al., 2008). Genetic studies in autism often include family members with these less stringent diagnoses (Schellenberg et al., 2006). For a discussion of heterogeneity of autism, see 209850.
Cornelia de Lange syndrome 5
MedGen UID:
763817
Concept ID:
C3550903
Disease or Syndrome
Classic Cornelia de Lange syndrome (CdLS) is characterized by distinctive facial features, growth retardation (prenatal onset; <5th centile throughout life), hirsutism, and upper limb reduction defects that range from subtle phalangeal abnormalities to oligodactyly (missing digits). Craniofacial features include synophrys, arched eyebrows, long eyelashes, small upturned nose, small widely spaced teeth, and microcephaly. IQ ranges from below 30 to 102 (mean: 53). Many individuals demonstrate autistic and self-destructive tendencies. Frequent findings include cardiac septal defects, gastrointestinal dysfunction, hearing loss, myopia, and cryptorchidism or hypoplastic genitalia. Individuals with a milder phenotype have less severe growth, cognitive, and limb involvement, but often have facial features consistent with CdLS.
Mental retardation, X-linked, syndromic 32
MedGen UID:
763827
Concept ID:
C3550913
Disease or Syndrome
Neurodegeneration with brain iron accumulation 5
MedGen UID:
763887
Concept ID:
C3550973
Disease or Syndrome
NBIA5, sometimes referred to as 'static encephalopathy of childhood with neurodegeneration in adulthood (SENDA),' is an X-linked neurodegenerative disorder characterized by global developmental delay in early childhood that is essentially static, with slow motor and cognitive gains until adolescence or early adulthood. In young adulthood, affected individuals develop progressive dystonia, parkinsonism, extrapyramidal signs, and dementia resulting in severe disability. Brain MRI shows iron accumulation in the globus pallidus and substantia nigra. A characteristic finding is T1-weighted hyperintensity surrounding a central band of hypointensity in the substantia nigra. Cerebral and cerebellar atrophy are also observed (summary by Haack et al., 2012 and Saitsu et al., 2013). For a general phenotypic description and a discussion of genetic heterogeneity of NBIA, see NBIA1 (234200).
Congenital disorder of glycosylation type 2L
MedGen UID:
766144
Concept ID:
C3553230
Disease or Syndrome
Mental retardation, autosomal dominant 15
MedGen UID:
766162
Concept ID:
C3553248
Disease or Syndrome
Mental retardation, autosomal dominant 16
MedGen UID:
766163
Concept ID:
C3553249
Disease or Syndrome
Coenzyme Q10 deficiency, primary, 6
MedGen UID:
766263
Concept ID:
C3553349
Disease or Syndrome
Primary coenzyme Q10 deficiency-6 is an autosomal recessive disorder characterized by onset in infancy of severe progressive nephrotic syndrome resulting in end-stage renal failure and sensorineural deafness. Renal biopsy usually shows focal segmental glomerulosclerosis (FSGS). Some patients may show a favorable response to oral coenzyme Q supplementation (summary by Heeringa et al., 2011). For a general phenotypic description and a discussion of genetic heterogeneity of focal segmental glomerulosclerosis and nephrotic syndrome, see FSGS1 (603278) and NPHS1 (256300).
Pontocerebellar hypoplasia, type 1b
MedGen UID:
766363
Concept ID:
C3553449
Disease or Syndrome
EXOSC3-related pontocerebellar hypoplasia (PCH) is characterized by abnormalities in the posterior fossa and degeneration of the anterior horn cells. At birth, skeletal muscle weakness manifests as hypotonia (sometimes with congenital joint contractures) and poor feeding. In persons with prolonged survival, spasticity, dystonia, and seizures become evident. Within the first year of life respiratory insufficiency and swallowing difficulties are common. Intellectual disability is severe. Life expectancy ranges from a few weeks to adolescence. To date, 51 individuals with PCH from 36 families with mutation of EXOSC3 have been described.
