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Seizures

MedGen UID:
20693
Concept ID:
C0036572
Sign or Symptom
Synonyms: Epilepsy; Seizure
SNOMED CT: Seizure (91175000); Fit (91175000); Fit - convulsion (91175000); Convulsion (91175000); Fitting (91175000)
 
HPO: HP:0001250

Term Hierarchy

CClinical test,  RResearch test,  OOMIM,  GGeneReviews,  VClinVar  
  • CROGVSeizures

Conditions with this feature

Fabry disease
MedGen UID:
8083
Concept ID:
C0002986
Disease or Syndrome
Fabry disease results from deficient activity of the enzyme alpha-galactosidase A (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 (acroparesthesia), the appearance of vascular cutaneous lesions (angiokeratomas), sweating abnormalities (anhidrosis, hypohidrosis, 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: (1) a cardiac variant phenotype that usually presents in the sixth to eighth decade with left ventricular hypertrophy, cardiomyopathy and arrhythmia, and proteinuria, but without ESRD; or (2) a renal variant phenotype, associated with ESRD but without the skin lesions or pain; or (3) cerebrovascular disease presenting as stroke or transient ischemic attack.
Ataxia-telangiectasia syndrome
MedGen UID:
439
Concept ID:
C0004135
Disease or Syndrome
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.
Celiac disease
MedGen UID:
3291
Concept ID:
C0007570
Disease or Syndrome
Celiac disease is a systemic autoimmune 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 non-classic 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 pathogenic variant 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.
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.
Facial hemiatrophy
MedGen UID:
8761
Concept ID:
C0015458
Disease or Syndrome
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 variant and is nearly always characterized by moderate intellectual disability in affected males and mild intellectual disability in affected females. Because FMR1 pathogenic variants 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
Following dietary exposure to fructose, sucrose, or sorbitol, untreated hereditary fructose intolerance (HFI) is characterized by metabolic disturbances (hypoglycemia, lactic acidemia, hypophosphatemia, hyperuricemia, hypermagnesemia, hyperalaninemia) and clinical findings (nausea, vomiting, and abdominal distress; chronic growth restriction/failure to thrive). Untreated HFI typically first manifests when fructose- and sucrose-containing foods are introduced in the course of weaning young infants from breast milk. If large quantities of fructose are ingested, the infant may acutely develop lethargy, seizures, and/or progressive coma. Untreated HFI may result in renal and hepatic failure. If identified and treated before permanent organ injury occurs, individuals with HFI can experience a normal quality of life and life expectancy.
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).
Cowden syndrome
MedGen UID:
5420
Concept ID:
C0018553
Neoplastic Process
Cowden syndrome and Bannayan-Ruvalcaba-Riley syndrome (BRRS; 153480) share clinical characteristics such as hamartomatous polyps of the gastrointestinal tract, mucocutaneous lesions, and increased risk of developing neoplasms. Furthermore, both conditions and several other distinctive phenotypes are caused by mutations in the PTEN gene. For this reason Marsh et al. (1999) suggested that the spectrum of disorders be referred to as PTEN hamartoma tumor syndrome (PHTS). Approximately 80% of CS patients have PTEN mutations (Blumenthal and Dennis, 2008). Some patients with Cowden syndrome may have immune system defects resulting in increased susceptibility to infections (summary by Browning et al., 2015). Blumenthal and Dennis (2008) provided a detailed review of PTEN hamartoma tumor syndromes. Genetic Heterogeneity of Cowden Syndrome Also see Cowden syndrome-2 (CWS2; 612359), caused by mutation in the SDHB gene (185470) on chromosome 1p36; CWS3 (615106), caused by mutation in the SDHD gene (602690) on chromosome 11q23; CWS4 (615107), caused by hypermethylation of the promoter of the KLLN gene (612105), which shares the same transcription site as the PTEN gene, on chromosome 10q23; CWS5 (615108), caused by mutation in the PIK3CA gene (171834) on chromosome 3q26; CWS6 (615109), caused by mutation in the AKT1 gene (164730) on chromosome 14q32; and CWS7 (616858), caused by mutation in the SEC23B gene (610512) on chromosome 20p11.
Neutral 1 amino acid transport defect
MedGen UID:
6723
Concept ID:
C0018609
Disease or Syndrome
Hartnup disease is a condition caused by the body's inability to absorb certain protein building blocks (amino acids) from the diet. As a result, affected individuals are not able to use these amino acids to produce other substances, such as vitamins and proteins. Most people with Hartnup disease are able to get the vitamins and other substances they need with a well-balanced diet.People with Hartnup disease have high levels of various amino acids in their urine (aminoaciduria). For most affected individuals, this is the only sign of the condition. However, some people with Hartnup disease have episodes during which they exhibit other signs, which can include skin rashes; difficulty coordinating movements (cerebellar ataxia); and psychiatric symptoms, such as depression or psychosis. These episodes are typically temporary and are often triggered by illness, stress, nutrient-poor diet, or fever. These features tend to go away once the trigger is remedied, although the aminoaciduria remains. In affected individuals, signs and symptoms most commonly occur in childhood.
Huntington chorea
MedGen UID:
5654
Concept ID:
C0020179
Disease or Syndrome
Huntington disease (HD) is a progressive disorder of motor, cognitive, and psychiatric disturbances. The mean age of onset is 35 to 44 years and the median survival time is 15 to 18 years after onset.
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; it occurs primarily in females and on occasion in males. 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 seizures, intellectual disability, and developmental delays are occasionally seen.
Hypomelanosis of Ito
MedGen UID:
5920
Concept ID:
C0022283
Congenital Abnormality
Kearns Sayre syndrome
MedGen UID:
9618
Concept ID:
C0022541
Disease or Syndrome
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). 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 symptoms. 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 is an X-linked recessive disorder characterized by generalized copper deficiency. The clinical features result from the dysfunction of several copper-dependent enzymes. De Bie et al. (2007) provided a detailed review of the molecular pathogenesis of Menkes disease.
Klippel Trenaunay syndrome
MedGen UID:
9646
Concept ID:
C0022739
Disease or Syndrome
Klippel-Trenaunay syndrome is a condition that affects the development of blood vessels, soft tissues (such as skin and muscles), 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 torso. 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 blood 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 blood clot known as a pulmonary embolism (PE).Other 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 loss 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 pathogenic variants 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 syndrome
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, juvenile MLD, and adult MLD. Age of onset within a family is usually similar. The disease course may be from several years in the late-infantile-onset form to decades in the juvenile- and adult-onset forms. Late-infantile MLD. Onset is before age 30 months. Typical presenting findings include weakness, hypotonia, clumsiness, frequent falls, toe walking, and dysarthria. As the disease progresses, language, cognitive, and gross and fine motor skills regress. Later signs include spasticity, pain, seizures, and compromised vision and hearing. In the final stages, children have tonic spasms, decerebrate posturing, and general unawareness of their surroundings. Juvenile MLD. Onset is between age 30 months and 16 years. Initial manifestations include decline in school performance and emergence of behavioral problems, followed by gait disturbances. Progression is similar to but slower than in the late-infantile form. Adult MLD. Onset occurs after age 16 years, sometimes not until the fourth or fifth decade. Initial signs can include problems in school or job performance, personality changes, emotional lability, or psychosis; in others, neurologic symptoms (weakness and loss of coordination progressing to spasticity and incontinence) or seizures initially predominate. 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 earlier-onset forms.
Lipid proteinosis
MedGen UID:
6112
Concept ID:
C0023795
Disease or Syndrome
Lipoid proteinosis (LP) is characterized by deposition of hyaline-like material in various tissues resulting in a hoarse voice from early infancy, vesicles and hemorrhagic crusts in the mouth and on the face and extremities, verrucous and keratotic cutaneous lesions on extensor surfaces (especially the elbows), and moniliform blepharosis (multiple beaded papules along the eyelid margins and inner canthus). Extracutaneous manifestations may include epilepsy, neuropsychiatric disorders, and spontaneous CNS hemorrhage. Males and females are affected equally. Generally, the disease course is chronic and fluctuating. Affected individuals have a normal life span unless they experience laryngeal obstruction.
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.
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.
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.
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. The risk of adverse outcome varies based on the degree of PAH deficiency. Without effective therapy, most individuals with severe PAH deficiency, known as classic PKU, develop profound and irreversible intellectual disability. Affected individuals on an unrestricted diet who have phenylalanine levels above normal but below 1200 µmol/L (20 mg/dL) are at much lower risk for impaired cognitive development in the absence of treatment.
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 platelets (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
Disorders of GNAS inactivation include the phenotypes pseudohypoparathyroidism Ia, Ib, and Ic (PHP-Ia, -Ib, -Ic), pseudopseudohypoparathyroidism (PPHP), progressive osseous heteroplasia (POH), and osteoma cutis (OC). PHP-Ia and PHP-Ic are characterized by: End-organ resistance to endocrine hormones including parathyroid hormone (PTH), thyroid-stimulating hormone (TSH), gonadotropins (LH and FSH), growth hormone-releasing hormone (GHRH), and CNS neurotransmitters (leading to obesity and variable degrees of intellectual disability and developmental delay); and The Albright hereditary osteodystrophy (AHO) phenotype (short stature, round facies, and subcutaneous ossifications) and brachydactyly type E (shortening mainly of the 4th and/or 5th metacarpals and metatarsals and distal phalanx of the thumb). Although PHP-Ib is characterized principally by PTH resistance, some individuals also have partial TSH resistance and mild features of AHO (e.g., brachydactyly). PPHP, a more limited form of PHP-Ia, is characterized by various manifestations of the AHO phenotype without the hormone resistance or obesity. POH and OC are even more restricted variants of PPHP: POH consists of dermal ossification beginning in infancy, followed by increasing and extensive bone formation in deep muscle and fascia. OC consists of extra-skeletal ossification that is limited to the dermis and subcutaneous tissues.
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
Rett syndrome
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.
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).
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. The most common clinical manifestation is spontaneous and recurrent nosebleeds (epistaxis) beginning on average at age 12 years. Telangiectases (small AVMs) are most evident on the lips, tongue, buccal mucosa, face, chest, and fingers. The average age of onset is generally later than epistaxis, but may be during childhood. Large AVMs often cause symptoms when they occur in the lungs, liver, or brain; complications from bleeding or shunting may be sudden and catastrophic. Approximately 25% of individuals with HHT have GI bleeding, which most commonly begins after age 50 years.
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
Disease or Syndrome
Zellweger spectrum disorder (ZSD) is a phenotypic continuum ranging from severe to mild. While individual phenotypes (e.g., Zellweger syndrome [ZS], neonatal adrenoleukodystrophy [NALD], and infantile Refsum disease [IRD]) were described in the past before the biochemical and molecular bases of this spectrum were fully determined, the term ZSD is now used to refer to all individuals with a PEX gene defect regardless of phenotype. Individuals with ZSD usually come to clinical attention in the newborn period or later in childhood. Affected newborns are hypotonic and feed poorly. They have distinctive facies, congenital malformations (neuronal migration defects associated with neonatal-onset seizures, renal cysts, and bony stippling [chondrodysplasia punctata] of the patella[e] and other long bones), and liver disease which can be severe. Infants with severe ZSD are significantly impaired and typically die during the first year of life, usually having made no developmental progress. Individuals with intermediate/milder ZSD do not have congenital malformations, but rather progressive peroxisome dysfunction variably manifest as sensory loss (secondary to retinal dystrophy and sensorineural hearing loss); neurologic involvement (ataxia, polyneuropathy, and leukodystrophy); liver dysfunction; adrenal insufficiency; and renal oxalate stones. While hypotonia and developmental delays are typical, intellect can be normal. Some have osteopenia; almost all have ameleogenesis imperfecta in the secondary teeth.
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.
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
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 (the “non-classic” 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 increased 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.
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 characterized by a distinctive facial appearance (broad and prominent forehead, sparse frontotemporal hair, downslanting palpebral fissures, malar flushing, long and narrow face, long chin); learning disability (early developmental delay, mild to severe intellectual impairment); and overgrowth (height and/or head circumference =2 SD above the mean). These three clinical features are considered the cardinal features of Sotos syndrome. Major features of Sotos syndrome include behavioral problems, advanced bone age, cardiac anomalies, cranial MRI/CT abnormalities, joint hyperlaxity/pes planus, maternal preeclampsia, neonatal jaundice, neonatal hypotonia, renal anomalies, scoliosis, and seizures.
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.
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).
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 (616570), 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. Although the disease spectrum is a continuum, six clinical forms are usually recognized based on age at diagnosis and severity of features: Perinatal (severe) hypophosphatasia characterized by respiratory insufficiency and hypercalcemia. Perinatal (benign) hypophosphatasia with prenatal skeletal manifestations that slowly resolve into one of the milder forms. Infantile hypophosphatasia with onset between birth and age six months of rickets without elevated serum alkaline phosphatase activity. Childhood (juvenile) hypophosphatasia that ranges from low bone mineral density for age with unexplained fractures to rickets, and premature loss of primary teeth with intact roots. Adult hypophosphatasia characterized by stress fractures and pseudofractures of the lower extremities in middle age, sometimes associated with early loss of adult dentition. Odontohypophosphatasia characterized by premature exfoliation of primary teeth and/or severe dental caries without skeletal manifestations.
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), Lujan syndrome (LS), and X-linked Ohdo syndrome. 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, prominent nasal bridge, high narrow palate, and short philtrum. Carrier females in families with FGS1 and LS are typically unaffected. X-linked Ohdo syndrome (referred to as XLOS in this GeneReview) is characterized by intellectual disability, blepharophimosis, and facial coarsening. A number of individuals with nonsyndromic intellectual disability – including some affected females – have been described.
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 cognitive impairment from early infancy, whereas the majority have normal or only slightly impaired 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. The biochemical abnormalities that distinguish CTX from other conditions with xanthomas include high plasma and tissue cholestanol concentration, normal-to-low plasma cholesterol concentration, decreased chenodeoxycholic acid, increased concentration of bile alcohols and their glyconjugates, and increased concentrations of cholestanol and apolipoprotein B in cerebrospinal fluid.
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
Weaver syndrome
MedGen UID:
120511
Concept ID:
C0265210
Disease or Syndrome
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.
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
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 allelic variants occur, are laminin alpha-2 (merosin) deficiency (MDC1A), collagen VI-deficient CMD, the dystroglycanopathies (caused by mutation of POMT1, POMT2, FKTN, FKRP, LARGE1, POMGNT1, and ISPD), SELENON (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
Congenital Abnormality
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
Disease or Syndrome
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).
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. Neuropsychiatric concerns can include behavioral problems, loss of strength, progressive spasticity or paraplegia, sleep apnea, or stroke. 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. Characteristic facial features may be more apparent with age. Upper-extremity differences may be subtle and include short, soft, fleshy hands with tapered fingers as well as fleshy forearms. Progressive kyphoscoliosis is one of the most difficult aspects of long-term care. Affected females tend to have intellectual disability in the mild to moderate range and may also have the typical facial, hand, and skeletal findings noted in males.
Adams-Oliver syndrome
MedGen UID:
78544
Concept ID:
C0265268
Disease or Syndrome
Adams-Oliver syndrome (AOS) is characterized by aplasia cutis congenita (ACC) of the scalp and terminal transverse limb defects (TTLD). ACC lesions usually occur in the midline of the parietal or occipital regions, but can also occur on the abdomen or limbs. At birth, an ACC lesion may already have the appearance of a healed scar. ACC lesions less than 5 cm often involve only the skin and almost always heal over a period of months; larger lesions are more likely to involve the skull and possibly the dura, and are at greater risk for complications, which can include infection, hemorrhage, or thrombosis, and can result in death. The limb defects range from mild (unilateral or bilateral short distal phalanges) to severe (complete absence of all toes or fingers, feet or hands, or more, often resembling an amputation). The lower extremities are almost always more severely affected than the upper extremities. Additional major features frequently include cardiovascular malformations/dysfunction (23%), brain anomalies, and less frequently renal, liver, and eye anomalies.
Kenny-Caffey syndrome
MedGen UID:
75560
Concept ID:
C0265291
Disease or Syndrome
Kenny-Caffey syndrome is characterized by severe proportionate short stature, cortical thickening and medullary stenosis of the tubular bones, delayed closure of the anterior fontanel, eye abnormalities, and transient hypocalcemia. Patients with autosomal dominant KCS type 2 have normal intelligence (Kenny and Linarelli, 1966; Caffey, 1967; summary by Isojima et al., 2014). See KCS1 (244460) for a discussion of an autosomal recessive form of Kenny-Caffey syndrome.
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 pathogenic variants 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.
Bannayan-Riley-Ruvalcaba syndrome
MedGen UID:
78554
Concept ID:
C0265326
Disease or Syndrome
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 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 syndrome
MedGen UID:
120535
Concept ID:
C0265328
Congenital Abnormality
Coffin-Siris syndrome
MedGen UID:
75565
Concept ID:
C0265338
Disease or Syndrome
Coffin-Siris syndrome is a multiple malformation syndrome characterized by mental retardation associated with coarse facial features, hypertrichosis, sparse scalp hair, and hypoplastic or absent fifth fingernails or toenails. Other more variable features may include poor overall growth, craniofacial abnormalities, spinal anomalies, and congenital heart defects (review by Vergano and Deardorff, 2014). Mutations in the ARID1B gene are the most common cause of Coffin-Siris syndrome (Wieczorek et al., 2013). Genetic Heterogeneity of Coffin-Siris Syndrome Forms of Coffin-Siris syndrome have been shown to be caused by mutations in genes encoding subunits of the SWI/SNF complex, also known as the BAF complex, which functions as a chromatin remodeling factor. These include CSS2 (614607), caused by mutation in the ARID1A gene (603024); CSS3 (614608), caused by mutation in the SMARCB1 gene (601607); CSS4 (614609), caused by mutation in the SMARCA4 gene (603254); CSS5 (616938), caused by mutation in the SMARCE1 gene (603111); and CSS6 (617808), caused by mutation in the ARID2 gene (609539). A similar phenotype, Nicolaides-Baraitser syndrome (NCBRS; 601358), is also caused by mutation in a subunit of this complex, i.e., SMARCA2 (600014).
