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Items: 1 to 20 of 33

1.

Epileptic encephalopathy, early infantile, 42

MedGen UID:
934683
Concept ID:
C4310716
Disease or Syndrome
2.

Mitochondrial DNA depletion syndrome 12a (cardiomyopathic type), autosomal dominant

MTDPS12A is characterized by severe hypotonia due to mitochondrial dysfunction apparent at birth. Affected infants have respiratory insufficiency requiring mechanical ventilation and have poor or no motor development. Many die in infancy, and those that survive have profound hypotonia with significant muscle weakness and inability to walk independently. Some patients develop hypertrophic cardiomyopathy. Muscle samples show mtDNA depletion and severe combined mitochondrial respiratory chain deficiencies (summary by Thompson et al., 2016). For a discussion of genetic heterogeneity of mtDNA depletion syndromes, see MTDPS1 (603041). [from GTR]

MedGen UID:
934643
Concept ID:
C4310676
Disease or Syndrome
3.

Myasthenic syndrome, congenital, 21, presynaptic

MedGen UID:
934621
Concept ID:
C4310654
Disease or Syndrome
4.

Myasthenic syndrome, congenital, 18

Congenital myasthenic syndromes (designated as CMS throughout this entry) are characterized by fatigable weakness of skeletal muscle (e.g., ocular, bulbar, limb muscles) with onset at or shortly after birth or in early childhood; rarely, symptoms may not manifest until later in childhood. Cardiac and smooth muscle are usually not involved. Severity and course of disease are highly variable, ranging from minor symptoms to progressive disabling weakness. In some subtypes of CMS, myasthenic symptoms may be mild, but sudden severe exacerbations of weakness or even sudden episodes of respiratory insufficiency may be precipitated by fever, infections, or excitement. Major findings of the neonatal-onset subtype include: respiratory insufficiency with sudden apnea and cyanosis; feeding difficulties; poor suck and cry; choking spells; eyelid ptosis; and facial, bulbar, and generalized weakness. Arthrogryposis multiplex congenita may also be present. Stridor in infancy may be an important clue to CMS. Later childhood-onset subtypes show abnormal muscle fatigability with difficulty in activities such as running or climbing stairs; motor milestones may be delayed; fluctuating eyelid ptosis and fixed or fluctuating extraocular muscle weakness are common presentations. [from GTR]

MedGen UID:
906793
Concept ID:
C4225364
Disease or Syndrome
5.

Epileptic encephalopathy, early infantile, 31

MedGen UID:
894942
Concept ID:
C4225357
Disease or Syndrome
6.

Generalized epilepsy with febrile seizures plus, type 9

Generalized epilepsy with febrile seizures plus-9 is an autosomal dominant neurologic disorder characterized by onset of febrile and/or afebrile seizures in early childhood, usually before age 3 years. Seizure types are variable and include generalized tonic-clonic, atonic, myoclonic, complex partial, and absence. Most patients have remission of seizures later in childhood with no residual neurologic deficits, but rare patients may show mild developmental delay or mild intellectual disabilities (summary by Schubert et al., 2014). For a general phenotypic description and a discussion of genetic heterogeneity of GEFS+, see 604233. [from GTR]

MedGen UID:
863832
Concept ID:
C4015395
Disease or Syndrome
7.

Mitochondrial DNA depletion syndrome 12b (cardiomyopathic type), autosomal recessive

Mitochondrial DNA depletion syndrome-12B is an autosomal recessive mitochondrial disorder characterized by childhood onset of slowly progressive hypertrophic cardiomyopathy and generalized skeletal myopathy resulting in exercise intolerance and, in some patients, muscle weakness and atrophy. Skeletal muscle biopsy shows ragged red fibers, mtDNA depletion, and accumulation of abnormal mitochondria (summary by Echaniz-Laguna et al., 2012). For a discussion of genetic heterogeneity of mtDNA depletion syndromes, see MTDPS1 (603041). [from GTR]

MedGen UID:
815773
Concept ID:
C3809443
Disease or Syndrome
8.

Lethal congenital contracture syndrome 5

MedGen UID:
815602
Concept ID:
C3809272
Disease or Syndrome
9.

Alternating hemiplegia of childhood 1

Alternating hemiplegia of childhood is a rare syndrome of episodic hemi- or quadriplegia lasting minutes to days. Most cases are accompanied by dystonic posturing, choreoathetoid movements, nystagmus, other ocular motor abnormalities, autonomic disturbances, and progressive cognitive impairment (Mikati et al., 1992). The disorder may mimic or overlap with other disorders, including familial hemiplegic migraine (FHM1; 141500) and GLUT1 deficiency syndrome (606777) (Rotstein et al., 2009). Genetic Heterogeneity of Alternating Hemiplegia of Childhood See also AHC2 (614820), caused by mutation in the ATP1A3 gene (182350). [from GTR]

MedGen UID:
762361
Concept ID:
C3549447
Disease or Syndrome
10.

Dystonia 23

MedGen UID:
761274
Concept ID:
C3538999
Disease or Syndrome
11.

Encephalopathy due to defective mitochondrial and peroxisomal fission 1

Encephalopathy due to defective mitochondrial and peroxisomal fission-1 is characterized by delayed psychomotor development and hypotonia that may lead to death in childhood. Many patients develop refractory seizures, consistent with an epileptic encephalopathy, and thereafter show neurologic decline. The age at onset, features, and severity are variable, and some patients may not have clinical evidence of mitochondrial or peroxisomal dysfunction (summary by Sheffer et al., 2016; Fahrner et al., 2016). Genetic Heterogeneity of Encephalopathy Due to Defective Mitochondrial And Peroxisomal Fission See also EMPF2 (617086), caused by mutation in the MFF gene (614785) on chromosome 2q36. [from GTR]

MedGen UID:
482290
Concept ID:
C3280660
Disease or Syndrome
12.