Combined oxidative phosphorylation deficiency 10
MedGen UID:
766443
Concept ID:
C3553529
Disease or Syndrome
COXPD10 is an autosomal recessive disorder resulting in variable defects of mitochondrial oxidative respiration. Affected individuals present in infancy with hypertrophic cardiomyopathy and lactic acidosis. The severity is variable, but can be fatal in the most severe cases (summary by Ghezzi et al., 2012). For a discussion of genetic heterogeneity of combined oxidative phosphorylation deficiency, see COXPD1 (609060).
Congenital disorder of glycosylation type 2k
MedGen UID:
766485
Concept ID:
C3553571
Disease or Syndrome
Congenital disorders of N-linked glycosylation (abbreviated here as CDG-N-linked), are a group of disorders of N-linked oligosaccharides caused by deficiency in 42 different enzymes in the N-linked synthetic pathway. Most commonly, the disorders begin in infancy; manifestations range from severe developmental delay and hypotonia with multiple organ system involvement to hypoglycemia and protein-losing enteropathy with normal development. However, most types have been described in only a few individuals, and thus understanding of the phenotypes is limited. In PMM2-CDG (CDG-Ia), the most common type reported, the clinical presentation and course are highly variable, ranging from death in infancy to mild involvement in adults.
3-methylglutaconic aciduria with deafness, encephalopathy, and Leigh-like syndrome
MedGen UID:
766511
Concept ID:
C3553597
Disease or Syndrome
MEGDEL (3-methylglutaconic aciduria with deafness, encephalopathy and Leigh-like) syndrome is characterized in neonates by hypoglycemia and a sepsis-like clinical picture for which no infectious agent can be found. During the first year of life feeding problems, failure to thrive, and/or truncal hypotonia become evident; many infants experience (transient) liver involvement ranging from undulating transaminases to prolonged hyperbilirubinemia and near-fatal liver failure. By age two years progressive deafness, dystonia, and spasticity prevent further psychomotor development and/or result in loss of acquired skills. Affected children are completely dependent on care for all activities of daily living; speech is absent.
Mitochondrial pyruvate carrier deficiency
MedGen UID:
766521
Concept ID:
C3553607
Disease or Syndrome
Mitochondrial pyruvate carrier deficiency is an autosomal recessive metabolic disorder characterized by delayed psychomotor development and lactic acidosis with a normal lactate/pyruvate ratio resulting from impaired mitochondrial pyruvate oxidation (summary by Bricker et al., 2012).
Hyperphosphatasia with mental retardation syndrome 2
MedGen UID:
766551
Concept ID:
C3553637
Disease or Syndrome
Hyperphosphatasia with mental retardation syndrome-2 is an autosomal recessive disorder characterized by moderately to severely delayed psychomotor development, facial dysmorphism, brachytelephalangy, and increased serum alkaline phosphatase (hyperphosphatasia). Some patients may have additional features, such as cardiac septal defects or seizures (summary by Krawitz et al., 2012). For a discussion of genetic heterogeneity of hyperphosphatasia with mental retardation syndrome, see HPMRS1 (239300).
Spinocerebellar ataxia, autosomal recessive 13
MedGen UID:
766730
Concept ID:
C3553816
Disease or Syndrome
Autosomal recessive spinocerebellar ataxia-13 is an autosomal recessive neurologic disorder characterized by delayed psychomotor development beginning in infancy. Affected individuals show mild to profound mental retardation with poor or absent speech as well as gait and stance ataxia and hyperreflexia. Most individuals also have eye movement abnormalities. Brain MRI shows cerebellar atrophy and ventriculomegaly (summary by Guergueltcheva et al., 2012).