Borjeson-Forssman-Lehmann syndrome
MedGen UID:
78557
Concept ID:
C0265339
Disease or Syndrome
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).
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
Adenylosuccinase deficiency is an autosomal recessive inborn error of metabolism caused by an enzymatic defect in de novo purine synthesis (DNPS) pathway. ADSL deficiency leads to the accumulation of toxic intermediates, including succinyladenosine (S-Ado) and succinylaminoimidazole carboxamide riboside (SAICAr) in body fluids. There are 3 major phenotypic forms of the disorder that correlate with different values of the S-Ado and SAICAr concentration ratios (S-Ado/SAICAr) in the cerebrospinal fluid. These include the most severe fatal neonatal encephalopathy (S-Ado/SAICAr ratio less than 1); childhood form (type I) with severe psychomotor retardation (S-Ado/SAICAr ratio close to 1), and a milder form (type II) with psychomotor retardation or hypotonia (S-Ado/SAICAr ratio greater than 2) (summary by Baresova et al., 2012).
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
Leigh syndrome (or subacute necrotizing encephalomyelopathy) is characterized by decompensation (often with elevated lactate levels in blood and/or CSF) during an intercurrent illness. It is typically associated with psychomotor retardation or regression, often followed by transient or prolonged stabilization or even improvement, but inevitably resulting in eventual progressive neurologic decline, typically occurring in stepwise decrements. Neurologic manifestations include hypotonia, spasticity, movement disorders (including chorea), cerebellar ataxia, and peripheral neuropathy. Extraneurologic manifestations may include hypertrophic cardiomyopathy, hypertrichosis, anemia, renal tubulopathy, liver involvement, ptosis, and muscle weakness. Onset is typically between ages three and 12 months; about 50% of affected individuals die by age three years, most often as a result of respiratory or cardiac failure. Later onset (including in adulthood) and long-term survival may occasionally occur.
Acute neuronopathic Gaucher 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.
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.
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
Disease or Syndrome
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). For a phenotypic description and a discussion of genetic heterogeneity of autosomal recessive cutis laxa, see 219100. Genetic Heterogeneity of de Barsy Syndrome Also see ARCL3B (614438), caused by mutation in the PYCR1 gene (179035) on chromosome 17q25.
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. Although the disease spectrum is a continuum, six clinical forms are usually recognized based on age at diagnosis and severity of features: Perinatal (severe) hypophosphatasia characterized by respiratory insufficiency and hypercalcemia. Perinatal (benign) hypophosphatasia with prenatal skeletal manifestations that slowly resolve into one of the milder forms. Infantile hypophosphatasia with onset between birth and age six months of rickets without elevated serum alkaline phosphatase activity. Childhood (juvenile) hypophosphatasia that ranges from low bone mineral density for age with unexplained fractures to rickets, and premature loss of primary teeth with intact roots. Adult hypophosphatasia characterized by stress fractures and pseudofractures of the lower extremities in middle age, sometimes associated with early loss of adult dentition. Odontohypophosphatasia characterized by premature exfoliation of primary teeth and/or severe dental caries without skeletal manifestations.
Deficiency of glycerol kinase
MedGen UID:
82803
Concept ID:
C0268418
Disease or Syndrome
NR0B1-related adrenal hypoplasia congenita includes both X-linked adrenal hypoplasia congenita (X-linked AHC) and Xp21 deletion (previously called complex glycerol kinase deficiency). X-linked AHC is characterized by primary adrenal insufficiency and/or hypogonadotropic hypogonadism (HH). Adrenal insufficiency is acute infantile onset (average age 3 weeks) in approximately 60% of affected males and childhood onset (ages 1-9 years) in approximately 40%. HH typically manifests in a male with adrenal insufficiency as delayed puberty (i.e., onset age >14 years) and less commonly as arrested puberty at about Tanner Stage 3. Rarely, X-linked AHC manifests initially in early adulthood as delayed-onset adrenal insufficiency, partial HH, and/or infertility. Heterozygous females very occasionally have manifestations of adrenal insufficiency or hypogonadotropic hypogonadism. Xp21 deletion includes deletion of NR0B1 (causing X-linked AHC) and GK (causing glycerol kinase deficiency), and in some cases deletion of DMD (causing Duchenne muscular dystrophy). Developmental delay has been reported in males with Xp21 deletion when the deletion extends proximally to include DMD or when larger deletions extend distally to include IL1RAPL1 and DMD.
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). Gitelman syndrome is sometimes referred to as a mild variant of classic Bartter syndrome (607364). For a discussion of genetic heterogeneity of Bartter syndrome, see 607364.
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
The phenotypic spectrum of sepiapterin reductase deficiency (SRD), which ranges from significant motor and cognitive deficits to only minimal findings, has not been completely elucidated. Clinical features in the majority of affected individuals include motor and speech delay, axial hypotonia, dystonia, weakness, and oculogyric crises; symptoms show diurnal fluctuation and sleep benefit. Other common features include parkinsonian signs (tremor, bradykinesia, masked facies, rigidity), limb hypertonia, hyperreflexia, intellectual disability, psychiatric and/or behavioral abnormalities, autonomic dysfunction, and sleep disturbances (hypersomnolence, difficulty initiating or maintaining sleep, and drowsiness). Most affected individuals have nonspecific features in infancy including developmental delays and axial hypotonia; other features develop over time.
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 post-neonatal-onset (partial deficiency) 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 post-neonatal-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).
Hyperlysinuria with hyperammonemia
MedGen UID:
120650
Concept ID:
C0268555
Disease or Syndrome
Hyperleucine-isoleucinemia
MedGen UID:
82821
Concept ID:
C0268574
Disease or Syndrome
Isovaleryl-CoA dehydrogenase deficiency
MedGen UID:
82822
Concept ID:
C0268575
Disease or Syndrome
Isovaleric acidemia is an inborn error of leucine metabolism caused by a deficiency of isovaleryl-CoA dehydrogenase. It can present with severe neonatal ketoacidosis leading to death, but in milder cases recurrent episodes of ketoacidosis of varying degree occur later in infancy and childhood (summary by Vockley et al., 1991).
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 a healthy newborn with poor feeding and decreased arousal in the first few days of life, followed by progressive encephalopathy of unexplained origin. Without prompt diagnosis and management, this is followed by progressive encephalopathy manifesting as lethargy, seizures, or coma that can result in death. It is frequently accompanied by metabolic acidosis with anion gap, lactic acidosis, ketonuria, hypoglycemia, hyperammonemia, and cytopenias. Individuals with late-onset PA may remain asymptomatic and suffer a metabolic crisis under catabolic stress (e.g., illness, surgery, fasting) or may experience a more insidious onset with the development of multiorgan complications including vomiting, protein intolerance, failure to thrive, hypotonia, developmental delays or regression, movement disorders, or cardiomyopathy. Isolated cardiomyopathy 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, 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).
Methylcrotonyl-CoA carboxylase deficiency
MedGen UID:
78691
Concept ID:
C0268600
Disease or Syndrome
3-methylcrotonyl-CoA carboxylase deficiency (also known as 3-MCC deficiency) is an inherited disorder in which the body is unable to process certain proteins properly. People with this disorder have a shortage of an enzyme that helps break down proteins containing a particular building block (amino acid) called leucine.Infants with 3-MCC deficiency appear normal at birth but usually develop signs and symptoms in infancy or early childhood. The characteristic features of this condition, which can range from mild to life-threatening, include feeding difficulties, recurrent episodes of vomiting and diarrhea, excessive tiredness (lethargy), and weak muscle tone (hypotonia). If untreated, this disorder can lead to delayed development, seizures, and coma. Many of these complications can be prevented with early detection and lifelong management with a low-protein diet and appropriate supplements. Some people with gene mutations that cause 3-MCC deficiency never experience any signs or symptoms of the condition.The characteristic features of 3-MCC deficiency are similar to those of Reye syndrome, a severe disorder that develops in children while they appear to be recovering from viral infections such as chicken pox or flu. Most cases of Reye syndrome are associated with the use of aspirin during these viral infections.
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
The spectrum of isolated sulfite oxidase deficiency ranges from classic early-onset (severe) disease to late-onset (mild) disease. Classic ISOD is characterized in the first few hours to days of life by intractable seizures, feeding difficulties, and rapidly progressive encephalopathy manifest as abnormal tone (especially opisthotonus, spastic quadriplegia, and pyramidal signs) followed by progressive microcephaly and profound intellectual disability. Lens subluxation or dislocation, another characteristic finding, may be evident after the newborn period. Children usually die during the first few months of life. Late-onset ISOD manifests between ages six and 18 months and is characterized by ectopia lentis (variably present), developmental delay/regression, movement disorder characterized by dystonia and choreoathetosis, ataxia, and (rarely) acute hemiplegia due to metabolic stroke. The clinical course may be progressive or episodic. In the episodic form encephalopathy, dystonia, choreoathetosis, and/or ataxia are intermittent.
Hyper-beta-alaninemia
MedGen UID:
75702
Concept ID:
C0268630
Disease or Syndrome
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: Infantile neuroaxonal dystrophy (INAD). Atypical neuroaxonal dystrophy (atypical NAD). PLA2G6-related dystonia-parkinsonism. INAD usually begins between ages six months and three years with psychomotor regression or delay, hypotonia, and progressive spastic tetraparesis. Many affected children never learn to walk or lose the ability shortly after attaining it. Strabismus, nystagmus, and optic atrophy are common. Disease progression is rapid, resulting in severe spasticity, progressive cognitive decline, and visual impairment. Many affected children do not survive beyond their 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, ataxia, or speech delay and autistic features, which are sometimes the only evidence of disease for a year or more. Strabismus, nystagmus, and optic atrophy are common. Neuropsychiatric disturbances including impulsivity, poor attention span, hyperactivity, and emotional lability are also common. 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 has a variable age of onset, but most individuals present in early adulthood with gait disturbance or neuropsychiatric changes. Affected individuals consistently develop dystonia and parkinsonism (which may be accompanied by rapid cognitive decline) in their late teens to early twenties. Dystonia is most common in the hands and feet but may be more generalized. The most common features of parkinsonism in these individuals are bradykinesia, resting tremor, rigidity, and postural instability.
Alexander 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
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, highly arched eyebrows, long eyelashes, short nose with anteverted nares, 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
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.
Reading seizure
MedGen UID:
75817
Concept ID:
C0278193
Disease or Syndrome
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
Zellweger spectrum disorder (ZSD) is a phenotypic continuum ranging from severe to mild. While individual phenotypes (e.g., Zellweger syndrome [ZS], neonatal adrenoleukodystrophy [NALD], and infantile Refsum disease [IRD]) were described in the past before the biochemical and molecular bases of this spectrum were fully determined, the term ZSD is now used to refer to all individuals with a PEX gene defect regardless of phenotype. Individuals with ZSD usually come to clinical attention in the newborn period or later in childhood. Affected newborns are hypotonic and feed poorly. They have distinctive facies, congenital malformations (neuronal migration defects associated with neonatal-onset seizures, renal cysts, and bony stippling [chondrodysplasia punctata] of the patella[e] and other long bones), and liver disease which can be severe. Infants with severe ZSD are significantly impaired and typically die during the first year of life, usually having made no developmental progress. Individuals with intermediate/milder ZSD do not have congenital malformations, but rather progressive peroxisome dysfunction variably manifest as sensory loss (secondary to retinal dystrophy and sensorineural hearing loss); neurologic involvement (ataxia, polyneuropathy, and leukodystrophy); liver dysfunction; adrenal insufficiency; and renal oxalate stones. While hypotonia and developmental delays are typical, intellect can be normal. Some have osteopenia; almost all have ameleogenesis imperfecta in the secondary teeth.
Hennekam lymphangiectasia-lymphedema syndrome
MedGen UID:
137946
Concept ID:
C0340834
Disease or Syndrome
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
Diabetes-deafness syndrome maternally transmitted
MedGen UID:
90979
Concept ID:
C0342289
Disease or Syndrome
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
Disease or Syndrome
Hypocalcemia, autosomal dominant 1
MedGen UID:
87438
Concept ID:
C0342345
Disease or Syndrome
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.
Dopamine beta hydroxylase deficiency
MedGen UID:
90992
Concept ID:
C0342687
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.
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. Findings include poor feeding, failure to thrive, and anemia. There can be leukopenia and thrombocytopenia, diarrhea and/or oral mucositis, hypoimmunoglobulinemia, and other immunologic dysfunction resulting in infections, most often Pneumocystis jerovicii pneumonia. 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
GABA-transaminase deficiency is characterized by neonatal or early infantile-onset encephalopathy, hypotonia, hypersomnolence, epilepsy, choreoathetosis, and accelerated linear growth. Electroencephalograms show burst-suppression, modified hypsarrhythmia, multifocal spikes, and generalized spike-wave. Severity varies, but most patients have profound developmental impairment and some patients die in infancy (summary by Koenig et al., 2017).
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 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 disease characterized by the presence of dihydropyrimidinuria. The clinical phenotype is highly variable, ranging from early infantile onset of severe neurologic involvement, dysmorphic features, and feeding problems to late onset of mild intellectual disability and even asymptomatic individuals. Patients with a complete or partial deficiency have an increased risk of developing severe toxicity after administration of the anticancer drug 5-fluorouracil (5-FU) (summary by Nakajima et al., 2017). See also dihydropyrimidine dehydrogenase deficiency (274270), a similar disorder.
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
Disease or Syndrome
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 types: infantile multisystem, late-infantile and childhood ataxia-intellectual disability, and adult stable disability. The three types 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 sibs. In the infantile multisystem type, infants show axial hypotonia, hyporeflexia, esotropia, and developmental delay. Feeding problems, vomiting, failure to thrive, and impaired growth are frequently seen. 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 type, 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 seizures, stroke-like episodes or transient unilateral loss of function, retinitis pigmentosa, joint contractures, and skeletal deformities. In the adult stable disability type, 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 for deep venous thrombosis is present.
Branchiooculofacial syndrome
MedGen UID:
91261
Concept ID:
C0376524
Disease or Syndrome
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 7th cranial nerve weakness). Malformed and prominent pinnae and hearing loss from inner ear and/or petrous bone anomalies are common. Intellect is usually normal.
Lhermitte-Duclos disease
MedGen UID:
140251
Concept ID:
C0391826
Neoplastic Process
Roberts-SC phocomelia syndrome
MedGen UID:
95931
Concept ID:
C0392475
Disease or Syndrome
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.
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).
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 (CNS) anomalies (Moog et al., 2007). The malformations in ECCL are patchy and asymmetric. The most characteristic skin anomaly is nevus psiloliparus, a well-demarcated, alopecic fatty tissue nevus on the scalp, seen in 80% of affected individuals. Other dermatologic features include frontotemporal or zygomatic subcutaneous fatty lipomas, non-scarring alopecia, focal dermal hypoplasia or aplasia of the scalp, periocular skin tags, and pigmentary abnormalities following the lines of Blaschko. Choristomas of the eye (epibulbar dermoids or lipodermoids) are also present in 80% of patients, and can be unilateral or bilateral. Characteristic CNS features in ECCL include intracranial and intraspinal lipomas, seen in 61% of patients, and less often cerebral asymmetry, arachnoid cysts, enlarged ventricles, and leptomeningeal angiomatosis. A predisposition to low-grade gliomas has also been observed. Seizures and intellectual disability are common, but one-third of affected individuals have normal intellect. Skeletal manifestations include bone cysts and jaw tumors, such as odontomas, osteomas, and ossifying fibromas (summary by Bennett et al., 2016).
Kohlschutter syndrome
MedGen UID:
98036
Concept ID:
C0406740
Disease or Syndrome
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.
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
Muscle eye brain disease
MedGen UID:
105341
Concept ID:
C0457133
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 allelic variants occur, are laminin alpha-2 (merosin) deficiency (MDC1A), collagen VI-deficient CMD, the dystroglycanopathies (caused by mutation of POMT1, POMT2, FKTN, FKRP, LARGE1, POMGNT1, and ISPD), SELENON (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).
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) deficiency, and the creatine transporter (CRTR) 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; about 40% have movement disorder. Onset is between ages three months and three years. Only 14 individuals with AGAT deficiency have been reported. The phenotype of CRTR deficiency in affected males ranges from mild intellectual disability and speech delay to severe intellectual disability, seizures, movement disorder and behavior disorder; age at diagnosis ranges from two to 66 years. Clinical phenotype of females heterozygous for CRTR deficiency ranges from asymptomatic to severe phenotype resembling male phenotype.
Cockayne syndrome 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 loss 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 pathogenic variants 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.
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).
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.