Early infantile epileptic encephalopathy 4

STXBP1 encephalopathy with epilepsy is characterized by early-onset encephalopathy with epilepsy (i.e., moderate to severe intellectual disability, refractory seizures, and ongoing epileptiform activity). The median age of onset of seizures is six weeks (range 1 day to 13 years). Seizure types can include infantile spasms; generalized tonic-clonic, clonic, or tonic seizures; and myoclonic, focal, atonic, and absence seizures. Epilepsy syndromes can include Ohtahara syndrome, West syndrome, Lennox-Gaustaut syndrome, and Dravet syndrome (not SCN1A-related), classic Rett syndrome (not MECP2-related), and atypical Rett syndrome (not CDKL5-related). The EEG is characterized by focal epileptic activity, burst suppression, hypsarrhythmia, or generalized spike-and-slow waves. Other findings can include abnormal tone, movement disorders (especially ataxia and dystonia), and behavior disorders (including autism spectrum disorder). Feeding difficulties are common. [from GTR]

MedGen UID:
436917
Concept ID:
C2677326
Disease or Syndrome
13.

Mental retardation, X-linked 96

MedGen UID:
411731
Concept ID:
C2749021
14.

4p partial monosomy syndrome

Wolf-Hirschhorn syndrome (WHS) is characterized by typical craniofacial features in infancy consisting of ‘Greek warrior helmet’ appearance of the nose (wide bridge of the nose continuing to the forehead), microcephaly, high anterior hairline with prominent glabella, widely spaced eyes, epicanthus, highly arched eyebrows, short philtrum, downturned corners of the mouth, micrognathia, and poorly formed ears with pits/tags. All affected individuals have prenatal-onset growth deficiency followed by postnatal growth retardation and hypotonia with muscle underdevelopment. Developmental delay/intellectual disability of variable degree is present in all. Seizures occur in 90% to 100% of children with WHS. Other findings include skeletal anomalies (60%-70%), congenital heart defects (~50%), hearing loss (mostly conductive) (>40%), urinary tract malformations (25%), and structural brain abnormalities (33%). [from GTR]

MedGen UID:
408255
Concept ID:
C1956097
Disease or Syndrome
15.

Episodic ataxia, type 6

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. [from GTR]

MedGen UID:
390739
Concept ID:
C2675211
Disease or Syndrome
16.

Optic atrophy 5

OPA5 is an autosomal dominant form of nonsyndromic optic atrophy, manifest as slowly progressive visual loss with variable onset from the first to third decades. Additional ocular abnormalities may include central scotoma and color vision defects. The pathogenesis is related to defective mitochondrial fission (summary by Gerber et al., 2017). For a discussion of genetic heterogeneity of optic atrophy, see OPA1 (165500). [from GTR]

MedGen UID:
377837
Concept ID:
C1853139
Disease or Syndrome
17.

Ceroid lipofuscinosis neuronal 8

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. [from GTR]

MedGen UID:
374004
Concept ID:
C1838570
Disease or Syndrome
18.

Familial hemiplegic migraine type 2

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. [from GTR]

MedGen UID:
355962
Concept ID:
C1865322
Disease or Syndrome
19.

Ceroid lipofuscinosis, neuronal, 8, northern epilepsy variant

The neuronal ceroid lipofuscinoses (NCL; CLN) are a clinically and genetically heterogeneous group of neurodegenerative disorders characterized by the intracellular accumulation of autofluorescent lipopigment storage material in different patterns ultrastructurally. The lipopigment patterns observed most often in CLN8 comprise mixed combinations of 'granular,' 'curvilinear,' and 'fingerprint' profiles (Mole et al., 2005). For a general phenotypic description and a discussion of genetic heterogeneity of CLN, see CLN1 (256730). [from GTR]

MedGen UID:
355328
Concept ID:
C1864923
Disease or Syndrome
20.

Cone-rod dystrophy 7

Cone-rod dystrophy is a group of related eye disorders that causes vision loss, which becomes more severe over time. These disorders affect the retina, which is the layer of light-sensitive tissue at the back of the eye. In people with cone-rod dystrophy, vision loss occurs as the light-sensing cells of the retina gradually deteriorate.The first signs and symptoms of cone-rod dystrophy, which often occur in childhood, are usually decreased sharpness of vision (visual acuity) and increased sensitivity to light (photophobia). These features are typically followed by impaired color vision (dyschromatopsia), blind spots (scotomas) in the center of the visual field, and partial side (peripheral) vision loss. Over time, affected individuals develop night blindness and a worsening of their peripheral vision, which can limit independent mobility. Decreasing visual acuity makes reading increasingly difficult and most affected individuals are legally blind by mid-adulthood. As the condition progresses, individuals may develop involuntary eye movements (nystagmus).There are more than 30 types of cone-rod dystrophy, which are distinguished by their genetic cause and their pattern of inheritance: autosomal recessive, autosomal dominant, and X-linked. Additionally, cone-rod dystrophy can occur alone without any other signs and symptoms or it can occur as part of a syndrome that affects multiple parts of the body. [from GTR]

MedGen UID:
355026
Concept ID:
C1863634
Disease or Syndrome
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