Polymicrogyria with seizures
MedGen UID:
766745
Concept ID:
C3553831
Disease or Syndrome
Seckel syndrome 7
MedGen UID:
766784
Concept ID:
C3553870
Disease or Syndrome
Peroxisome biogenesis disorder 3A
MedGen UID:
766843
Concept ID:
C3553929
Disease or Syndrome
The peroxisomal biogenesis disorder (PBD) Zellweger syndrome (ZS) is an autosomal recessive multiple congenital anomaly syndrome resulting from disordered peroxisome biogenesis. Affected children present in the newborn period with profound hypotonia, seizures, and inability to feed. Characteristic craniofacial anomalies, eye abnormalities, neuronal migration defects, hepatomegaly, and chondrodysplasia punctata are present. Children with this condition do not show any significant development and usually die in the first year of life (summary by Steinberg et al., 2006). For a complete phenotypic description and a discussion of genetic heterogeneity of Zellweger syndrome, see 214100. Individuals with PBDs of complementation group 3 (CG3) have mutations in the PEX12 gene. For information on the history of PBD complementation groups, see 214100.
Peroxisome biogenesis disorder 4A
MedGen UID:
766850
Concept ID:
C3553936
Disease or Syndrome
The peroxisomal biogenesis disorder (PBD) Zellweger syndrome (ZS) is an autosomal recessive multiple congenital anomaly syndrome. Affected children present in the newborn period with profound hypotonia, seizures, and inability to feed. Characteristic craniofacial anomalies, eye abnormalities, neuronal migration defects, hepatomegaly, and chondrodysplasia punctata are present. Children with this condition do not show any significant development and usually die in the first year of life (summary by Steinberg et al., 2006). For a complete phenotypic description and a discussion of genetic heterogeneity of Zellweger syndrome, see 214100. Individuals with PBDs of complementation group 4 (CG4, equivalent to CG6 and CGC) have mutations in the PEX6 gene. For information on the history of PBD complementation groups, see 214100.
Peroxisome biogenesis disorder 5A
MedGen UID:
766854
Concept ID:
C3553940
Disease or Syndrome
The peroxisomal biogenesis disorder (PBD) Zellweger syndrome (ZS) is an autosomal recessive multiple congenital anomaly syndrome. Affected children present in the newborn period with profound hypotonia, seizures, and inability to feed. Characteristic craniofacial anomalies, eye abnormalities, neuronal migration defects, hepatomegaly, and chondrodysplasia punctata are present. Children with this condition do not show any significant development and usually die in the first year of life (summary by Steinberg et al., 2006). For a complete phenotypic description and a discussion of genetic heterogeneity of Zellweger syndrome, see 214100. Individuals with PBDs of complementation group 5 (CG5, equivalent to CG10 and CGF) have mutations in the PEX2 gene. For information on the history of PBD complementation groups, see 214100.
Peroxisome biogenesis disorder 6A
MedGen UID:
766861
Concept ID:
C3553947
Disease or Syndrome
Zellweger syndrome (ZS) is an autosomal recessive multiple congenital anomaly syndrome resulting from disordered peroxisome biogenesis. Affected children present in the newborn period with profound hypotonia, seizures, and inability to feed. Characteristic craniofacial anomalies, eye abnormalities, neuronal migration defects, hepatomegaly, and chondrodysplasia punctata are present. Children with this condition do not show any significant development and usually die in the first year of life (summary by Steinberg et al., 2006). For a complete phenotypic description and a discussion of genetic heterogeneity of Zellweger syndrome, see 214100. Individuals with PBDs of complementation group 7 (CG7, equivalent to CGB) have mutations in the PEX10 gene. For information on the history of PBD complementation groups, see 214100.
Peroxisome biogenesis disorder 8A
MedGen UID:
766873
Concept ID:
C3553959
Disease or Syndrome
Zellweger syndrome (ZS) is an autosomal recessive multiple congenital anomaly syndrome resulting from disordered peroxisome biogenesis. Affected children present in the newborn period with profound hypotonia, seizures, and inability to feed. Characteristic craniofacial anomalies, eye abnormalities, neuronal migration defects, hepatomegaly, and chondrodysplasia punctata are present. Children with this condition do not show any significant development and usually die in the first year of life (summary by Steinberg et al., 2006). For a complete phenotypic description and a discussion of genetic heterogeneity of Zellweger syndrome, see 214100. Individuals with PBDs of complementation group 9 (CG9, equivalent to CGD) have mutations in the PEX16 gene. For information on the history of PBD complementation groups, see 214100.