Crome syndrome
MedGen UID:
167082
Concept ID:
C0795914
Disease or Syndrome
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
Fountain syndrome
MedGen UID:
208650
Concept ID:
C0795944
Disease or Syndrome
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
Gomez-Lopez-Hernandez syndrome, also known as cerebellotrigeminal dermal dysplasia, 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
Kabuki syndrome
MedGen UID:
162897
Concept ID:
C0796004
Congenital Abnormality
Kabuki syndrome is a disorder that affects many parts of the body. It is characterized by distinctive facial features including arched eyebrows; long eyelashes; long openings of the eyelids (long palpebral fissures) with the lower lids turned out (everted) at the outside edges; a flat, broadened tip of the nose; and large protruding earlobes. The name of this disorder comes from the resemblance of its characteristic facial appearance to stage makeup used in traditional Japanese Kabuki theater.People with Kabuki syndrome have mild to severe developmental delay and intellectual disability. Affected individuals may also have seizures, an unusually small head size (microcephaly), or weak muscle tone (hypotonia). Some have eye problems such as rapid, involuntary eye movements (nystagmus) or eyes that do not look in the same direction (strabismus).Other characteristic features of Kabuki syndrome include short stature and skeletal abnormalities such as abnormal side-to-side curvature of the spine (scoliosis), short fifth (pinky) fingers, or problems with the hip and knee joints. The roof of the mouth may have an abnormal opening (cleft palate) or be high and arched, and dental problems are common in affected individuals. People with Kabuki syndrome may also have fingerprints with unusual features and fleshy pads at the tips of the fingers. These prominent finger pads are called fetal finger pads because they normally occur in human fetuses; in most people they disappear before birth.A wide variety of other health problems occur in some people with Kabuki syndrome. Among the most commonly reported are heart abnormalities, frequent ear infections (otitis media), hearing loss, and early puberty.
Kapur Toriello syndrome
MedGen UID:
208654
Concept ID:
C0796005
Disease or Syndrome
Kifafa seizure disorder
MedGen UID:
208655
Concept ID:
C0796010
Disease or Syndrome
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, characteristic facial features, cleft lip/palate, and variable developmental delay/intellectual disability. 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; intellectual disability can range from mild to severe.
Zimmermann-Laband syndrome
MedGen UID:
208656
Concept ID:
C0796013
Disease or Syndrome
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.
X-linked mental retardation with marfanoid habitus syndrome
MedGen UID:
167096
Concept ID:
C0796022
Congenital Abnormality
The phenotypic spectrum of MED12-related disorders, which is still being defined, includes at a minimum the phenotypes of FG syndrome type 1 (FGS1), Lujan syndrome (LS), and X-linked Ohdo syndrome. 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, prominent nasal bridge, high narrow palate, and short philtrum. Carrier females in families with FGS1 and LS are typically unaffected. X-linked Ohdo syndrome (referred to as XLOS in this GeneReview) is characterized by intellectual disability, blepharophimosis, and facial coarsening. A number of individuals with nonsyndromic intellectual disability – including some affected females – have been described.
Mac Dermot Winter syndrome
MedGen UID:
162900
Concept ID:
C0796024
Disease or Syndrome
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
Gurrieri syndrome
MedGen UID:
208660
Concept ID:
C0796046
Disease or Syndrome
Linear skin defects with multiple congenital anomalies 1
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 connective tissue disorder with multisystem involvement, progressive and proliferative fibrosis that may occur spontaneously or following trauma or surgery, mild-to-moderate intellectual disability, and in some instances, autistic-like behaviors. Organ systems primarily involved include: cardiovascular (congenital heart defects, long- and short-segment stenosis of the aorta and peripheral arteries, pericardial effusion, constrictive pericarditis, restrictive cardiomyopathy, and hypertension); respiratory (choanal stenosis, laryngotracheal narrowing, obstructive airway disease, or restrictive pulmonary disease), gastrointestinal (pyloric stenosis, duodenal strictures, severe constipation); and skin (thickened particularly on the hands and extensor surfaces). Additional findings include distinctive craniofacial features and skeletal involvement (intrauterine growth restriction, short stature, limited joint range of motion). To date, 55 individuals with molecularly confirmed Myhre syndrome have been reported.
Megalocornea mental retardation syndrome
MedGen UID:
162904
Concept ID:
C0796086
Disease or Syndrome
Oculocerebrocutaneous syndrome
MedGen UID:
163214
Concept ID:
C0796092
Disease or Syndrome
Mental retardation, congenital heart disease, blepharophimosis, blepharoptosis and hypoplastic teeth
MedGen UID:
162905
Concept ID:
C0796094
Disease or Syndrome
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
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).
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 disability. 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 pathogenic variants in the AGS-related genes is not yet known.
Ramon Syndrome
MedGen UID:
208669
Concept ID:
C0796133
Disease or Syndrome
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.
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.
Parkinsonism, early onset with mental retardation
MedGen UID:
208674
Concept ID:
C0796195
Disease or Syndrome
Waisman syndrome is an X-linked 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).
Worster Drought syndrome
MedGen UID:
163228
Concept ID:
C0796204
Disease or Syndrome
Atkin syndrome
MedGen UID:
163230
Concept ID:
C0796206
Disease or Syndrome
Mental retardation, X-linked 14
MedGen UID:
163231
Concept ID:
C0796220
Disease or Syndrome
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
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).
Pettigrew syndrome
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
Oculodentodigital dysplasia
MedGen UID:
167236
Concept ID:
C0812437
Congenital Abnormality
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 allelic variants occur, are laminin alpha-2 (merosin) deficiency (MDC1A), collagen VI-deficient CMD, the dystroglycanopathies (caused by mutation of POMT1, POMT2, FKTN, FKRP, LARGE1, POMGNT1, and ISPD), SELENON (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.
Cardio-facio-cutaneous syndrome
MedGen UID:
266149
Concept ID:
C1275081
Congenital Abnormality
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.
Deficiency of glycerate kinase
MedGen UID:
226941
Concept ID:
C1291386
Disease or Syndrome
D-glyceric aciduria is a 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, whereas 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 sparse scalp hair, prominence of the inter-phalangeal joints and distal phalanges due to decreased subcutaneous fat, characteristic coarse facial features, microcephaly, seizures, and developmental delay / intellectual disability. Seizures are of various types and can be difficult to manage. Developmental delay / intellectual disability (ID) is severe in nearly a half, moderate in a third, and mild in the remainder. Nearly a third never develop speech or language skills.
Oral-facial-digital syndrome
MedGen UID:
307142
Concept ID:
C1510460
Disease or Syndrome
Oral-facial-digital syndrome type I (OFD1) is usually male lethal during gestation and predominantly affects females. OFD1 is characterized by the following features: Oral (lobulated tongue, tongue nodules, 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, clinodactyly of the fifth finger; duplicated hallux [great toe]). Kidney (polycystic kidney disease). Brain (e.g., intracerebral cysts, agenesis of the corpus callosum, cerebellar agenesis with or without Dandy-Walker malformation). Intellectual disability (in ~50% of individuals).
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.
Peroxisome biogenesis disorders, Zellweger syndrome spectrum
MedGen UID:
330407
Concept ID:
C1832200
Disease or Syndrome
Zellweger spectrum disorder (ZSD) is a phenotypic continuum ranging from severe to mild. While individual phenotypes (e.g., Zellweger syndrome [ZS], neonatal adrenoleukodystrophy [NALD], and infantile Refsum disease [IRD]) were described in the past before the biochemical and molecular bases of this spectrum were fully determined, the term ZSD is now used to refer to all individuals with a PEX gene defect regardless of phenotype. Individuals with ZSD usually come to clinical attention in the newborn period or later in childhood. Affected newborns are hypotonic and feed poorly. They have distinctive facies, congenital malformations (neuronal migration defects associated with neonatal-onset seizures, renal cysts, and bony stippling [chondrodysplasia punctata] of the patella[e] and other long bones), and liver disease which can be severe. Infants with severe ZSD are significantly impaired and typically die during the first year of life, usually having made no developmental progress. Individuals with intermediate/milder ZSD do not have congenital malformations, but rather progressive peroxisome dysfunction variably manifest as sensory loss (secondary to retinal dystrophy and sensorineural hearing loss); neurologic involvement (ataxia, polyneuropathy, and leukodystrophy); liver dysfunction; adrenal insufficiency; and renal oxalate stones. While hypotonia and developmental delays are typical, intellect can be normal. Some have osteopenia; almost all have ameleogenesis imperfecta in the secondary teeth.
Microcephaly, corpus callosum dysgenesis and cleft lip-palate
MedGen UID:
330448
Concept ID:
C1832369
Disease or Syndrome
Mental retardation, microcephaly, epilepsy, and coarse face
MedGen UID:
330468
Concept ID:
C1832437
Disease or Syndrome
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 glycosylation (CDGs) are a genetically heterogeneous group of autosomal recessive disorders caused by enzymatic defects in the synthesis and processing of asparagine (N)-linked glycans or oligosaccharides on glycoproteins. Type I CDGs comprise defects in the assembly of the dolichol lipid-linked oligosaccharide (LLO) chain and its transfer to the nascent protein. These disorders can be identified by a characteristic abnormal isoelectric focusing profile of plasma transferrin (Leroy, 2006). CDG1D is a type I CDG that generally presents with severe neurologic involvement associated with dysmorphism and visual impairment. Liver involvement is sometimes present (summary by Marques-da-Silva et al., 2017). For a discussion of the classification of CDGs, see CDG1A (212065).
Ayme-gripp syndrome
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).
Epilepsy, focal, with speech disorder and with or without mental retardation
MedGen UID:
322043
Concept ID:
C1832814
Disease or Syndrome
GRIN2A-related speech disorders and epilepsy are characterized by speech disorders in all affected individuals and a range of epilepsy syndromes present in about 90%. Severe speech disorders observed can include dysarthria and speech dyspraxia, and both receptive and expressive language delay/regression; more mildly affected individuals may display subtly impaired intelligibility of conversational speech. Epilepsy features include seizure onset usually between ages three and six years, focal epilepsy with language and/or global developmental regression, and electroencephalogram (EEG) showing continuous spike-and-wave discharges in sleep or very active centrotemporal discharges. Seizure types include seizures associated with aura of perioral paresthesia, focal or focal motor seizures (often evolving to generalized tonic-clonic), and atypical absence seizures. Epilepsy syndromes can include: Landau-Kleffner syndrome (LKS), epileptic encephalopathy with continuous spike-and-wave during sleep (ECSWS), childhood epilepsy with centrotemporal spikes (CECTS), atypical childhood epilepsy with centrotemporal spikes (ACECTS), autosomal dominant rolandic epilepsy with speech dyspraxia (ADRESD), and infantile-onset epileptic encephalopathy.
Permanent neonatal diabetes mellitus
MedGen UID:
371484
Concept ID:
C1833104
Disease or Syndrome
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). The diabetes mellitus is associated with partial or complete insulin deficiency. Clinical manifestations at the time of diagnosis include intrauterine growth retardation, hyperglycemia, glycosuria, osmotic polyuria, severe dehydration, and failure to thrive. Therapy with insulin corrects the hyperglycemia and results in dramatic catch-up growth. The course of PNDM varies by genotype.
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 the most frequent cause of hereditary myoglobinuria. Males are more likely to be affected than females.
Carnitine palmitoyl transferase II deficiency, neonatal form
MedGen UID:
318896
Concept ID:
C1833518
Disease or Syndrome
The neonatal form of carnitine palmitoyltransferase II (CPT II) deficiency (see this term), an inherited disorder that affects mitochondrial oxidation of long chain fatty acids (LCFA), is the lethal form of the disease which presents with multisystem failure.
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 loss 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 pathogenic variants 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.
Cerebelloparenchymal Disorder VI
MedGen UID:
331813
Concept ID:
C1834711
Disease or Syndrome
Cerebellar Granule Cell Hypertrophy and Megalencephaly
MedGen UID:
371886
Concept ID:
C1834712
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
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.
Holoprosencephaly 7
MedGen UID:
372134
Concept ID:
C1835820
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
DOLK-congenital disorder of glycosylation (DOLK-CDG, formerly known as congenital disorder of glycosylation type Im) is an inherited condition that often affects the heart but can also involve other body systems. The pattern and severity of this disorder's signs and symptoms vary among affected individuals.Individuals with DOLK-CDG typically develop signs and symptoms of the condition during infancy or early childhood. Nearly all individuals with DOLK-CDG develop a weakened and enlarged heart (dilated cardiomyopathy). Other frequent signs and symptoms include recurrent seizures; developmental delay; poor muscle tone (hypotonia); and dry, scaly skin (ichthyosis). Less commonly, affected individuals can have distinctive facial features, kidney disease, hormonal abnormalities, or eye problems.Individuals with DOLK-CDG typically do not survive into adulthood, often because of complications related to dilated cardiomyopathy, and some do not survive past infancy.
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).
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).
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 loss 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 pathogenic variants 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 pre- and postnatal growth deficiency, microcephaly, hypotonia, severe global developmental delays, ear anomalies, preauricular tags or pits, cleft or high-arched palate, congenital heart defects, kidney abnormalities, and genital abnormalities in males.
Stomatin-deficient cryohydrocytosis with neurologic defects
MedGen UID:
332390
Concept ID:
C1837206
Disease or Syndrome
Stomatin-deficient cryohydrocytosis with neurologic defects is an autosomal dominant disorder characterized by delayed psychomotor development, seizures, cataracts, and pseudohyperkalemia resulting from defects in the red blood cell membrane. The disorder combines the neurologic features of Glut1 deficiency syndrome-1 (GLUT1DS1; 606777), resulting from impaired glucose transport at the blood-brain barrier, and hemolytic anemia/pseudohyperkalemia with stomatocytosis, resulting from a cation leak in erythrocytes (summary by Bawazir et al., 2012). For a discussion of clinical and genetic heterogeneity of red cell stomatocyte disorders, see 194380.
Cleft palate, isolated
MedGen UID:
332392
Concept ID:
C1837218
Congenital Abnormality
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
Pelizaeus-Merzbacher-like disease 1 (PMLD1) is a slowly progressive leukodystrophy that typically presents during the neonatal or early-infantile period with nystagmus, commonly associated with hypotonia, delayed acquisition of motor milestones, speech delay, and dysarthria. Over time the hypotonia typically evolves into spasticity that affects the ability to walk and communicate. Cerebellar signs (gait ataxia, dysmetria, intention tremor, head titubation, and dysdiadochokinesia) frequently manifest during childhood. Some individuals develop extrapyramidal movement abnormalities (choreoathetosis and dystonia). Hearing loss and optic atrophy are observed in rare cases. Motor impairments can lead to swallowing difficulty and orthopedic complications, including hip dislocation and scoliosis. Most individuals have normal cognitive skills or mild intellectual disability – which, however, can be difficult to evaluate in the context of profound motor impairment.
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.
Epilepsy, idiopathic generalized 3
MedGen UID:
373335
Concept ID:
C1837468
Finding
AICAR transformylase/IMP cyclohydrolase deficiency
MedGen UID:
332474
Concept ID:
C1837530
Disease or Syndrome
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. The most common clinical manifestation is spontaneous and recurrent nosebleeds (epistaxis) beginning on average at age 12 years. Telangiectases (small AVMs) are most evident on the lips, tongue, buccal mucosa, face, chest, and fingers. The average age of onset is generally later than epistaxis, but may be during childhood. Large AVMs often cause symptoms when they occur in the lungs, liver, or brain; complications from bleeding or shunting may be sudden and catastrophic. Approximately 25% of individuals with HHT have GI bleeding, which most commonly begins after age 50 years.
Spastic paraplegia 6
MedGen UID:
324965
Concept ID:
C1838192
Disease or Syndrome
Band heterotopia
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
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 loss 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 pathogenic variants 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.
Wolfram syndrome, mitochondrial form
MedGen UID:
325511
Concept ID:
C1838782
Disease or Syndrome
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), NDUFAF1 (606934), TMEM126B (615533), TIMMDC1 (615534), and NDUFA13 (609435). 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 (300078) and NDUFB11 (300403) genes. 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
Disease or Syndrome
Pyruvate dehydrogenase E1-alpha deficiency
MedGen UID:
326486
Concept ID:
C1839413
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 11p13; a form (PDHBD; 614111) caused by mutation in the PDHB gene (179060) on chromosome 3p14; a form (PDHDD; 245348) caused by mutation in the DLAT gene (608770) on chromosome 11q23; 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.
Mental retardation, X-linked, syndromic 12
MedGen UID:
333405
Concept ID:
C1839792
Disease or Syndrome
Corpus callosum, partial agenesis of, X-linked
MedGen UID:
374339
Concept ID:
C1839909
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).
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
Lipodystrophy, generalized, with mental retardation, deafness, short stature, and slender bones
MedGen UID:
334166
Concept ID:
C1842465
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.
Pontocerebellar hypoplasia type 3
MedGen UID:
334225
Concept ID:
C1842687
Congenital Abnormality
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
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.
Basal ganglia disease, biotin-responsive
MedGen UID:
375289
Concept ID:
C1843807
Disease or Syndrome
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+”).
Coenzyme Q10 deficiency, primary 1
MedGen UID:
334528
Concept ID:
C1843920
Disease or Syndrome
Primary coenzyme Q10 (CoQ10) deficiency is usually associated with multisystem involvement, including neurologic manifestations such as fatal neonatal encephalopathy with hypotonia; a late-onset slowly progressive multiple-system atrophy-like phenotype (neurodegeneration with autonomic failure and various combinations of parkinsonism and cerebellar ataxia, and pyramidal dysfunction); and dystonia, spasticity, seizures, and intellectual disability. Steroid-resistant nephrotic syndrome (SRNS), the hallmark renal manifestation, is often the initial manifestation either as isolated renal involvement that progresses to end-stage renal disease (ESRD), or associated with encephalopathy (seizures, stroke-like episodes, severe neurologic impairment) resulting in early death. Hypertrophic cardiomyopathy (HCM), retinopathy or optic atrophy, and sensorineural hearing loss can also be seen.