Peroxisome biogenesis disorder 10A
MedGen UID:
766913
Concept ID:
C3553999
Disease or Syndrome
Zellweger syndrome (ZS) is an autosomal recessive multiple congenital anomaly syndrome resulting from disordered peroxisome biogenesis. Affected children present in the newborn period with profound hypotonia, seizures, and inability to feed. Characteristic craniofacial anomalies, eye abnormalities, neuronal migration defects, hepatomegaly, and chondrodysplasia punctata are present. Children with this condition do not show any significant development and usually die in the first year of life (summary by Steinberg et al., 2006). For a complete phenotypic description and a discussion of genetic heterogeneity of Zellweger syndrome, see 214100. Individuals with PBDs of complementation group 12 (CG12, equivalent to CGG) have mutations in the PEX3 gene. For information on the history of PBD complementation groups, see 214100.
Peroxisome biogenesis disorder 11A
MedGen UID:
766914
Concept ID:
C3554000
Disease or Syndrome
Zellweger syndrome (ZS) is an autosomal recessive multiple congenital anomaly syndrome resulting from disordered peroxisome biogenesis. Affected children present in the newborn period with profound hypotonia, seizures, and inability to feed. Characteristic craniofacial anomalies, eye abnormalities, neuronal migration defects, hepatomegaly, and chondrodysplasia punctata are present. Children with this condition do not show any significant development and usually die in the first year of life (summary by Steinberg et al., 2006). For a complete phenotypic description and a discussion of genetic heterogeneity of Zellweger syndrome, see 214100. Individuals with PBDs of complementation group 13 (CG13, equivalent to CGH) have mutations in the PEX13 gene. For information on the history of PBD complementation groups, see 214100.
Peroxisome biogenesis disorder 12A
MedGen UID:
766916
Concept ID:
C3554002
Disease or Syndrome
Zellweger syndrome (ZS) is an autosomal recessive multiple congenital anomaly syndrome resulting from disordered peroxisome biogenesis. Affected children present in the newborn period with profound hypotonia, seizures, and inability to feed. Characteristic craniofacial anomalies, eye abnormalities, neuronal migration defects, hepatomegaly, and chondrodysplasia punctata are present. Children with this condition do not show any significant development and usually die in the first year of life (summary by Steinberg et al., 2006). For a complete phenotypic description and a discussion of genetic heterogeneity of Zellweger syndrome, see 214100. Individuals with PBDs of complementation group 14 (CG14, equivalent to CGJ) have mutations in the PEX19 gene. For information on the history of PBD complementation groups, see 214100.
Peroxisome biogenesis disorder 13A
MedGen UID:
766918
Concept ID:
C3554004
Disease or Syndrome
Zellweger syndrome (ZS) is an autosomal recessive multiple congenital anomaly syndrome resulting from disordered peroxisome biogenesis. Affected children present in the newborn period with profound hypotonia, seizures, and inability to feed. Characteristic craniofacial anomalies, eye abnormalities, neuronal migration defects, hepatomegaly, and chondrodysplasia punctata are present. Children with this condition do not show any significant development and usually die in the first year of life (summary by Steinberg et al., 2006). For a complete phenotypic description and a discussion of genetic heterogeneity of Zellweger syndrome, see 214100. Individuals with PBDs of complementation group K (CGK) have mutations in the PEX14 gene. For information on the history of PBD complementation groups, see 214100.