Hhhh 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).
Spinocerebellar ataxia X-linked type 3
MedGen UID:
337124
Concept ID:
C1844936
Disease or Syndrome
Pigmentary disorder, reticulate, with systemic manifestations, X-linked
MedGen UID:
336844
Concept ID:
C1845050
Disease or Syndrome
X-linked reticulate pigmentary disorder shows more severe manifestations in hemizygous males compared to heterozygous females. Affected males have early onset of recurrent respiratory infections and failure to thrive resulting from inflammatory gastroenteritis or colitis. Patients also show reticular pigmentation abnormalities of the skin and may develop corneal scarring. Carrier females may be unaffected or have only pigmentary abnormalities along the lines of Blaschko (summary by Starokadomskyy et al., 2016).
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).
Bone mineral density quantitative trait locus 4
MedGen UID:
337191
Concept ID:
C1845236
Finding
Mental retardation, X-linked 82
MedGen UID:
337201
Concept ID:
C1845286
Disease or Syndrome
Mental retardation, X-linked 52
MedGen UID:
375624
Concept ID:
C1845298
Disease or Syndrome
Mental retardation X-linked with cerebellar hypoplasia and distinctive facial appearance
MedGen UID:
336920
Concept ID:
C1845366
Disease or Syndrome
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 mitochondrial disease most commonly presents as an X-linked neurodegenerative disorder with highly variable severity and age at onset ranging from the neonatal period to early childhood. The features are usually multisystemic, consistent with mitochondrial dysfunction. Some affected males have a severe infantile form associated with cardiomyopathy that may result in death in early childhood, whereas other rare patients may have juvenile onset or even atypical presentations with normal neurologic development. More severely affected males show developmental regression in infancy or early childhood, often associated with early-onset intractable seizures, progressive choreoathetosis and spastic tetraplegia, optic atrophy or retinal degeneration resulting in visual loss, and mental retardation. Heterozygous females may show non-progressive developmental delay and intellectual disability, but may also be clinically normal. Although the diagnosis can be aided by the observation of increased urinary levels of metabolites of isoleucine breakdown (2-methyl-3 hydroxybutyrate and tiglylglycine), there is not a correlation between these laboratory features and the phenotype. In addition, patients do not develop severe metabolic crises in the neonatal period as observed in other organic acidurias, but may show persistent lactic acidosis, most likely reflecting mitochondrial dysfunction (summary by Rauschenberger et al., 2010; review by Zschocke, 2012). In a review of the disorder, Zschocke (2012) noted that although this disorder was originally thought to be an inborn error of branched-chain fatty acid and isoleucine metabolism resulting from decreased HSD17B10 dehydrogenase activity (HSD17B10 'deficiency'), subsequent studies have shown that the HSD17B10 gene product has additional functions and also acts as a component of the mitochondrial RNase P holoenzyme, which is involved in mitochondrial tRNA processing and maturation and ultimately mitochondrial protein synthesis. The multisystemic features of HSD10MD most likely result from the adverse effect of HSD17B10 mutations on mitochondrial function, rather than from the effects on the dehydrogenase activity (see PATHOGENESIS below).
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) deficiency, and the creatine transporter (CRTR) 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; about 40% have movement disorder. Onset is between ages three months and three years. Only 14 individuals with AGAT deficiency have been reported. The phenotype of CRTR deficiency in affected males ranges from mild intellectual disability and speech delay to severe intellectual disability, seizures, movement disorder and behavior disorder; age at diagnosis ranges from two to 66 years. Clinical phenotype of females heterozygous for CRTR deficiency ranges from asymptomatic to severe phenotype resembling male phenotype.
Mental retardation, X-linked 72
MedGen UID:
375793
Concept ID:
C1846038
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.
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).
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
GLUT1 deficiency syndrome is a disorder affecting the nervous system that can have a variety of neurological signs and symptoms. Approximately 90 percent of affected individuals have a form of the disorder often referred to as common GLUT1 deficiency syndrome. These individuals generally have frequent seizures (epilepsy) beginning in the first months of life. In newborns, the first sign of the disorder may be involuntary eye movements that are rapid and irregular. Babies with common GLUT1 deficiency syndrome have a normal head size at birth, but growth of the brain and skull is often slow, which can result in an abnormally small head size (microcephaly). People with this form of GLUT1 deficiency syndrome may have developmental delay or intellectual disability. Most affected individuals also have other neurological problems, such as stiffness caused by abnormal tensing of the muscles (spasticity), difficulty in coordinating movements (ataxia), and speech difficulties (dysarthria). Some experience episodes of confusion, lack of energy (lethargy), headaches, or muscle twitches (myoclonus), particularly during periods without food (fasting).About 10 percent of individuals with GLUT1 deficiency syndrome have a form of the disorder often known as non-epileptic GLUT1 deficiency syndrome, which is usually less severe than the common form. People with the non-epileptic form do not have seizures, but they may still have developmental delay and intellectual disability. Most have movement problems such as ataxia or involuntary tensing of various muscles (dystonia); the movement problems may be more pronounced than in the common form.Several conditions that were originally given other names have since been recognized to be variants of GLUT1 deficiency syndrome. These include paroxysmal choreoathetosis with spasticity (dystonia 9); paroxysmal exercise-induced dyskinesia and epilepsy (dystonia 18); and certain types of epilepsy. In rare cases, people with variants of GLUT1 deficiency syndrome produce abnormal red blood cells and have uncommon forms of a blood condition known as anemia, which is characterized by a shortage of red blood cells.
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.
Periventricular nodular heterotopia 1
MedGen UID:
376309
Concept ID:
C1848213
Congenital Abnormality
FLNA-related periventricular nodular heterotopia (PVNH), 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 most often 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 cardiovascular disease, stroke, and other vascular/coagulation problems appears to be increased.
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). The disorder is caused by a defect in glycosylphosphatidylinositol (GPI) biosynthesis. For a discussion of genetic heterogeneity of GPI biosynthesis defects, see GPIBD1 (610293).
Xylosidase deficiency
MedGen UID:
336338
Concept ID:
C1848407
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 rhabdomyolysis complicating severe infections. 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.
Thyrocerebral-retinal syndrome
MedGen UID:
341311
Concept ID:
C1848813
Disease or Syndrome
Threoninemia
MedGen UID:
336439
Concept ID:
C1848861
Finding
Knobloch syndrome 1
MedGen UID:
336594
Concept ID:
C1849409
Disease or Syndrome
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
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).
PEHO syndrome
MedGen UID:
342404
Concept ID:
C1850055
Disease or Syndrome
PEHO is a severe autosomal recessive neurodevelopmental disorder characterized by extreme cerebellar atrophy due to almost total loss of granule neurons. Affected individuals present in early infancy with hypotonia, profoundly delayed psychomotor development, optic atrophy, progressive atrophy of the cerebellum and brainstem, and dysmyelination. Most patients also develop infantile seizures that are often associated with hypsarrhythmia on EEG, and many have peripheral edema (summary by Anttonen et al., 2017).
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).
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 loss 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 pathogenic variants 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 loss 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 pathogenic variants 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.
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
PAX2-related disorder is an autosomal dominant disorder associated with renal and eye abnormalities. The disorder was originally referred to as renal coloboma syndrome and characterized by renal hypodysplasia and abnormalities of the optic nerve; with improved access to molecular testing, a wider range of phenotypes has been recognized in association with pathogenic variants in PAX2. Abnormal renal structure or function is noted in 92% of affected individuals and ophthalmologic abnormalities in 77% of affected individuals. 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. Uric acid nephrolithiasis has been reported. Ophthalmologic abnormalities are typically described as optic nerve coloboma or dysplasia. Iris colobomas have not been reported in any individual with PAX2–related disorder. Ophthalmologic abnormalities may significantly impair vision in some individuals, while others have subtle changes only noted after detailed ophthalmologic examination. Additional clinical findings include high-frequency sensorineural hearing loss, soft skin, and ligamentous laxity. PAX2 pathogenic variants have been identified in multiple sporadic and familial cases of nonsyndromic renal disease including renal hypodysplasia and focal segmental glomerulosclerosis.
Glycosylphosphatidylinositol deficiency
MedGen UID:
342819
Concept ID:
C1853205
Disease or Syndrome
Glycophosphatidylinositol is a glycolipid that anchors more than 150 proteins to the cell surface, and these proteins, termed GPI-anchored proteins (GPI-APs), have various important roles. Reduced surface levels of GPI-APs or abnormal GPI-AP structure can cause various symptoms, mainly including intellectual disability, and sometimes other congenital malformations, seizures, or dysmorphic facial features (summary by Makrythanasis et al., 2016). Genetic Heterogeneity of Glycosylphosphatidylinositol Biosynthesis Defects Also see GPIBD2 (239300), caused by mutation in the PIGV gene (610274); GPIBD3 (614080), caused by mutation in the PIGN gene (606097); GPIBD4 (300868), caused by mutation in the PIGA gene (311770); GPIBD5 (280000), caused by mutation in the PIGL gene (605947); GPIBD6 (614749), caused by mutation in the PIGO gene (614730); GPIBD7 (615398), caused by mutation in the PIGT gene (610272); GPIBD8 (614207), caused by mutation in the PGAP2 gene (615187); GPIBD9 (615802), caused by mutation in the PGAP1 gene (611655); GPIBD10 (615716), caused by mutation in the PGAP3 gene (611801); GPIBD11 (616025), caused by mutation in the PIGW gene (610275); GPIBD12 (616809), caused by mutation in the PIGY gene (610662); GPIBD13 (616917), caused by mutation in the PIGG gene (616918); GPIBD14 (617599), caused by mutation in the PIGP gene (605938); GPIBD15 (617810), caused by mutation in the GPAA1 gene (603048); and GPIBD16 (617816), caused by mutation in the PIGC gene (601730).
Pachygyria, frontotemporal
MedGen UID:
343995
Concept ID:
C1853215
Disease or Syndrome
Congenital disorder of glycosylation type 2B
MedGen UID:
342954
Concept ID:
C1853736
Disease or Syndrome
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.
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
Mitochondrial complex II deficiency is an autosomal recessive disorder with a highly variable phenotype. Some patients have multisystem involvement of the brain, heart, muscle, liver, and kidneys resulting in death in infancy, whereas others have only isolated cardiac or muscle involvement with onset in adulthood and normal cognition. Measurement of complex II activity in muscle is the most reliable means of diagnosis; however, there is no clear correlation between residual complex II activity and severity or clinical outcome. In some cases, treatment with riboflavin may have clinical benefit (summary by Jain-Ghai et al., 2013).
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, the topic of this GeneReview, is caused by complete or partial deficiency of the enzyme methylmalonyl-CoA mutase (mut0 enzymatic subtype or mut– enzymatic subtype, respectively), a defect in the transport or synthesis of its cofactor, adenosyl-cobalamin (cblA, cblB, or cblD-MMA), 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 are characterized by 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 within the first four weeks of life. In the infantile/non-B12-responsive phenotype, infants are normal at birth, but develop lethargy, vomiting, dehydration, failure to thrive, hepatomegaly, hypotonia, and encephalopathy within a few weeks to months of age. An intermediate B12-responsive phenotype can occasionally be observed in neonates, but is usually observed 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 phenotypes are associated with increased, albeit mild, urinary excretion of methylmalonate. Major secondary complications of methylmalonic acidemia include: intellectual impairment (variable); tubulointerstitial nephritis with progressive renal failure; “metabolic stroke” (acute and chronic basal ganglia injury) causing a disabling movement disorder with choreoathetosis, dystonia, and para/quadriparesis; pancreatitis; growth failure; functional immune impairment; and optic nerve atrophy.
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
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
Keutel 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
Baraitser-Winter cerebrofrontofacial (BWCFF) syndrome is a multiple congenital anomaly syndrome characterized by typical craniofacial features and intellectual disability (ID) that ranges from mild (usually in those with normal brain structure) to profound (typically in those with a neuronal migration defect). Many (but not all) affected individuals have iris or retinal coloboma, sensorineural deafness, and muscle wasting resulting in a peculiar stance with kyphosis, anteverted shoulders, and slightly flexed elbows and knees. Seizures, congenital heart defects, and renal malformations also are common.
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 (ACC), 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).
Bartter syndrome, type 2, antenatal
MedGen UID:
343428
Concept ID:
C1855849
Disease or Syndrome
Bartter syndrome refers to a group of disorders that are unified by autosomal recessive transmission of impaired salt reabsorption in the thick ascending loop of Henle with pronounced salt wasting, hypokalemic metabolic alkalosis, and hypercalciuria. Clinical disease results from defective renal reabsorption of sodium chloride in the thick ascending limb (TAL) of the Henle loop, where 30% of filtered salt is normally reabsorbed (Simon et al., 1997). Patients with antenatal forms of Bartter syndrome typically present with premature birth associated with polyhydramnios and low birth weight and may develop life-threatening dehydration in the neonatal period. Patients with classic Bartter syndrome (see BARTS3, 607364) present later in life and may be sporadically asymptomatic or mildly symptomatic (summary by Simon et al., 1996 and Fremont and Chan, 2012). For a discussion of genetic heterogeneity of Bartter syndrome, see 607364.
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
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).
Hall Riggs mental retardation syndrome
MedGen UID:
341089
Concept ID:
C1856198
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
Pontocerebellar hypoplasia type 4
MedGen UID:
384027
Concept ID:
C1856974
Congenital Abnormality
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 rhabdomyolysis complicating severe infections. 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
2,4-Dienoyl-CoA reductase deficiency
MedGen UID:
346552
Concept ID:
C1857252
Disease or Syndrome
DECR deficiency is a rare autosomal recessive inborn error of metabolism resulting in mitochondrial dysfunction. Affected individuals have a severe encephalopathy with neurologic and metabolic dysfunction beginning in early infancy. Laboratory studies show decreased activity of the mitochondrial NADP(H)-dependent enzymes DECR1 (222745) and AASS (605113), resulting in increased C10:2-carnitine levels and hyperlysinemia (summary by Houten et al., 2014).
Diaminopentanuria
MedGen UID:
347412
Concept ID:
C1857285
Disease or Syndrome
Polycystic lipomembranous osteodysplasia with sclerosing leukoencephalopathy
MedGen UID:
387795
Concept ID:
C1857316
Disease or Syndrome
Polycystic lipomembranous osteodysplasia with sclerosing leukoencephalopathy (PLOSL) is characterized by fractures (resulting from radiologically demonstrable polycystic osseous lesions), frontal lobe syndrome, and progressive presenile dementia beginning in the fourth decade. The clinical course of PLOSL can be divided into four stages: (1) The latent stage is characterized by normal early development. (2) The osseous stage (3rd decade of life) is characterized by pain and tenderness, mostly in ankles and feet, usually following strain or injury. Fractures are typically diagnosed several years later, most commonly in the bones of the extremities. (3) In the early neurologic stage (4th decade of life), a change of personality begins to develop insidiously. Affected individuals show a frontal lobe syndrome (loss of judgment, euphoria, loss of social inhibitions, disturbance of concentration, and lack of insight, libido, and motor persistence) leading to serious social problems. (4) The late neurologic stage is characterized by progressive dementia and loss of mobility. Death usually occurs before age 50 years.
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
Craniofacial dyssynostosis
MedGen UID:
347473
Concept ID:
C1857511
Disease or Syndrome
Convulsive disorder, familial, with prenatal or early onset
MedGen UID:
387859
Concept ID:
C1857575
Disease or Syndrome
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: Infantile neuroaxonal dystrophy (INAD). Atypical neuroaxonal dystrophy (atypical NAD). PLA2G6-related dystonia-parkinsonism. INAD usually begins between ages six months and three years with psychomotor regression or delay, hypotonia, and progressive spastic tetraparesis. Many affected children never learn to walk or lose the ability shortly after attaining it. Strabismus, nystagmus, and optic atrophy are common. Disease progression is rapid, resulting in severe spasticity, progressive cognitive decline, and visual impairment. Many affected children do not survive beyond their 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, ataxia, or speech delay and autistic features, which are sometimes the only evidence of disease for a year or more. Strabismus, nystagmus, and optic atrophy are common. Neuropsychiatric disturbances including impulsivity, poor attention span, hyperactivity, and emotional lability are also common. 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 has a variable age of onset, but most individuals present in early adulthood with gait disturbance or neuropsychiatric changes. Affected individuals consistently develop dystonia and parkinsonism (which may be accompanied by rapid cognitive decline) in their late teens to early twenties. Dystonia is most common in the hands and feet but may be more generalized. The most common features of parkinsonism in these individuals are bradykinesia, resting tremor, rigidity, and postural instability.
Pontocerebellar hypoplasia type 5
MedGen UID:
341845
Concept ID:
C1857762
Congenital Abnormality
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 rhabdomyolysis complicating severe infections. 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.