Branched-chain ketoacid dehydrogenase kinase deficiency
MedGen UID:
766992
Concept ID:
C3554078
Disease or Syndrome
Combined oxidative phosphorylation deficiency 12
MedGen UID:
766993
Concept ID:
C3554079
Disease or Syndrome
COXPD12 is an autosomal recessive mitochondrial neurologic disorder characterized by onset in infancy of hypotonia and delayed psychomotor development, or early developmental regression, associated with T2-weighted hyperintensities in the deep cerebral white matter, brainstem, and cerebellar white matter. Serum lactate is increased due to a defect in mitochondrial respiration. There are 2 main phenotypic groups: those with a milder disease course and some recovery of skills after age 2 years, and those with a severe disease course resulting in marked disability (summary by Steenweg et al., 2012). For a discussion of genetic heterogeneity of combined oxidative phosphorylation deficiency, see COXPD1 (609060).
Combined oxidative phosphorylation deficiency 14
MedGen UID:
767082
Concept ID:
C3554168
Disease or Syndrome
COXPD14 is a severe multisystemic autosomal recessive disorder characterized by neonatal onset of global developmental delay, refractory seizures, and lactic acidosis. Biochemical studies show deficiencies of multiple mitochondrial respiratory enzymes. Neuropathologic studies in 1 patient showed laminar cortical necrosis, characteristic of Alpers syndrome (203700) (summary by Elo et al., 2012). For a discussion of genetic heterogeneity of combined oxidative phosphorylation deficiency, see COXPD1 (609060).
Combined oxidative phosphorylation deficiency 15
MedGen UID:
767096
Concept ID:
C3554182
Disease or Syndrome
Pontocerebellar hypoplasia, type 7
MedGen UID:
767140
Concept ID:
C3554226
Disease or Syndrome
Pontocerebellar hypoplasia type 7 (PCH7) is a severe neurologic condition characterized by delayed psychomotor development, hypotonia, breathing abnormalities, and gonadal abnormalities (summary by Anderson et al., 2011). For a general phenotypic description and a discussion of genetic heterogeneity of PCH, see PCH1 (607596).
Mental retardation, autosomal dominant 17
MedGen UID:
767257
Concept ID:
C3554343
Disease or Syndrome
MRD17 was reported in 2 unrelated males with the same de novo mutation in PACS1 causing mental retardation, distinct craniofacial features, and genital abnormalities (Schuurs-Hoeijmakers et al., 2012).
Epilepsy, familial adult myoclonic, 4
MedGen UID:
767474
Concept ID:
C3554560
Disease or Syndrome
Lissencephaly 5
MedGen UID:
767571
Concept ID:
C3554657
Disease or Syndrome
Lissencephaly-5 is an autosomal recessive brain malformation characterized by cobblestone changes in the cortex, more severe in the posterior region, and subcortical band heterotopia. Affected individuals have hydrocephalus, seizures, and severely delayed psychomotor development (summary by Radmanesh et al., 2013). For a general phenotypic description and a discussion of genetic heterogeneity of lissencephaly, see LIS1 (607432).
Osteosclerotic metaphyseal dysplasia
MedGen UID:
767579
Concept ID:
C3554665
Disease or Syndrome
Osteosclerotic metaphyseal dysplasia is a rare condition characterized by developmental delay, hypotonia, and distinctive radiographic changes, including osteosclerosis localized predominantly to the metaphyses of the long bones. The shafts of the long bones are osteopenic. The skull appears to be spared. Seizures and later-onset spastic paraplegia have been reported. Laboratory abnormalities include elevated alkaline phosphatase levels in some, but not all, patients. Elevated urinary pyridinoline and deoxypyridinoline levels, markers of osteoclastic activity, have also been reported (summary by Nishimura and Kozlowski, 1993 and Kasapkara et al., 2013).