Williams-Beuren region duplication syndrome
MedGen UID:
347562
Concept ID:
C1857844
Disease or Syndrome
7q11.23 duplication syndrome is characterized by distinctive facial features; cardiovascular disease (dilation of the ascending aorta in 46%); neurologic abnormalities (hypotonia, adventitious movements, and abnormal gait and station); speech sound disorders including motor speech disorders (childhood apraxia of speech and/or dysarthria) and phonologic disorders; behavior problems including anxiety disorders (especially social anxiety disorder [social phobia]), selective mutism, attention deficit hyperactivity disorder (ADHD), oppositional disorders, physical aggression, and autism spectrum disorders (ASD); delayed motor, speech, and social skills in early childhood; and intellectual ability ranging from intellectual disability (~18%) to borderline intellectual ability (~20%) to low average to high average (the remainder). Approximately 30% of individuals with the 7q11.23 duplication have one or more congenital anomalies.
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.
Epilepsy, familial focal, with variable foci 1
MedGen UID:
348951
Concept ID:
C1858477
Disease or Syndrome
DEPDC5-related epilepsy encompasses a range of epilepsy syndromes, almost all of which are characterized by focal seizures, with seizure onset in a discrete area of the brain. While most individuals with DEPDC5-related epilepsy have a normal brain MRI, some have epilepsy associated with a cortical malformation, usually focal cortical dysplasia. Seizure syndromes include familial focal epilepsy with variable foci (FFEVF), autosomal dominant nocturnal frontal lobe epilepsy (ADNFLE), familial mesial temporal lobe epilepsies (FMTLE), autosomal dominant epilepsy with auditory features (ADEAF), and infantile spasms. Although psychomotor development is usually normal, intellectual disability or autism spectrum disorder has been reported in some individuals.
Encephalopathy, familial, 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.
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.
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 (zellweger)
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.
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
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 2 deficiency
MedGen UID:
347898
Concept ID:
C1859499
Disease or Syndrome
3-methylcrotonyl-CoA carboxylase deficiency (also known as 3-MCC deficiency) is an inherited disorder in which the body is unable to process certain proteins properly. People with this disorder have a shortage of an enzyme that helps break down proteins containing a particular building block (amino acid) called leucine.Infants with 3-MCC deficiency appear normal at birth but usually develop signs and symptoms in infancy or early childhood. The characteristic features of this condition, which can range from mild to life-threatening, include feeding difficulties, recurrent episodes of vomiting and diarrhea, excessive tiredness (lethargy), and weak muscle tone (hypotonia). If untreated, this disorder can lead to delayed development, seizures, and coma. Many of these complications can be prevented with early detection and lifelong management with a low-protein diet and appropriate supplements. Some people with gene mutations that cause 3-MCC deficiency never experience any signs or symptoms of the condition.The characteristic features of 3-MCC deficiency are similar to those of Reye syndrome, a severe disorder that develops in children while they appear to be recovering from viral infections such as chicken pox or flu. Most cases of Reye syndrome are associated with the use of aspirin during these viral infections.
Berry aneurysm, cirrhosis, pulmonary emphysema, and cerebral calcification
MedGen UID:
347170
Concept ID:
C1859519
Disease or Syndrome
Ataxia with myoclonic epilepsy and presenile dementia
MedGen UID:
347924
Concept ID:
C1859646
Disease or Syndrome
Angiomatosis, diffuse corticomeningeal, of Divry and Van Bogaert
MedGen UID:
347234
Concept ID:
C1859783
Disease or Syndrome
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).
Choreoathetosis, familial inverted
MedGen UID:
348393
Concept ID:
C1861569
Disease or Syndrome
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.'
Arteritis, familial granulomatous, with juvenile polyarthritis
MedGen UID:
349529
Concept ID:
C1862510
Disease or Syndrome
Alopecia, epilepsy, pyorrhea, mental subnormality
MedGen UID:
350833
Concept ID:
C1863090
Disease or Syndrome
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.
Megalencephaly-polymicrogyria-polydactyly-hydrocephalus syndrome 1
MedGen UID:
355095
Concept ID:
C1863924
Disease or Syndrome
The MPPH syndrome is a developmental brain disorder characterized by megalencephaly (brain overgrowth) with the cortical malformation bilateral perisylvian polymicrogyria (BPP). At birth the occipital frontal circumference (OFC) ranges from normal to 6 standard deviations (SD) above the mean for age, sex, and gestational age; in older individuals the range is from 3 to 10 SD above the mean. A variable degree of ventriculomegaly is seen in almost all children with MPPH syndrome; nearly 50% of those have frank hydrocephalus. Neurologic problems associated with BPP include oromotor dysfunction (100%), epilepsy (50%), and mild to severe intellectual disability (100%). Postaxial hexadactyly occurs in 50% of individuals with MPPH syndrome.
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 FCCM remain symptom free throughout their lives. Cutaneous vascular lesions are found in 9% of those with familial cerebral cavernous malformations (FCCM; see Diagnosis/testing) and retinal vascular lesions in almost 5%.
Chromosome 16p13.3 deletion syndrome, proximal
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
Hypomyelination and Congenital Cataract
MedGen UID:
501134
Concept ID:
C1864663
Congenital Abnormality
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.
Microphthalmia syndromic 5
MedGen UID:
350491
Concept ID:
C1864690
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.
Pyridoxal 5'-phosphate-dependent epilepsy
MedGen UID:
350498
Concept ID:
C1864723
Disease or Syndrome
PNPOD is an autosomal recessive inborn error of metabolism resulting in vitamin B6 deficiency that manifests as neonatal-onset severe seizures and subsequent encephalopathy. Patients with PNPO mutations tend to respond better to treatment with pyridoxal 5-prime phosphate (PLP) than with pyridoxine (summary by Plecko et al., 2014).
Combined oxidative phosphorylation deficiency 3
MedGen UID:
355842
Concept ID:
C1864840
Disease or Syndrome
Cortical dysplasia-focal epilepsy syndrome
MedGen UID:
355859
Concept ID:
C1864887
Disease or Syndrome
PTHSL1 is an autosomal recessive neurodevelopmental disorder characterized by delayed psychomotor development, intellectual disability, severe speech impairment or regression, and behavioral abnormalities. Most patients have onset of seizures within the first years of life. Some patients may have cortical dysplasia on brain imaging (summary by Smogavec et al., 2016).
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 (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).
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 allelic variants occur, are laminin alpha-2 (merosin) deficiency (MDC1A), collagen VI-deficient CMD, the dystroglycanopathies (caused by mutation of POMT1, POMT2, FKTN, FKRP, LARGE1, POMGNT1, and ISPD), SELENON (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
Disease or Syndrome
PIK3CA-associated segmental overgrowth includes disorders of brain (e.g., MCAP [megalencephaly-capillary malformation] syndrome, hemimegalencephaly); and segmental body overgrowth (e.g., CLOVES [congenital lipomatous asymmetric overgrowth of the trunk, lymphatic, capillary, venous, and combined-type vascular malformations, epidermal nevi, skeletal and spinal anomalies] syndrome, fibroadipose hyperplasia [FH]). Heterozygous (usually somatic mosaic) pathogenic variants of PIK3CA are causative. MCAP syndrome is characterized by the major findings of (1) megalencephaly (MEG) or hemimegalencephaly (HMEG) associated with neurologic findings of hypotonia, seizures, and mild to severe intellectual disability; and (2) cutaneous capillary malformations with focal or generalized somatic overgrowth. Additional findings can include digital anomalies (syndactyly, polydactyly), cortical malformations – most distinctively polymicrogyria (PMG); and variable connective tissue dysplasia. CLOVES (or CLOVE) syndrome and fibroadipose hyperplasia (FH) may be associated with (1) MEG or HMEG; and (2) patchy segmental overgrowth associated with skeletal anomalies, lipomatosis, vascular malformations, and epidermal nevi.
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 (EE) is a severe, early-onset, progressive disorder characterized by developmental delay / mild-to-severe intellectual disability; generalized infantile hypotonia that evolves into hypertonia, spasticity, and (in some instances) dystonia; generalized tonic-clonic seizures; and generalized microvascular damage (diffuse and spontaneous relapsing petechial purpura, hemorrhagic suffusions of mucosal surfaces, and chronic hemorrhagic diarrhea). Infants sometimes have frequent vomiting and loss of social interaction. Speech is delayed and in some instances absent. Swallowing difficulties and failure to thrive are common. Children may be unable to walk without support and may be wheelchair bound. Neurologic deterioration accelerates following intercurrent infectious illness, and the majority of children die in the first decade.
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).
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 (review 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 loss 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 pathogenic variants 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.
Proteus-like syndrome
MedGen UID:
356222
Concept ID:
C1866398
Disease or Syndrome
Bartter syndrome, type 1, antenatal
MedGen UID:
355727
Concept ID:
C1866495
Disease or Syndrome
Bartter syndrome refers to a group of disorders that are unified by autosomal recessive transmission of impaired salt reabsorption in the thick ascending loop of Henle with pronounced salt wasting, hypokalemic metabolic alkalosis, and hypercalciuria. Clinical disease results from defective renal reabsorption of sodium chloride in the thick ascending limb (TAL) of the Henle loop, where 30% of filtered salt is normally reabsorbed (Simon et al., 1997). Patients with antenatal forms of Bartter syndrome typically present with premature birth associated with polyhydramnios and low birth weight and may develop life-threatening dehydration in the neonatal period. Patients with classic Bartter syndrome (see BARTS3, 607364) present later in life and may be sporadically asymptomatic or mildly symptomatic (summary by Simon et al., 1996 and Fremont and Chan, 2012). For a discussion of genetic heterogeneity of Bartter syndrome, see 607364.
Spastic paraplegia epilepsy mental retardation
MedGen UID:
356631
Concept ID:
C1866854
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
Disease or Syndrome
Familial porencephaly is part of a group of conditions called the COL4A1-related disorders. The conditions in this group have a range of signs and symptoms that involve fragile blood vessels. In familial porencephaly, fluid-filled cysts develop in the brain (porencephaly) during fetal development or soon after birth. These cysts typically occur in only one side of the brain and vary in size. The cysts are thought to be the result of bleeding within the brain (hemorrhagic stroke). People with this condition also have leukoencephalopathy, which is a change in a type of brain tissue called white matter that can be seen with magnetic resonance imaging (MRI).During infancy, people with familial porencephaly typically have paralysis affecting one side of the body (infantile hemiplegia). Affected individuals may also have recurrent seizures (epilepsy), migraine headaches, speech problems, intellectual disability, and uncontrolled muscle tensing (dystonia). Some people are severely affected, and others may have no symptoms related to the brain cysts.
Patterson pseudoleprechaunism syndrome
MedGen UID:
358350
Concept ID:
C1868546
Disease or Syndrome
Parietal foramina 1
MedGen UID:
401480
Concept ID:
C1868599
Congenital Abnormality
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.
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.
Addison 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 can 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 loss 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 pathogenic variants 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.
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).
Severe neonatal-onset encephalopathy with microcephaly
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
The tubulinopathies are a wide and overlapping range of brain malformations caused by mutation of one of seven genes encoding different isotypes of tubulin. Brain malformations include: A range of lissencephalies (classic lissencephaly, lissencephaly with cerebellar hypoplasia, lissencephaly with agenesis of the corpus callosum, and centrally predominant pachygyria), Polymicrogyria-like cortical dysplasia, Simplified gyral pattern, and Microlissencephaly often in combination with dysplastic basal ganglia, corpus callosum abnormalities, and hypoplasia or dysplasia of the brain stem and cerebellum. Clinical features include motor and intellectual disabilities, epilepsy, and ocular findings of varying severity.
Pontocerebellar hypoplasia type 6
MedGen UID:
370596
Concept ID:
C1969084
Congenital Abnormality
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).
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 episodes 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 are brought on by alcohol, caffeine, stress, fatigue, menses, or excitement or develop without a known cause. 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 dyskinesia 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). The dyskinesia also affects muscles in the torso and face. The type of abnormal movement varies among affected individuals, even among affected members of the same family. Individuals with familial paroxysmal nonkinesigenic dyskinesia do not lose consciousness during an episode. Most people do not experience any 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 to 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.
Phosphoserine aminotransferase deficiency
MedGen UID:
410026
Concept ID:
C1970253
Disease or Syndrome
Deficiency of phosphoserine aminotransferase (PSAT) 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.
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 oxidative phosphorylation deficiency 5
MedGen UID:
435972
Concept ID:
C2673642
Disease or Syndrome
Severe achondroplasia with developmental delay and acanthosis nigricans
MedGen UID:
393098
Concept ID:
C2674173
Congenital Abnormality
SADDAN (severe achondroplasia with developmental delay and acanthosis nigricans) is a rare disorder of bone growth characterized by skeletal, brain, and skin abnormalities.All people with this condition have extremely short stature with particularly short arms and legs. Other features include unusual bowing of the leg bones; a small chest with short ribs and curved collar bones; short, broad fingers; and folds of extra skin on the arms and legs. Structural abnormalities of the brain cause seizures, profound developmental delay, and intellectual disability. Several affected individuals also have had episodes in which their breathing slows or stops for short periods (apnea). Acanthosis nigricans, a progressive skin disorder characterized by thick, dark, velvety skin, is another characteristic feature of SADDAN that develops in infancy or early childhood.
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 chromosome locus) in which pathogenic variants occur.
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 herpes virus 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
Chromosome 1q41-q42 deletion syndrome
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 central front tooth instead of two (a single maxillary central incisor), 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.
Leukodystrophy, hypomyelinating, 6
MedGen UID:
436642
Concept ID:
C2676244
Disease or Syndrome
TUBB4A-related leukodystrophy comprises a phenotypic spectrum in which the MRI findings range from hypomyelination with atrophy of the basal ganglia and cerebellum (H-ABC) at the severe end to isolated hypomyelination at the mild end. Progressive neurologic findings reflect involvement of the pyramidal tracts (spasticity, brisk deep tendon reflexes, and Babinski sign), extrapyramidal system (rigidity, dystonia, choreoathetosis, oculogyric crisis, and perioral dyskinesia), cerebellum (ataxia, intention tremor, dysmetria), and bulbar function (dysarthria, dysphonia, and swallowing). Cognition is variably affected, usually less severely than motor function. Typically, those with H-ABC present in early childhood (ages one to three years) and those with isolated hypomyelination in later childhood or adulthood. The rate of progression varies with disease severity.
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 rhabdomyolysis complicating severe infections. 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.
Mental retardation, autosomal dominant 22
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). Patients with autosomal dominant mental retardation-22 have a phenotype similar to that in patients with chromosome 1q43-q44 deletion syndrome (de Munnik et al., 2014).
Chromosome 2q32-q33 deletion syndrome
MedGen UID:
436765
Concept ID:
C2676739
Disease or Syndrome
SATB2-associated syndrome (SAS) is a multisystem disorder characterized by significant neurodevelopmental compromise with limited to absent speech, behavioral issues, and craniofacial anomalies. All individuals described to date have manifest developmental delay / intellectual disability, with severe speech delay. Affected individuals often have hypotonia and feeding difficulties in infancy. Behavioral issues may include autistic features, hyperactivity, and aggressiveness. Craniofacial anomalies may include palatal abnormalities (cleft palate, high-arched palate, and bifid uvula), micrognathia, and abnormal shape or size of the upper central incisors. Less common features include skeletal anomalies (osteopenia, pectus deformities, kyphosis/lordosis, and scoliosis), growth restriction, strabismus/refractive errors, congenital heart defects, genitourinary anomalies, and epilepsy. While dysmorphic features have been described in individuals with this condition, these features are not typically distinctive enough to allow for a clinical diagnosis of SAS.
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).
Leukodystrophy, hypomyelinating, 4
MedGen UID:
383026
Concept ID:
C2677109
Disease or Syndrome
Cerebroretinal microangiopathy with calcifications and cysts 1
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. Genetic Heterogeneity of Cerebroretinal Microangiopathy With Calcifications And Cysts See also CRMCC2 (617341), caused by mutation in the STN1 gene (613128) on chromosome 10q24.
Congenital disorder of glycosylation type 1N
MedGen UID:
383145
Concept ID:
C2677590
Disease or Syndrome
Congenital disorders of glycosylation (CDGs) are a genetically heterogeneous group of autosomal recessive disorders caused by enzymatic defects in the synthesis and processing of asparagine (N)-linked glycans or oligosaccharides on glycoproteins. Type I CDGs comprise defects in the assembly of the dolichol lipid-linked oligosaccharide (LLO) chain and its transfer to the nascent protein. These disorders can be identified by a characteristic abnormal isoelectric focusing profile of plasma transferrin (Leroy, 2006). For a discussion of the classification of CDGs, see CDG1A (212065).
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. The underlying cause of these episodes is the onset of fast ventricular tachycardia (bidirectional or polymorphic). Spontaneous recovery may occur 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) 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.
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).
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
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. The onset of atypical HUS (aHUS) ranges from the neonatal period to adulthood. Genetic aHUS accounts for an estimated 60% of all aHUS. Individuals with genetic aHUS frequently experience relapse even after complete recovery following the presenting episode; 60% 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
RRM2B-related mitochondrial disease can be grouped by disease pathogenesis, phenotype, and mode of inheritance into two major types: mitochondrial DNA (mtDNA) depletion and multiple mtDNA deletions. Mitochondrial DNA depletion usually manifests as severe multisystem disease (encephalomyopathy with proximal renal tubulopathy) and is often fatal in early life. Inheritance is autosomal recessive. Multiple mtDNA deletions cause tissue-specific cytochrome c oxidase (COX) deficiency. Inheritance can be either autosomal recessive (with progressive external ophthalmoplegia [PEO] and multisystem involvement manifesting during early childhood/adulthood) or autosomal dominant (with less severe, often tissue-specific manifestations [e.g., chronic PEO] developing in later adulthood). Other rarer phenotypes are Kearns-Sayre syndrome (KSS) and mitochondrial neurogastrointestinal encephalopathy (MNGIE).