Hydrocephalus, nonsyndromic, autosomal recessive 2
MedGen UID:
767605
Concept ID:
C3554691
Disease or Syndrome
Spastic paraplegia 35
MedGen UID:
777150
Concept ID:
C3668943
Disease or Syndrome
Fatty acid hydroxylase-associated neurodegeneration (FAHN) is characterized by central nervous system involvement including corticospinal tract involvement (spasticity), mixed movement disorder (ataxia/dystonia), eye findings (optic atrophy, oculomotor abnormalities) early in the disease course, and progressive intellectual impairment and seizures later in the disease course. FAHN is considered to be a subtype of neurodegeneration with brain iron accumulation (NBIA). To date, a total of 25 individuals from seven families of diverse ethnicity with FAHN have been described; much is yet to be learned about the clinical manifestations and natural history.
Limb-girdle muscular dystrophy-dystroglycanopathy, type C14
MedGen UID:
811507
Concept ID:
C3714932
Disease or Syndrome
MDDGC14 is an autosomal recessive form of muscular dystrophy characterized by onset in early childhood of mild proximal muscle weakness. Some patients may have additional features, such as mild intellectual disability or seizures. It is part of a group of similar disorders resulting from defective glycosylation of alpha-dystroglycan (DAG1; 128239), collectively known as 'dystroglycanopathies' (summary by Carss et al., 2013). For a discussion of genetic heterogeneity of muscular dystrophy-dystroglycanopathy type C, see MDDGC1 (609308).
Ceroid lipofuscinosis, neuronal, 13
MedGen UID:
811566
Concept ID:
C3715049
Disease or Syndrome
Neuronal ceroid lipofuscinosis-13 is an autosomal recessive neurodegenerative disorder characterized by adult onset of progressive cognitive decline and motor dysfunction leading to dementia and often early death. Some patients develop seizures. Neurons show abnormal accumulation of autofluorescent material (summary by Smith et al., 2013). Adult-onset neuronal ceroid lipofuscinosis is sometimes referred to as Kufs disease. For a discussion of genetic heterogeneity of neuronal ceroid lipofuscinosis (CLN), see CLN1 (256730).
CONGENITAL DISORDER OF GLYCOSYLATION, TYPE IIm
MedGen UID:
813018
Concept ID:
C3806688
Disease or Syndrome
Mental retardation, X-linked 98
MedGen UID:
813060
Concept ID:
C3806730
Disease or Syndrome
Congenital muscular dystrophy-dystroglycanopathy with brain and eye anomalies, type A12
MedGen UID:
815294
Concept ID:
C3808964
Disease or Syndrome
Congenital muscular dystrophy-dystroglycanopathy with brain and eye anomalies (type A) is an autosomal recessive disorder with congenital muscular dystrophy resulting in muscle weakness early in life and brain and eye anomalies. It is usually associated with delayed psychomotor development and shortened life expectancy. The phenotype includes the alternative clinical designations Walker-Warburg syndrome (WWS) and muscle-eye-brain disease (MEB). The disorder represents the most severe end of a phenotypic spectrum of similar disorders resulting from defective glycosylation of alpha-dystroglycan (DAG1; 128239), collectively known as dystroglycanopathies (summary by Stevens et al., 2013). For a general phenotypic description and a discussion of genetic heterogeneity of muscular dystrophy-dystroglycanopathy type A, see MDDGA1 (236670).
Cortical dysplasia, complex, with other brain malformations 2
MedGen UID:
815343
Concept ID:
C3809013
Disease or Syndrome
Congenital muscular dystrophy-dystroglycanopathy with brain and eye anomalies, type A13
MedGen UID:
815372
Concept ID:
C3809042
Disease or Syndrome
Congenital muscular dystrophy-dystroglycanopathy with brain and eye anomalies (type A) is a autosomal recessive disorder associated with severe neurologic defects and resulting in early infantile death. The phenotype includes the alternative clinical designations Walker-Warburg syndrome (WWS) and muscle-eye-brain disease (MEB). The disorder represents the most severe end of a phenotypic spectrum of similar disorders resulting from defective glycosylation of alpha-dystroglycan (DAG1; 128239), collectively known as dystroglycanopathies (summary by Buysse et al., 2013). For a general phenotypic description and a discussion of genetic heterogeneity of muscular dystrophy-dystroglycanopathy type A, see MDDGA1 (236670).
Congenital muscular dystrophy-dystroglycanopathy with mental retardation, type B14
MedGen UID:
815551
Concept ID:
C3809221
Disease or Syndrome
MDDGB14 is an autosomal recessive congenital muscular dystrophy characterized by severe muscle weakness apparent in infancy and mental retardation. Some patients may have additional features, such as microcephaly, cardiac dysfunction, seizures, or cerebellar hypoplasia. It is part of a group of similar disorders resulting from defective glycosylation of alpha-dystroglycan (DAG1; 128239), collectively known as 'dystroglycanopathies' (summary by Carss et al., 2013). For a discussion of genetic heterogeneity of congenital muscular dystrophy-dystroglycanopathy type B, see MDDGB1 (613155).
Multiple congenital anomalies-hypotonia-seizures syndrome 3
MedGen UID:
815686
Concept ID:
C3809356
Disease or Syndrome
Epilepsy, familial adult myoclonic, 5
MedGen UID:
815704
Concept ID:
C3809374
Disease or Syndrome
Familial adult myoclonic epilepsy-5 is an autosomal recessive neurologic disorder characterized by onset of seizures in adolescence, followed by the development of cortical myoclonic tremor later in life. Some patients may also have neuropsychiatric abnormalities (summary by Stogmann et al., 2013).
Cortical dysplasia, complex, with other brain malformations 3
MedGen UID:
815744
Concept ID:
C3809414
Disease or Syndrome
Cortical dysplasia, complex, with other brain malformations 4
MedGen UID:
815750
Concept ID:
C3809420
Disease or Syndrome
Infantile neuroaxonal neurodegeneration with facial dysmorphism
MedGen UID:
815784
Concept ID:
C3809454
Disease or Syndrome
Infantile hypotonia with psychomotor retardation and characteristic facies (IHPRF) is a severe autosomal recessive neurologic disorder with onset at birth or in early infancy. Affected individuals show very poor, if any, normal cognitive development. Some patients are never learn to sit or walk independently (summary by Al-Sayed et al., 2013).
Infantile liver failure syndrome 1
MedGen UID:
815852
Concept ID:
C3809522
Disease or Syndrome
Mitochondrial DNA depletion syndrome 13 (encephalomyopathic type)
MedGen UID:
815922
Concept ID:
C3809592
Disease or Syndrome
Mitochondrial DNA depletion syndrome-13 is an autosomal recessive disorder characterized by early infantile onset of encephalopathy, hypotonia, lactic acidosis, and severe global developmental delay. Cells derived from patient tissues show defects in mitochondrial oxidative phosphorylation and decreased mtDNA content (summary by Bonnen et al., 2013 and Gai et al., 2013). For a discussion of genetic heterogeneity of autosomal recessive mtDNA depletion syndromes, see MTDPS1 (603041).
Mental retardation, autosomal recessive 37
MedGen UID:
816002
Concept ID:
C3809672
Disease or Syndrome
Mental retardation, autosomal recessive 38
MedGen UID:
816083
Concept ID:
C3809753
Disease or Syndrome
Parkinson disease 19, juvenile-onset
MedGen UID:
816141
Concept ID:
C3809811
Disease or Syndrome
Parkinson disease-19 is an autosomal recessive neurodegenerative disorder characterized by onset of parkinsonism in the first or second decade. Some patients may have additional neurologic features, including mental retardation and seizures (summary by Edvardson et al., 2012 and Koroglu et al., 2013). For a phenotypic description and a discussion of genetic heterogeneity of Parkinson disease, see PD (168600).