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, encephalomyopathic form with methylmalonic aciduria is characterized by onset of the following features in infancy or childhood (median age of onset 2 months; range of onset birth to 6 years): psychomotor retardation, hypotonia, dystonia, muscular atrophy, sensorineural hearing impairment, postnatal growth retardation, and feeding difficulties. Other less frequent features include distinctive facial features, contractures, kyphoscoliosis, gastroesophageal reflux, ptosis, choreoathetosis, ophthalmoplegia, and epilepsy (infantile spasms or generalized convulsions). The median survival is 20 years; approximately 30% of affected individuals succumb during childhood. Affected individuals may have hyperintensities in the basal ganglia, cerebral atrophy, and leukoencephalopathy on head MRI. Elevation of methylmalonic acid (MMA) in the urine and plasma is found in a vast majority of affected individuals, although at levels that are far below those typically seen in individuals with classic methylmalonic aciduria.
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
Congenital fibrosis of the extraocular muscles (CFEOM) refers to at least eight genetically defined strabismus syndromes (CFEOM1A, CFEOM1B, CFEOM2, CFEOM3A, CFEOM3B, CFEOM3C, Tukel syndrome, and CFEOM3 with polymicrogyria) characterized by congenital non-progressive ophthalmoplegia (inability to move the eyes) with or without ptosis (droopy eyelids) affecting part or all of the oculomotor nucleus and nerve (cranial nerve III) and its innervated muscles (superior, medial, and inferior recti, inferior oblique, and levator palpabrae superioris) and/or the trochlear nucleus and nerve (cranial nerve IV) and its innervated muscle (the superior oblique). In general, affected individuals have severe limitation of vertical gaze (usually upgaze) and variable limitation of horizontal gaze. Individuals with CFEOM frequently compensate for the ophthalmoplegia by maintaining abnormal head positions at rest and by moving their heads rather than their eyes to track objects. Individuals with CFEOM3A may also have intellectual disability, social disability, Kallmann syndrome, facial weakness, and vocal cord paralysis; and/or may develop a progressive sensorimotor axonal polyneuropathy. Individuals with Tukel syndrome also have postaxial oligodactyly or oligosyndactyly of the hands. Those with CFEOM3 with polymicrogyria also have microcephaly and intellectual disability.
Polymicrogyria with optic nerve hypoplasia
MedGen UID:
442565
Concept ID:
C2750798
Disease or Syndrome
The tubulinopathies are a wide and overlapping range of brain malformations caused by mutation of one of seven genes encoding different isotypes of tubulin. Brain malformations include: A range of lissencephalies (classic lissencephaly, lissencephaly with cerebellar hypoplasia, lissencephaly with agenesis of the corpus callosum, and centrally predominant pachygyria), Polymicrogyria-like cortical dysplasia, Simplified gyral pattern, and Microlissencephaly often in combination with dysplastic basal ganglia, corpus callosum abnormalities, and hypoplasia or dysplasia of the brain stem and cerebellum. Clinical features include motor and intellectual disabilities, epilepsy, and ocular findings of varying severity.
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.
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).
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, and CPSQ3 (617008), caused by mutation in the ADD3 gene (601568) on 10q24. 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
Congenital Abnormality
Growth retardation, developmental delay, and facial dysmorphism (GDFD) is an autosomal recessive multiple congenital anomaly syndrome characterized by severe psychomotor retardation, poor overall growth, and dysmorphic facial features. Additional features may include cardiac malformations and deafness (summary by Daoud et al., 2016).
Spastic paraplegia 50, autosomal recessive
MedGen UID:
442869
Concept ID:
C2752008
Disease or Syndrome
Spastic paraplegia-50 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 Verkerk et al., 2009).
Congenital disorder of glycosylation type 1C
MedGen UID:
443952
Concept ID:
C2930997
Disease or Syndrome
Congenital disorders of glycosylation, previously called carbohydrate-deficient glycoprotein syndromes (CDGSs), are caused by defects in mannose addition during N-linked oligosaccharide assembly. CDGs can be divided into 2 types, depending on whether they impair lipid-linked oligosaccharide (LLO) assembly and transfer (CDG I), or affect trimming of the protein-bound oligosaccharide or the addition of sugars to it (CDG II) (Orlean, 2000). CDG Ic is characterized by psychomotor retardation with delayed walking and speech, hypotonia, seizures, and sometimes protein-losing enteropathy. It is the second largest subtype of CDG (summary by Sun et al., 2005). For a discussion of the classification of CDGs, see CDG1A (212065). Freeze and Aebi (1999) reviewed CDG Ib (602579) and CDG Ic.
Congenital disorder of glycosylation type 1J
MedGen UID:
419694
Concept ID:
C2931004
Disease or Syndrome
Like all CDGs, which are caused by a shortage of precursor monosaccharide phosphate or deficiencies in the glycosyltransferases required for lipid-linked oligosaccharide precursor (LLO) synthesis, CDG Ij is caused by a defect in the formation of DPAGT1, the first dolichyl-linked intermediate of the protein N-glycosylation pathway. For a general discussion of CDGs, see CDG1A (212065).
Congenital disorder of glycosylation type 1K
MedGen UID:
419308
Concept ID:
C2931005
Disease or Syndrome
Congenital disorders of glycosylation (CDGs) comprise a group of multisystem diseases with mostly severe psychomotor and mental retardation. Type I CDG comprises those disorders in which there are defects that affect biosynthesis of dolichol-linked oligosaccharides in the cytosol or the endoplasmic reticulum (ER), as well as defects involving the transfer of oligosaccharides onto nascent glycoproteins. Type II CDG comprises all defects of further trimming and elongation of N-linked oligosaccharides in the ER and Golgi (Schwarz et al., 2004). CDG1K is a type I CDG characterized by predominant neurologic involvement. Survival ranges from the second day of life to adulthood. The liver is affected in a minority of patients and shows hepatomegaly, edema, ascites, cholestatic jaundice, portal hypertension, and Budd-Chiari syndrome (summary by Marques-da-Silva et al., 2017). For a general discussion of CDGs, see CDG1A (212065).
ALG9 congenital disorder of glycosylation
MedGen UID:
443955
Concept ID:
C2931006
Disease or Syndrome
Congenital disorders of glycosylation (CDGs) that represent defects of dolichol-linked oligosaccharide assembly are classified as CDG type I. For a general description and a discussion of the classification of CDGs, see CDG1A (212065).
Clark-Baraitser syndrome
MedGen UID:
443983
Concept ID:
C2931130
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.
GLUT1 deficiency syndrome 1, autosomal recessive
MedGen UID:
460468
Concept ID:
C3149117
Disease or Syndrome
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.
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 involvement of the eye (ectopia lentis and/or severe myopia), skeletal system (excessive height, long limbs, scolioisis, and pectus excavatum), vascular system (thromboembolism), and CNS (developmental delay/intellectual disability). All four ? or only one ? of the systems can be involved; expressivity is variable for all of the clinical signs. It is not unusual for a previously asymptomatic individual to present in adult years with only a thromboembolic event that is often cerebrovascular. Two phenotypic variants are recognized, B6-responsive homocystinuria and B6-non-responsive homocystinuria. B6-responsive homocystinuria is usually milder than the non-responsive variant. 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 of the skin and hair, 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 allelic variants occur, are laminin alpha-2 (merosin) deficiency (MDC1A), collagen VI-deficient CMD, the dystroglycanopathies (caused by mutation of POMT1, POMT2, FKTN, FKRP, LARGE1, POMGNT1, and ISPD), SELENON (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.
Early infantile epileptic encephalopathy 10
MedGen UID:
462017
Concept ID:
C3150667
Disease or Syndrome
Microcephaly, seizures, and developmental delay is an autosomal recessive neurodevelopmental disorder with onset in infancy. There is a range of phenotypic severity: some patients have a disease course consistent with early infantile epileptic encephalopathy (EIEE), whereas others have more well-controlled seizures and a protracted course associated with cerebellar atrophy and peripheral neuropathy (Shen et al., 2010 and Poulton et al., 2013). For a general phenotypic description and a discussion of genetic heterogeneity of EIEE, see EIEE1 (308350).
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
Chromosome 19p13.13 deletion syndrome
MedGen UID:
462244
Concept ID:
C3150894
Disease or Syndrome
19p13.13 deletion syndrome is a condition that results from a chromosomal change in which a small piece of chromosome 19 is deleted in each cell. The deletion occurs on the short (p) arm of the chromosome at a position designated p13.13.Features commonly associated with this chromosomal change include an unusually large head size (macrocephaly), tall stature, and intellectual disability that is usually moderate in severity. Many affected individuals have significantly delayed development, including speech, and children may speak few or no words. Weak muscle tone (hypotonia) and problems with coordinating muscle movement (ataxia) contribute to delays in gross motor skills (such as sitting and walking) and fine motor skills (such as holding a pencil).Other signs and symptoms that can occur with 19p13.13 deletion syndrome include seizures, abnormalities of brain structure, and mild differences in facial features (such as a prominent forehead). Many affected individuals have problems with feeding and digestion, including constipation, diarrhea, vomiting, and abdominal pain. Eye problems that can impair vision are also common. These include eyes that do not point in the same direction (strabismus) and underdevelopment of the optic nerves, which carry visual information from the eyes to the brain.The signs and symptoms of 19p13.13 deletion syndrome vary among affected individuals. In part, this variation occurs because the size of the deletion, and the number of genes it affects, varies from person to person.
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
Microcephaly, postnatal progressive, with seizures and brain atrophy
MedGen UID:
462271
Concept ID:
C3150921
Disease or Syndrome
LEOPARD syndrome 3
MedGen UID:
462321
Concept ID:
C3150971
Disease or Syndrome
Noonan syndrome with multiple lentigines (NSML) is a condition in which the cardinal features consist of lentigines, hypertrophic cardiomyopathy, short stature, pectus deformity, and dysmorphic facial features, including widely spaced eyes and ptosis. Multiple lentigines present as dispersed flat, black-brown macules, mostly on the face, neck and upper part of the trunk with sparing of the mucosa. In general, lentigines do not appear until age four to five years but then increase to the thousands by puberty. Some individuals with NSML do not exhibit lentigines. Approximately 85% of affected individuals have heart defects, including hypertrophic cardiomyopathy (HCM) (typically appearing during infancy and sometimes progressive) and pulmonary valve stenosis. Postnatal growth retardation resulting in short stature occurs in fewer than 50% of affected persons, although most affected individuals have a height that is less than the 25th percentile for age. Sensorineural hearing deficits, present in approximately 20%, are poorly characterized. Intellectual disability, typically mild, is observed in approximately 30% of persons with NSML.
Early infantile epileptic encephalopathy 7
MedGen UID:
462336
Concept ID:
C3150986
Disease or Syndrome
KCNQ2-related disorders represent a continuum of overlapping neonatal epileptic phenotypes caused by a heterozygous pathogenic variant in KCNQ2. The clinical features of KCNQ2-related disorders range from KCNQ2-related benign familial neonatal epilepsy (KCNQ2-BFNE) at the mild end to KCNQ2-related neonatal epileptic encephalopathy (KCNQ2-NEE) at the severe end. KCNQ2-BFNE is characterized by a wide spectrum of seizure types (tonic or apneic episodes, focal clonic activity, or autonomic changes) that start in otherwise healthy infants between the second and eighth day of life and spontaneously disappear between the first and the sixth to twelfth month of life. Motor activity may be confined to one body part, migrate to other body regions, or generalize. Seizures are generally brief, lasting one to two minutes. Rarely, KCNQ2-BFNE may evolve into status epilepticus. About 10%-15% of individuals with BFNE develop epileptic seizures later in life. KCNQ2-NEE is characterized by multiple daily seizures beginning in the first week of life that are mostly tonic, with associated focal motor and autonomic features. Seizures generally cease between ages nine months and four years. At onset, EEG shows a burst-suppression pattern or multifocal epileptiform activity; early brain MRI can show basal ganglia and thalamic hyperintensities that later resolve. Moderate to severe developmental impairment is present.
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).
Brain malformations and urinary tract defects
MedGen UID:
462386
Concept ID:
C3151036
Disease or Syndrome
Spastic paraplegia 51, autosomal recessive
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.
Mitochondrial DNA depletion syndrome 9 (encephalomyopathic with methylmalonic aciduria)
MedGen UID:
462826
Concept ID:
C3151476
Disease or Syndrome
SUCLG1-related mitochondrial DNA (mtDNA) depletion syndrome, encephalomyopathic form with methylmalonic aciduria is characterized in the majority of affected newborns by hypotonia, muscle atrophy, feeding difficulties, and lactic acidosis. Affected infants commonly manifest developmental delay / cognitive impairment, growth retardation / failure to thrive, hepatopathy, sensorineural hearing impairment, dystonia, and hypertonia. Notable findings in some affected individuals include hypertrophic cardiomyopathy, epilepsy, myoclonus, microcephaly, sleep disturbance, rhabdomyolysis, contractures, hypothermia, and/or hypoglycemia. Life span is shortened, with median survival of 20 months.
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 neonatal multisystem disorder and an isolated hepatic disorder that presents later in infancy or childhood. The majority of affected individuals have the multisystem illness with hepatic disease (jaundice, cholestasis, hepatomegaly, and elevated transaminases) and neurologic manifestations (hypotonia, nystagmus, and psychomotor retardation) evident within weeks of birth. 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
The NSDHL-related disorders include: CHILD (congenital hemidysplasia with ichthyosiform nevus and limb defects) syndrome, an X-linked dominant condition that is usually male lethal during gestation and thus predominantly affects females; and CK syndrome, an X-linked recessive disorder that affects males. CHILD syndrome is characterized by unilateral distribution of ichthyosiform (yellow scaly) skin lesions and ipsilateral limb defects that range from shortening of the metacarpals and phalanges to absence of the entire limb. Intellect is usually normal. The ichthyosiform skin lesions are usually present at birth or in the first weeks of life; new lesions can develop in later life. Nail changes are also common. The heart, lung, and kidneys can also be involved. CK syndrome (named for the initials of the original proband) is characterized by mild to severe cognitive impairment and behavior problems (aggression, attention deficit hyperactivity disorder, and irritability). All affected males reported have developed seizures in infancy and have cerebral cortical malformations and microcephaly. All have distinctive facial features, a thin habitus, and relatively long, thin fingers and toes. Some have scoliosis and kyphosis.
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.
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 (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.
Geleophysic dysplasia 1
MedGen UID:
479777
Concept ID:
C3278147
Disease or Syndrome
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.
N-acetylaspartate deficiency
MedGen UID:
481346
Concept ID:
C3279716
Disease or Syndrome
Spastic paraplegia 47, autosomal recessive
MedGen UID:
481368
Concept ID:
C3279738
Disease or Syndrome
Spastic paraplegia-47 is an autosomal recessive neurodegenerative disorder characterized by neonatal hypotonia that progresses to hypertonia and spasticity and severe mental retardation with poor or absent speech development (summary by Abou Jamra et al., 2011).
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). The disorder is caused by a defect in glycosylphosphatidylinositol biosynthesis; see GPIBD1 (610293). 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
Mental retardation, autosomal recessive 16
MedGen UID:
481784
Concept ID:
C3280154
Disease or Syndrome
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 (AOS) is characterized by aplasia cutis congenita (ACC) of the scalp and terminal transverse limb defects (TTLD). ACC lesions usually occur in the midline of the parietal or occipital regions, but can also occur on the abdomen or limbs. At birth, an ACC lesion may already have the appearance of a healed scar. ACC lesions less than 5 cm often involve only the skin and almost always heal over a period of months; larger lesions are more likely to involve the skull and possibly the dura, and are at greater risk for complications, which can include infection, hemorrhage, or thrombosis, and can result in death. The limb defects range from mild (unilateral or bilateral short distal phalanges) to severe (complete absence of all toes or fingers, feet or hands, or more, often resembling an amputation). The lower extremities are almost always more severely affected than the upper extremities. Additional major features frequently include cardiovascular malformations/dysfunction (23%), brain anomalies, and less frequently renal, liver, and eye anomalies.
Warburg micro syndrome 3
MedGen UID:
481833
Concept ID:
C3280203
Disease or Syndrome
RAB18 deficiency is the molecular deficit underlying both Warburg micro syndrome (characterized by eye, nervous system, and endocrine abnormalities) and Martsolf syndrome (characterized by similar – but milder – findings). To date Warburg micro syndrome comprises >96% of reported individuals with genetically defined RAB18 deficiency. The hallmark ophthalmologic findings are bilateral congenital cataracts, usually accompanied by microphthalmia, microcornea (diameter <10), and small atonic pupils. Poor vision despite early cataract surgery likely results from progressive optic atrophy and cortical visual impairment. Individuals with Warburg micro syndrome have severe to profound intellectual disability (ID); those with Martsolf syndrome have mild to moderate ID. Some individuals with RAB18 deficiency also have epilepsy. In Warburg micro syndrome, a progressive ascending spastic paraplegia typically begins with spastic diplegia and contractures during the first year, followed by upper limb involvement leading to spastic quadriplegia after about age five years, often eventually causing breathing difficulties. In Martsolf syndrome infantile hypotonia is followed primarily by slowly progressive lower limb spasticity. Hypogonadism – when present – manifests in both syndromes, in males as micropenis and/or cryptorchidism and in females as hypoplastic labia minora, clitoral hypoplasia, and small introitus.
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-2 (MMDS2) with hyperglycinemia is a severe autosomal recessive disorder characterized by developmental regression in infancy. Affected children have an encephalopathic disease course with seizures, spasticity, loss of head control, and abnormal movement. Additional more variable features include optic atrophy, cardiomyopathy, and leukodystrophy. Laboratory studies show increased serum glycine and lactate. Most patients die in childhood. The disorder represents a form of 'variant' nonketotic hyperglycinemia and is distinct from classic nonketotic hyperglycinemia (NKH, or GCE; 605899), which is characterized by significantly increased CSF glycine. Several forms of 'variant' NKH, including MMDS2, appear to result from defects of mitochondrial lipoate biosynthesis (summary by Baker et al., 2014). For a general description and a discussion of genetic heterogeneity of multiple mitochondrial dysfunctions syndrome, see MMDS1 (605711).
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).
Epilepsy, familial temporal lobe, 5
MedGen UID:
482360
Concept ID:
C3280730
Disease or Syndrome
Pyruvate dehydrogenase lipoic acid synthetase deficiency
MedGen UID:
482517
Concept ID:
C3280887
Disease or Syndrome
Hyperglycinemia, lactic acidosis, and seizures is a severe autosomal recessive disorder characterized by onset of hypotonia and seizures associated with increased serum glycine and lactate in the first days of life. Affected individuals develop an encephalopathy or severely delayed psychomotor development, which may result in death in childhood. The disorder represents a form of 'variant' nonketotic hyperglycinemia and is distinct from classic nonketotic hyperglycinemia (NKH, or GCE; 605899), which is characterized by significantly increased CSF glycine. Several forms of 'variant' NKH, including HGCLAS, appear to result from defects of mitochondrial lipoate biosynthesis (summary by Baker et al., 2014).
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
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 12
MedGen UID:
482831
Concept ID:
C3281201
Disease or Syndrome
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).
Band-like calcification with simplified gyration and polymicrogyria
MedGen UID:
483678
Concept ID:
C3489725
Disease or Syndrome
Pseudo-TORCH syndrome-1 is an autosomal recessive neurologic disorder with characteristic clinical and neuroradiologic features that mimic intrauterine TORCH infection in the absence of evidence of infection. Affected individuals have congenital microcephaly, intracranial calcifications, severe developmental delay, simplified gyration and polymicrogyria, 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. Genetic Heterogeneity of Pseudo-TORCH Syndrome See also PTORCH2 (617397), caused by mutation in the USP18 gene (607057) on chromosome 22q11.
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.
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, highly arched eyebrows, long eyelashes, short nose with anteverted nares, 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
Congenital disorder of glycosylation type 2L
MedGen UID:
766144
Concept ID:
C3553230
Disease or Syndrome
Microcephaly, short stature, and polymicrogyria with or without seizures
MedGen UID:
766745
Concept ID:
C3553831
Disease or Syndrome
Seckel syndrome 7
MedGen UID:
766784
Concept ID:
C3553870
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).
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 (zellweger)
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 4B
MedGen UID:
766851
Concept ID:
C3553937
Disease or Syndrome
Peroxisome biogenesis disorder-4B (PDB4B) includes the overlapping phenotypes of neonatal adrenoleukodystrophy (NALD) and infantile Refsum disease (IRD), which represent milder manifestations of the Zellweger syndrome spectrum (ZSS) of peroxisome biogenesis disorders (PBDs). The clinical course of patients with the NALD and IRD presentation is variable and may include developmental delay, hypotonia, liver dysfunction, sensorineural hearing loss, retinal dystrophy, and visual impairment. Children with the NALD presentation may reach their teens, and those with the IRD presentation may reach adulthood (summary by Waterham and Ebberink, 2012). For a complete phenotypic description and a discussion of genetic heterogeneity of PBD(NALD/IRD), see 601539. Individuals with mutations in the PEX6 gene have cells of complementation group 4 (CG4, equivalent to CG6 and CGC). For information on the history of PBD complementation groups, see 214100.
Peroxisome biogenesis disorder 5a (zellweger)
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.
Combined oxidative phosphorylation deficiency 11
MedGen UID:
766981
Concept ID:
C3554067
Disease or Syndrome
COXPD11 is a severe multisystemic autosomal recessive disorder characterized by neonatal hypotonia and lactic acidosis. Affected individuals may have respiratory insufficiency, foot deformities, or seizures, and all reported patients have died in infancy. Biochemical studies show deficiencies of multiple mitochondrial respiratory enzymes (summary by Garcia-Diaz et al., 2012). For a discussion of genetic heterogeneity of combined oxidative phosphorylation deficiency, see COXPD1 (609060).
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).
Pontocerebellar hypoplasia, type 7
MedGen UID:
767140
Concept ID:
C3554226
Disease or Syndrome
Pontocerebellar hypoplasia type 7 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).
Schuurs-hoeijmakers syndrome
MedGen UID:
767257
Concept ID:
C3554343
Disease or Syndrome
Schuurs-Hoeijmakers syndrome is an autosomal dominant disorder characterized by mental retardation, distinct craniofacial features, and variable additional congenital abnormalities (summary by Schuurs-Hoeijmakers et al., 2016).
Autism, susceptibility to, 18
MedGen UID:
767287
Concept ID:
C3554373
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.
Cowden syndrome 5
MedGen UID:
767432
Concept ID:
C3554518
Disease or Syndrome
Cowden syndrome 6
MedGen UID:
767433
Concept ID:
C3554519
Disease or Syndrome
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).
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.
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
X-linked mental retardation-98 is a neurodevelopmental disorder characterized by delayed psychomotor development, poor speech, behavioral abnormalities, poor overall growth, dysmorphic facial features, and often early-onset seizures. Some carrier females are unaffected, whereas other females with mutations are affected; males tend to be more severely affected than females. It is believed that the phenotypic variability and disease manifestations in female carriers results from skewed X-inactivation or cellular mosaicism (summary by de Lange et al., 2016).
Cardiofaciocutaneous syndrome 3
MedGen UID:
815336
Concept ID:
C3809006
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.
Cortical dysplasia, complex, with other brain malformations 2
MedGen UID:
815343
Concept ID:
C3809013
Disease or Syndrome
Muscular dystrophy-dystroglycanopathy (congenital with brain and eye anomalies), type a, 13
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).
Multiple congenital anomalies-hypotonia-seizures syndrome 3
MedGen UID:
815686
Concept ID:
C3809356
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). The disorder is caused by a defect in glycosylphosphatidylinositol (GPI) biosynthesis. For a discussion of genetic heterogeneity of MCAHS, see MCAHS1 (614080). For a discussion of genetic heterogeneity of GPI biosynthesis defects, see GPIBD1 (610293).
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
Hypotonia, infantile, with psychomotor retardation and characteristic facies 1
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). Genetic Heterogeneity of Infantile Hypotonia with Psychomotor Retardation and Characteristic Facies See also IHPRF2 (616801), caused by mutation in the UNC80 gene (612636) on chromosome 2q34; and IHPRF3 (616900), caused by mutation in the TBCK gene (616899) on chromosome 4q24.
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
FBXL4-related encephalomyopathic mitochondrial DNA (mtDNA) depletion syndrome is a multi-system disorder characterized primarily by congenital or early-onset lactic acidosis and growth failure, feeding difficulty, hypotonia, and global developmental delay. Other neurologic manifestations can include seizures, movement disorders, ataxia, autonomic dysfunction, and stroke-like episodes. All affected individuals alive at the time they were reported (median age: 3.5 years) demonstrated significant global developmental delay. Other findings can involve the heart (hypertrophic cardiomyopathy, congenital heart malformations, arrhythmias), liver (mildly elevated transaminases), eyes (cataract, strabismus, nystagmus, optic atrophy), hearing (sensorineural hearing loss), and bone marrow (neutropenia, lymphopenia). Survival varies; the median age of reported deaths was two years (range 2 days - 75 months), although surviving individuals as old as 36 years have been reported. To date FBXL4-related mtDNA depletion syndrome has been reported in 50 individuals.
Periventricular nodular heterotopia 6
MedGen UID:
816202
Concept ID:
C3809872
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 1w
MedGen UID:
816392
Concept ID:
C3810062
Disease or Syndrome
Polymicrogyria, bilateral perisylvian, autosomal recessive
MedGen UID:
816735
Concept ID:
C3810405
Disease or Syndrome
Autosomal recessive bilateral perisylvian polymicrogyria is characterized by strikingly restricted polymicrogyria limited to the cortex surrounding the Sylvian fissure. Affected individuals have intellectual and language difficulty and seizures, but no motor disability (Bae et al., 2014).
Cortical dysplasia, complex, with other brain malformations 5
MedGen UID:
816737
Concept ID:
C3810407
Disease or Syndrome
The tubulinopathies are a wide and overlapping range of brain malformations caused by mutation of one of seven genes encoding different isotypes of tubulin. Brain malformations include: A range of lissencephalies (classic lissencephaly, lissencephaly with cerebellar hypoplasia, lissencephaly with agenesis of the corpus callosum, and centrally predominant pachygyria), Polymicrogyria-like cortical dysplasia, Simplified gyral pattern, and Microlissencephaly often in combination with dysplastic basal ganglia, corpus callosum abnormalities, and hypoplasia or dysplasia of the brain stem and cerebellum. Clinical features include motor and intellectual disabilities, epilepsy, and ocular findings of varying severity.
Mental retardation, X-linked 100
MedGen UID:
855516
Concept ID:
C3890167
Disease or Syndrome
Pontocerebellar hypoplasia, type 9
MedGen UID:
862791
Concept ID:
C4014354
Disease or Syndrome
Pontocerebellar hypoplasia type 9 is an autosomal recessive neurodevelopmental and neurodegenerative disorder characterized by severely delayed psychomotor development, progressive microcephaly, spasticity, seizures, and brain abnormalities, including brain atrophy, thin corpus callosum, and delayed myelination (summary by Akizu et al., 2013). For a general phenotypic description and a discussion of genetic heterogeneity of PCH, see PCH1 (607596).
Mitochondrial complex III deficiency, nuclear type 7
MedGen UID:
862845
Concept ID:
C4014408
Disease or Syndrome
Mitochondrial complex III deficiency is a genetic condition that can affect several parts of the body, including the brain, kidneys, liver, heart, and the muscles used for movement (skeletal muscles). Signs and symptoms of mitochondrial complex III deficiency usually begin in infancy but can appear later.The severity of mitochondrial complex III deficiency varies widely among affected individuals. People who are mildly affected tend to have muscle weakness (myopathy) and extreme tiredness (fatigue), particularly during exercise (exercise intolerance). More severely affected individuals have problems with multiple body systems, such as liver disease that can lead to liver failure, kidney abnormalities (tubulopathy), and brain dysfunction (encephalopathy). Encephalopathy can cause delayed development of mental and motor skills (psychomotor delay), movement problems, weak muscle tone (hypotonia), and difficulty with communication. Some affected individuals have a form of heart disease called cardiomyopathy, which can lead to heart failure. Most people with mitochondrial complex III deficiency have a buildup of a chemical called lactic acid in the body (lactic acidosis). Some affected individuals also have buildup of molecules called ketones (ketoacidosis) or high blood sugar levels (hyperglycemia). Abnormally high levels of these chemicals in the body can be life-threatening.Mitochondrial complex III deficiency can be fatal in childhood, although individuals with mild signs and symptoms can survive into adolescence or adulthood.
Pontocerebellar hypoplasia, type 2e
MedGen UID:
862925
Concept ID:
C4014488
Disease or Syndrome
Pontocerebellar hypoplasia type 2E is an autosomal recessive neurodegenerative disorder characterized by profound mental retardation, progressive microcephaly, spasticity, and early-onset epilepsy (summary by Feinstein et al., 2014). For a general phenotypic description and a discussion of genetic heterogeneity of pontocerebellar hypoplasia type 2, see PCH2A (277470).
Encephalopathy, progressive, with or without lipodystrophy
MedGen UID:
863137
Concept ID:
C4014700
Disease or Syndrome
Progressive encephalopathy with or without lipodystrophy is a severe neurodegenerative disorder characterized by developmental regression of motor and cognitive skills in the first years of life, often leading to death in the first decade. Patients may show a mild or typical lipodystrophic appearance (summary by Guillen-Navarro et al., 2013).
Webb-Dattani syndrome
MedGen UID:
863145
Concept ID:
C4014708
Disease or Syndrome
Webb-Dattani syndrome is an autosomal recessive disorder characterized by frontotemporal hypoplasia, globally delayed development, and pituitary and hypothalamic insufficiency due to hypoplastic development of these brain regions. Patients present soon after birth with multiple pituitary hormonal deficiencies and subsequently develop microcephaly, seizures, and spasticity. Other features include postretinal blindness and renal abnormalities (summary by Webb et al., 2013).
Combined oxidative phosphorylation deficiency 22
MedGen UID:
863499
Concept ID:
C4015062
Disease or Syndrome
Primary autosomal recessive microcephaly 13
MedGen UID:
863517
Concept ID:
C4015080
Disease or Syndrome
Epileptic encephalopathy, early infantile, 26
MedGen UID:
863556
Concept ID:
C4015119
Disease or Syndrome
Immunodeficiency 37
MedGen UID:
863632
Concept ID:
C4015195
Disease or Syndrome
Epileptic encephalopathy, early infantile, 27
MedGen UID:
863753
Concept ID:
C4015316
Disease or Syndrome
EIEE27 is an autosomal dominant neurodevelopmental disorder characterized by delayed psychomotor development and intellectual disability of variable severity associated with early-onset seizures. Additional features may include hypotonia, abnormal movements, such as dystonia, and autistic features. Some patients may have structural malformations of cortical development on brain imaging. The phenotype is highly variable and reflects a spectrum of neurodevelopmental abnormalities that range from mild intellectual disability without seizures to an encephalopathy (summary by Platzer et al., 2017). For a general phenotypic description and a discussion of genetic heterogeneity of EIEE, see EIEE1 (308350).
Peroxisomal fatty acyl-coa reductase 1 disorder
MedGen UID:
863781
Concept ID:
C4015344
Disease or Syndrome
Peroxisomal fatty acyl-CoA reductase-1 disorder is an autosomal recessive disorder characterized by onset in infancy of severely delayed psychomotor development, growth retardation with microcephaly, and seizures. Some patients may have congenital cataracts and develop spasticity later in childhood. Biochemical studies tend to show decreased plasmalogen, consistent with a peroxisomal defect. The disorder is reminiscent of rhizomelic chondrodysplasia punctata (see, e.g., RCDP1, 215100), although the characteristic skeletal abnormalities observed in RCDP are absent (Buchert et al., 2014).
Mental retardation, autosomal dominant 31
MedGen UID:
863794
Concept ID:
C4015357
Disease or Syndrome
PURA-related neurodevelopmental disorders include PURA syndrome, caused by a heterozygous pathogenic sequence variant in PURA, and 5q31.3 deletion syndrome, caused by a genomic 5q31.3 deletion encompassing all or part of PURA.PURA-related neurodevelopmental disorders are characterized by moderate to severe neurodevelopmental delay with absence of speech in most and lack of independent ambulation in many. Early-onset problems can include hypotonia, hypothermia, hypersomnolence, feeding difficulties, excessive hiccups, recurrent central and obstructive apneas, epileptic seizures, abnormal non-epileptic movements (dystonia, dyskinesia, and dysconjugate eye movements), and abnormal vision. Congenital heart defects, urogenital malformations, skeletal abnormalities, and endocrine disorders occur, but are less common.
Epilepsy, progressive myoclonic 7
MedGen UID:
863857
Concept ID:
C4015420
Disease or Syndrome
Progressive myoclonic epilepsy-7 is a neurologic disorder characterized by onset of severe progressive myoclonus and infrequent tonic-clonic seizures in the first or second decades of life. Most patients become wheelchair-bound; some patients may have cognitive decline (summary by Muona et al., 2015). For a discussion of genetic heterogeneity of progressive myoclonic epilepsy, see EPM1A (254800).
Tenorio syndrome
MedGen UID:
864147
Concept ID:
C4015710
Disease or Syndrome
Tenorio syndrome is characterized by overgrowth, macrocephaly, and intellectual disability (ID). Some patients may have mild hydrocephaly, hypoglycemia, and inflammatory diseases resembling Sjogren syndrome (270150) (summary by Tenorio et al., 2014).
Catecholaminergic polymorphic ventricular tachycardia type 1
MedGen UID:
885877
Concept ID:
C4053736
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. The underlying cause of these episodes is the onset of fast ventricular tachycardia (bidirectional or polymorphic). Spontaneous recovery may occur 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) 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.
MEND syndrome
MedGen UID:
905986
Concept ID:
C4085243
Disease or Syndrome
Male EBP disorder with neurologic defects is an X-linked recessive disorder representing a continuous phenotypic spectrum with variable manifestations associated with a defect in sterol biosynthesis. Features include intellectual disability, short stature, scoliosis, digital abnormalities, cataracts, and dermatologic abnormalities. Not all patients show all features, and the severity is highly variable. Molecular studies indicate that affected males are hemizygous for a nonmosaic hypomorphic EBP allele. Carrier females are generally clinically asymptomatic, but may show biochemical abnormalities (summary by Arnold et al., 2012 and Barboza-Cerda et al., 2014).