Periventricular nodular heterotopia 6
MedGen UID:
816202
Concept ID:
C3809872
Disease or Syndrome
Prader-Willi-like syndrome
MedGen UID:
816207
Concept ID:
C3809877
Disease or Syndrome
Arthrogryposis, mental retardation, and seizures
MedGen UID:
816240
Concept ID:
C3809910
Disease or Syndrome
Asparagine synthetase deficiency
MedGen UID:
816301
Concept ID:
C3809971
Disease or Syndrome
ASNS deficiency is an autosomal recessive severe neurologic disorder characterized by microcephaly, severely delayed psychomotor development, progressive encephalopathy, cortical atrophy, and seizure or hyperekplexic activity. The disorder shows onset in utero or at birth and may result in early death (summary by Ruzzo et al., 2013).
CONGENITAL DISORDER OF GLYCOSYLATION, TYPE Iw
MedGen UID:
816392
Concept ID:
C3810062
Disease or Syndrome
Congenital disorder of glycosylation type Ix
MedGen UID:
816397
Concept ID:
C3810067
Disease or Syndrome
Mental retardation, autosomal recessive 41
MedGen UID:
816555
Concept ID:
C3810225
Disease or Syndrome
Chromosome 15q11.2 deletion syndrome
MedGen UID:
816588
Concept ID:
C3810258
Disease or Syndrome
A heterozygous deletion of chromosome 15q11.2 may increase the susceptibility to neuropsychiatric or neurodevelopmental problems, including delayed psychomotor development, speech delay, autism spectrum disorder, attention deficit-hyperactivity disorder, obsessive-compulsive disorder, and possibly seizures (summary by Doornbos et al., 2009 and Burnside et al., 2011). See also chromosome 15q11.2 duplication syndrome (608636).
Warburg micro syndrome 4
MedGen UID:
816595
Concept ID:
C3810265
Disease or Syndrome
Chromosome 5q12 deletion syndrome
MedGen UID:
816612
Concept ID:
C3810282
Disease or Syndrome
Spinocerebellar ataxia, autosomal recessive 15
MedGen UID:
816656
Concept ID:
C3810326
Disease or Syndrome
Moyamoya disease 6 with achalasia
MedGen UID:
816733
Concept ID:
C3810403
Disease or Syndrome
Moyamoya disease-6 with achalasia is an autosomal recessive disorder characterized by onset of severe achalasia in infancy or early childhood. Most patients develop ischemic strokes and show brain imaging consistent with moyamoya disease or intracranial angiopathy. More variable vascular features include hypertension and Raynaud phenomenon (summary by Herve et al., 2014). For a general phenotypic description and a discussion of genetic heterogeneity of moyamoya disease, see MYMY1 (252350).
Cortical dysplasia, complex, with other brain malformations 5
MedGen UID:
816737
Concept ID:
C3810407
Disease or Syndrome
Gangliosidosis GM1 type 3
MedGen UID:
78655
Concept ID:
C0268273
Disease or Syndrome
GM1-gangliosidosis type III is an autosomal recessive lysosomal storage disorder characterized by neurodegeneration and mild skeletal changes. Age at onset ranges from 3 to 30 years. The disorder is less severe than GM1-gangliosidosis types I and II (230600). Type III shows extreme clinical variability, with some patients having only focal neurologic signs, such as dystonia, and others having more severe involvement with extrapyramidal signs and mental retardation. GLB1 enzymatic activity usually ranges from approximately 4 to 10% of control values (Suzuki et al., 2001).
Neurofaciodigitorenal syndrome
MedGen UID:
163212
Concept ID:
C0796088
Disease or Syndrome
A syndrome of multiple craniofacial anomalies (prominent forehead, ear anomalies, vertical groove on the tip of the nose, megalocephaly, and cowlick), possible heart defect, finger and foot abnormalities, abnormal EEG, developmental delay, and kidney agenesis originally reported in one of two brothers..
Hypotonia-cystinuria syndrome
MedGen UID:
341133
Concept ID:
C1848030
Disease or Syndrome