Luscan-lumish syndrome
MedGen UID:
898669
Concept ID:
C4085873
Disease or Syndrome
Luscan-Lumish syndrome is characterized by macrocephaly, intellectual disability, speech delay, low sociability, and behavioral problems. More variable features include postnatal overgrowth, obesity, advanced carpal ossification, developmental delay, and seizures (Luscan et al., 2014; Lumish et al., 2015)
Mental retardation, autosomal recessive 52
MedGen UID:
903181
Concept ID:
C4225168
Disease or Syndrome
Spasticity, childhood-onset, with hyperglycinemia
MedGen UID:
905660
Concept ID:
C4225178
Disease or Syndrome
Childhood-onset spasticity with hyperglycinemia is an autosomal recessive disorder characterized by onset of slowly progressive spasticity that results in impaired gait in the first decade of life. Imaging of the central nervous system shows leukodystrophy and/or lesions in the upper spinal cord. More variable features include visual defects and mild learning disabilities. Serum glycine is increased, but CSF glycine is only mildly increased or normal; serum lactate is normal. The disorder represents a form of 'variant' nonketotic hyperglycinemia and is distinct from classic nonketotic hyperglycinemia (NKH, or GCE; 605899), which is characterized by significantly increased CSF glycine. Several forms of 'variant' NKH, including SPAHGC, appear to result from defects of mitochondrial lipoate biosynthesis (summary by Baker et al., 2014).
Microcephaly, short stature, and impaired glucose metabolism 2
MedGen UID:
906140
Concept ID:
C4225195
Disease or Syndrome
Combined oxidative phosphorylation deficiency 29
MedGen UID:
901598
Concept ID:
C4225200
Disease or Syndrome
Hyperphosphatasia with mental retardation syndrome 6
MedGen UID:
906509
Concept ID:
C4225201
Disease or Syndrome
Hyperphosphatasia with mental retardation syndrome-6 (HPMRS6) is an autosomal recessive multisystem disorder characterized by global developmental delay, dysmorphic features, seizures, and congenital cataracts. Severity is variable, and the disorder may show a range of phenotypic and biochemical abnormalities, including increased serum alkaline phosphatase levels (summary by Ilkovski et al., 2015). The disorder is caused by a defect in glycosylphosphatidylinositol (GPI) biosynthesis. For a discussion of genetic heterogeneity of HPMRS, see HPMRS1 (239300). For a discussion of genetic heterogeneity of GPI biosynthesis defects, see GPIBD1 (610293).
Skin creases, congenital symmetric circumferential, 2
MedGen UID:
902880
Concept ID:
C4225225
Congenital Abnormality
Congenital symmetric circumferential skin creases is characterized by the folding of excess skin, which leads to ringed creases, primarily of the limbs. Affected individuals also exhibit intellectual disability, cleft palate, and dysmorphic features (summary by Isrie et al., 2015). For a discussion of genetic heterogeneity of congenital symmetric circumferential skin creases, see CSCSC1 (156610).
Rhizomelic chondrodysplasia punctata type 5
MedGen UID:
900333
Concept ID:
C4225237
Disease or Syndrome
Rhizomelic chondrodysplasia punctata (RCDP) is a peroxisomal disorder characterized by disproportionately short stature primarily affecting the proximal parts of the extremities, a typical facial appearance including a broad nasal bridge, epicanthus, high-arched palate, dysplastic external ears, and micrognathia, congenital contractures, characteristic ocular involvement, dwarfism, and severe mental retardation with spasticity. Biochemically, plasmalogen synthesis and phytanic acid alpha-oxidation are defective. Most patients die in the first decade of life (summary by Wanders and Waterham, 2005). For a discussion of genetic heterogeneity of rhizomelic chondrodysplasia punctata, see 215100.
Seizures, scoliosis, and macrocephaly syndrome
MedGen UID:
909039
Concept ID:
C4225248
Disease or Syndrome
Microcephaly 16, primary, autosomal recessive
MedGen UID:
898705
Concept ID:
C4225249
Disease or Syndrome
Smith-Kingsmore syndrome
MedGen UID:
899689
Concept ID:
C4225259
Disease or Syndrome
Smith-Kingsmore syndrome is a rare autosomal dominant syndromic intellectual disability syndrome characterized by macrocephaly, seizures, umbilical hernia, and facial dysmorphic features including frontal bossing, midface hypoplasia, small chin, hypertelorism with downslanting palpebral fissures, depressed nasal bridge, smooth philtrum, and thin upper lip (Smith et al., 2013; Baynam et al., 2015).
Seizures, cortical blindness, and microcephaly syndrome
MedGen UID:
894797
Concept ID:
C4225261
Disease or Syndrome
Seizures, cortical blindness, and microcephaly syndrome (SCBMS) is an autosomal recessive neurodevelopmental disorder characterized by microcephaly, early-onset seizures, severely delayed psychomotor development, and cortical blindness. Affected individuals also tend to show poor overall growth with short stature (summary by Ercan-Sencicek et al., 2015).
Epilepsy, hearing loss, and mental retardation syndrome
MedGen UID:
895574
Concept ID:
C4225276
Disease or Syndrome
Epilepsy, hearing loss, and mental retardation syndrome is an autosomal recessive disorder characterized by severe neurologic impairment including intellectual disability, intractable epilepsy, microcephaly, abnormal muscle tone, and sensorineural hearing loss. Most affected individuals are nonambulatory, cannot sit unassisted, and have no speech development. More variable features include feeding difficulties, poor growth, cortical visual impairment, spasticity, scoliosis, immunodeficiency, and thrombocytopenia (summary by Tanaka et al., 2015).
Herpes simplex encephalitis, susceptibility to, 7
MedGen UID:
901850
Concept ID:
C4225294
Finding
Primary autosomal recessive microcephaly 15
MedGen UID:
895496
Concept ID:
C4225310
Disease or Syndrome
Hypomagnesemia, seizures, and mental retardation
MedGen UID:
906582
Concept ID:
C4225333
Disease or Syndrome
Hypomagnesemia, seizures, and mental retardation is a disorder characterized by onset of seizures associated with low serum magnesium in the first year of life. Affected individuals show variable degrees of delayed psychomotor development (summary by Arjona et al., 2014).
Epileptic encephalopathy, early infantile, 33
MedGen UID:
897930
Concept ID:
C4225337
Disease or Syndrome
Mental retardation, autosomal dominant 38
MedGen UID:
895359
Concept ID:
C4225343
Disease or Syndrome
Mental retardation, autosomal dominant 36
MedGen UID:
899880
Concept ID:
C4225352
Mental or Behavioral Dysfunction
Mental retardation, autosomal dominant 35
MedGen UID:
900298
Concept ID:
C4225354
Disease or Syndrome
PPP2R5D-related intellectual disability is a neurological disorder characterized by moderate to severe developmental delay and intellectual disability. Affected individuals have weak muscle tone (hypotonia); delayed development of motor skills, such as sitting, standing, and walking; and delayed speech development. Recurrent seizures (epilepsy) and autism spectrum disorder, which is characterized by impaired communications and social interaction, can also occur in affected individuals. Most people with PPP2R5D-related intellectual disability have an unusually large head size (macrocephaly), and some have other unusual facial features, including a prominent forehead (frontal bossing), widely spaced eyes (hypertelorism), and eyes that slant downward (downslanting palpebral fissures).
Mental retardation, X-linked, syndromic 34
MedGen UID:
902184
Concept ID:
C4225417
Mental or Behavioral Dysfunction
X-linked syndromic mental retardation-34 is an X-linked recessive neurodevelopmental disorder characterized by delayed psychomotor development, intellectual disability with poor speech, dysmorphic facial features, and mild structural brain abnormalities, including thickening of the corpus callosum (summary by Mircsof et al., 2015).
Linear skin defects with multiple congenital anomalies 3
MedGen UID:
906997
Concept ID:
C4225421
Disease or Syndrome
Neurodevelopmental disorder with hypotonia, seizures, and absent language
MedGen UID:
934610
Concept ID:
C4310643
Disease or Syndrome
Lissencephaly 8
MedGen UID:
934613
Concept ID:
C4310646
Disease or Syndrome
Lissencephaly-8 is an autosomal recessive neurologic disorder characterized by delayed psychomotor development, intellectual disability with poor or absent speech, early-onset refractory seizures, and hypotonia. Brain imaging shows variable features, including cortical gyral abnormalities and hypoplasia of the corpus callosum, brainstem, and cerebellum (summary by Jerber et al., 2016). For a general description and a discussion of genetic heterogeneity lissencephaly, see LIS1 (607432).
Immunodeficiency 49
MedGen UID:
934623
Concept ID:
C4310656
Disease or Syndrome
Combined oxidative phosphorylation deficiency 31
MedGen UID:
934628
Concept ID:
C4310661
Disease or Syndrome
Combined oxidative phosphorylation deficiency-31 is an autosomal recessive multisystem disorder characterized by left ventricular noncompaction (LVNC), global developmental delay, and severe hypotonia. More variable features include seizures, cataract, and abnormal movements. The disorder becomes apparent soon after birth or in early infancy, and patients may die in early childhood. Biochemical studies are consistent with a defect in mitochondrial function (summary by Eldomery et al., 2016). For a discussion of genetic heterogeneity of combined oxidative phosphorylation deficiency, see COXPD1 (609060).
Encephalopathy, progressive, early-onset, with brain atrophy and thin corpus callosum
MedGen UID:
934638
Concept ID:
C4310671
Disease or Syndrome
PEBAT is an autosomal recessive neurodevelopmental disorder characterized by severely delayed psychomotor development apparent soon after birth or in infancy, profound intellectual disability, poor or absent speech, and seizures. Most patients are never able to walk due to hypotonia or spasticity. Brain imaging shows cerebral and cerebellar atrophy, thin corpus callosum, and secondary hypomyelination. The disorder shows progressive features, including microcephaly, consistent with a neurodegenerative process (summary by Miyake et al., 2016; Flex et al., 2016).
Encephalopathy, progressive, early-onset, with brain edema and/or leukoencephalopathy
MedGen UID:
934642
Concept ID:
C4310675
Disease or Syndrome
Early-onset progressive encephalopathy with brain edema and/or leukoencephalopathy (PEBEL) is an autosomal recessive severe neurometabolic disorder characterized by rapidly progressive neurologic deterioration that is usually associated with a febrile illness. Affected infants tend to show normal early development followed by acute psychomotor regression with ataxia, hypotonia, respiratory insufficiency, and seizures, resulting in coma and death in the first years of life. Brain imaging shows multiple abnormalities, including brain edema and signal abnormalities in the cortical and subcortical regions (summary by Kremer et al., 2016).
Short stature, rhizomelic, with microcephaly, micrognathia, and developmental delay
MedGen UID:
934653
Concept ID:
C4310686
Disease or Syndrome
Short stature, brachydactyly, intellectual developmental disability, and seizures
MedGen UID:
934656
Concept ID:
C4310689
Disease or Syndrome
Epileptic encephalopathy, early infantile, 45
MedGen UID:
934658
Concept ID:
C4310691
Disease or Syndrome
Epileptic encephalopathy, early infantile, 44
MedGen UID:
934667
Concept ID:
C4310700
Disease or Syndrome
Epileptic encephalopathy, early infantile, 43
MedGen UID:
934679
Concept ID:
C4310712
Disease or Syndrome
Epileptic encephalopathy, early infantile, 42
MedGen UID:
934683
Concept ID:
C4310716
Disease or Syndrome
Epileptic encephalopathy, early infantile, 41
MedGen UID:
934684
Concept ID:
C4310717
Disease or Syndrome
Encephalopathy due to defective mitochondrial and peroxisomal fission 2
MedGen UID:
934693
Concept ID:
C4310726
Disease or Syndrome
Encephalopathy due to defective mitochondrial and peroxisomal fission-2 is an autosomal recessive disorder characterized by delayed psychomotor development, severe hypotonia with inability to walk, microcephaly, and abnormal signals in the basal ganglia. More variable features include early-onset seizures, optic atrophy, and peripheral neuropathy (summary by Koch et al., 2016). For a discussion of genetic heterogeneity of EMPF, see EMPF1 (614388).
Hydrops, lactic acidosis, and sideroblastic anemia
MedGen UID:
934728
Concept ID:
C4310761
Disease or Syndrome
Mental retardation, autosomal dominant 42
MedGen UID:
934741
Concept ID:
C4310774
Disease or Syndrome
Autosomal dominant mental retardation-42 is a neurodevelopmental disorder characterized by global developmental delay and intellectual disability. More variable features include hypotonia, often later associated with limb hypertonia, seizures of various types, and poor overall growth. Strabismus, cortical visual impairment, and autistic features may also be present (summary by Petrovski et al., 2016).
Spinocerebellar ataxia, autosomal recessive 23
MedGen UID:
934747
Concept ID:
C4310780
Disease or Syndrome
Autosomal recessive spinocerebellar ataxia-23 is a neurologic disorder characterized by epilepsy, intellectual disability, and gait ataxia (summary by Gomez-Herreros et al., 2014).
Dyskinesia, limb and orofacial, infantile-onset
MedGen UID:
934759
Concept ID:
C4310792
Disease or Syndrome
Infantile-onset limb and orofacial dyskinesia is an autosomal recessive neurologic disorder characterized by delayed motor development and onset of a hyperkinetic movement disorder in the first year of life. The disorder results in impaired walking and orofacial dyskinesia with difficulty talking; the severity is variable (summary by Diggle et al., 2016).
Mental retardation, autosomal recessive 53
MedGen UID:
934761
Concept ID:
C4310794
Disease or Syndrome
Autosomal recessive mental retardation-53 is a neurodevelopmental disorder characterized by severely delayed psychomotor development, hypotonia apparent since infancy, and early-onset seizures in most patients. Some patients may have additional features, such as cerebellar hypoplasia and ataxia. MRT53 is one of a group of similar neurologic disorders resulting from biochemical defects in the glycosylphosphatidylinositol (GPI) biosynthetic pathway (summary by Makrythanasis et al., 2016). For a discussion of genetic heterogeneity of GPI biosynthesis defects, see GPIBD1 (610293).
Mental retardation, X-linked, syndromic, Bain type
MedGen UID:
934781
Concept ID:
C4310814
Disease or Syndrome
MRXSB is an X-linked dominant neurodevelopmental disorder characterized by delayed psychomotor development, intellectual disability with behavioral abnormalities, and dysmorphic facial features. Additional variable features include musculoskeletal abnormalities, seizures, acquired microcephaly, and feeding problems with poor overall growth. Only females are affected (summary by Bain et al., 2016).
Mental retardation, X-linked 103
MedGen UID:
934785
Concept ID:
C4310818
Disease or Syndrome
Chromosome 11p13 deletion syndrome, distal
MedGen UID:
935014
Concept ID:
C4311047
Disease or Syndrome
Kenny-Caffey Syndrome Type 2
MedGen UID:
1373312
Concept ID:
C4316787
Disease or Syndrome
An autosomal dominant form of Kenny-Caffey Syndrome due to mutation(s) in the FAM111A gene, encoding protein FAM111A. This condition is characterized by transient hypocalcemia, delayed closure of the anterior fontanel, eye anomalies, including microphthalmia, proportionate short stature, and cortical thickening and medullary stenosis of the tubular bones.
EPILEPTIC ENCEPHALOPATHY, EARLY INFANTILE, 54
MedGen UID:
1392637
Concept ID:
C4479319
Disease or Syndrome
NEURODEVELOPMENTAL DISORDER WITH EPILEPSY, CATARACTS, FEEDING DIFFICULTIES, AND DELAYED BRAIN MYELINATION
MedGen UID:
1377894
Concept ID:
C4479333
Disease or Syndrome
COG2-CDG
MedGen UID:
1390458
Concept ID:
C4479353
Disease or Syndrome
Gangliosidosis GM1 type 3
MedGen UID:
78655
Concept ID:
C0268273
Disease or Syndrome
GLB1-related disorders comprise two phenotypically distinct lysosomal storage disorders: GM1 gangliosidosis and mucopolysaccharidosis type IVB (MPS IVB). GM1 gangliosidosis includes phenotypes that range from severe to mild. Type I (infantile) begins before age one year; progressive central nervous system dysfunction leads to spasticity, deafness, blindness, and decerebrate rigidity. Life expectancy is two to three years. Type II can be subdivided into the late-infantile form and juvenile form. Type II, late-infantile form begins between ages one and three years; life expectancy is five to ten years. Type II, juvenile form begins between ages three and ten years with insidious plateauing of motor and cognitive development followed by slow regression. Type II may or may not include skeletal dysplasia. Type III begins in the second to third decade with extrapyramidal signs, gait disturbance, and cardiomyopathy; and can be misidentified as Parkinson disease. Intellectual impairment is common late in the disease; skeletal involvement includes short stature, kyphosis, and scoliosis of varying severity. MPS IVB is characterized by skeletal changes, including short stature and skeletal dysplasia. Affected children have no distinctive clinical findings at birth. The severe form is usually apparent between ages one and three years, and the attenuated form in late childhood or adolescence. In addition to skeletal involvement, significant morbidity can result from respiratory compromise, obstructive sleep apnea, valvular heart disease, hearing impairment, corneal clouding, and spinal cord compression. Intellect is normal unless spinal cord compression leads to central nervous system compromise.
Neurofaciodigitorenal syndrome
MedGen UID:
163212
Concept ID:
C0796088
Disease or Syndrome
Hypotonia-cystinuria syndrome
MedGen UID:
341133
Concept ID:
C1848030
Disease or Syndrome