Sneddon syndrome- 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).
Spinocerebellar ataxia type 1- MedGen UID:
- 155703
- •Concept ID:
- C0752120
- •
- Disease or Syndrome
Spinocerebellar ataxia type 1 (SCA1) is characterized by progressive cerebellar ataxia, dysarthria, and eventual deterioration of bulbar functions. Early in the disease, affected individuals may have gait disturbance, slurred speech, difficulty with balance, brisk deep tendon reflexes, hypermetric saccades, nystagmus, and mild dysphagia. Later signs include slowing of saccadic velocity, development of upgaze palsy, dysmetria, dysdiadochokinesia, and hypotonia. In advanced stages, muscle atrophy, decreased deep tendon reflexes, loss of proprioception, cognitive impairment (e.g., frontal executive dysfunction, impaired verbal memory), chorea, dystonia, and bulbar dysfunction are seen. Onset is typically in the third or fourth decade, although childhood onset and late-adult onset have been reported. Those with onset after age 60 years may manifest a pure cerebellar phenotype. Interval from onset to death varies from ten to 30 years; individuals with juvenile onset show more rapid progression and more severe disease. Anticipation is observed. An axonal sensory neuropathy detected by electrophysiologic testing is common; brain imaging typically shows cerebellar and brain stem atrophy.
Charcot-Marie-Tooth disease type 4D- MedGen UID:
- 371304
- •Concept ID:
- C1832334
- •
- Disease or Syndrome
Charcot-Marie-Tooth disease type 4D (CMT4D) is an autosomal recessive disorder of the peripheral nervous system characterized by early-onset distal muscle weakness and atrophy, foot deformities, and sensory loss affecting all modalities. Affected individuals develop deafness by the third decade of life (summary by Okamoto et al., 2014).
For a phenotypic description and a discussion of genetic heterogeneity of autosomal recessive Charcot-Marie-Tooth disease, see CMT4A (214400).
Charcot-Marie-Tooth disease type 2B- MedGen UID:
- 371512
- •Concept ID:
- C1833219
- •
- Disease or Syndrome
A severe form of axonal Charcot-Marie-Tooth disease, a peripheral sensorimotor neuropathy. Onset in the second or third decade has manifestations of ulceration and infection of the feet. Symmetric and distal weakness develops mostly in the legs together with a severe symmetric distal sensory loss. Tendon reflexes are only reduced at ankles and foot deformities including pes cavus or planus and hammer toes, appear in childhood.
Charcot-Marie-Tooth disease, axonal, with vocal cord paresis, autosomal recessive- MedGen UID:
- 375113
- •Concept ID:
- C1843183
- •
- Disease or Syndrome
Autosomal recessive axonal Charcot-Marie-Tooth disease with vocal cord paresis is a severe progressive motor and sensory neuropathy with neonatal or infantile onset of weakness and wasting of the feet with subsequent involvement of the hands. Some patients develop a hoarse voice and vocal cord paresis by the second decade. Nerve conduction velocities and pathologic pattern are consistent with an axonal neuropathy (Sevilla et al., 2003).
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 before the molecular basis was known. POLG-related disorders can therefore be considered an overlapping spectrum of disease presenting from early childhood to late adulthood. The age of onset broadly correlates with the clinical phenotype. In individuals with early-onset disease (prior to age 12 years), liver involvement, feeding difficulties, seizures, hypotonia, and muscle weakness are the most common clinical features. This group has the worst prognosis. In the juvenile/adult-onset form (age 12-40 years), disease is typically characterized by peripheral neuropathy, ataxia, seizures, stroke-like episodes, and, in individuals with longer survival, progressive external ophthalmoplegia (PEO). This group generally has a better prognosis than the early-onset group. Late-onset disease (after age 40 years) is characterized by ptosis and PEO, with additional features such as peripheral neuropathy, ataxia, and muscle weakness. This group overall has the best prognosis.
Mitochondrial DNA depletion syndrome 6 (hepatocerebral type)- MedGen UID:
- 338045
- •Concept ID:
- C1850406
- •
- Disease or Syndrome
MPV17-related mitochondrial DNA (mtDNA) maintenance defect presents in the vast majority of affected individuals as an early-onset encephalohepatopathic (hepatocerebral) disease that is typically associated with mtDNA depletion, particularly in the liver. A later-onset neuromyopathic disease characterized by myopathy and neuropathy, and associated with multiple mtDNA deletions in muscle, has also rarely been described. MPV17-related mtDNA maintenance defect, encephalohepatopathic form is characterized by: Hepatic manifestations (liver dysfunction that typically progresses to liver failure, cholestasis, hepatomegaly, and steatosis); Neurologic involvement (developmental delay, hypotonia, microcephaly, and motor and sensory peripheral neuropathy); Gastrointestinal manifestations (gastrointestinal dysmotility, feeding difficulties, and failure to thrive); and Metabolic derangements (lactic acidosis and hypoglycemia). Less frequent manifestations include renal tubulopathy, nephrocalcinosis, and hypoparathyroidism. Progressive liver disease often leads to death in infancy or early childhood. Hepatocellular carcinoma has been reported.
Spinocerebellar ataxia, autosomal recessive, with axonal neuropathy 2- MedGen UID:
- 340052
- •Concept ID:
- C1853761
- •
- Disease or Syndrome
Ataxia with oculomotor apraxia type 2 (AOA2) is characterized by onset of ataxia between age three and 30 years after initial normal development, axonal sensorimotor neuropathy, oculomotor apraxia, cerebellar atrophy, and elevated serum concentration of alpha-fetoprotein (AFP).
Giant axonal neuropathy 2- MedGen UID:
- 400593
- •Concept ID:
- C1864695
- •
- Disease or Syndrome
Giant axonal neuropathy-2 is an autosomal dominant peripheral axonal neuropathy characterized by onset of distal sensory impairment and lower extremity muscle weakness and atrophy after the second decade. Foot deformities may be present in childhood. More severely affected individuals may develop cardiomyopathy. Sural nerve biopsy shows giant axonal swelling with neurofilament accumulation (summary by Klein et al., 2014).
Hereditary spastic paraplegia 17- MedGen UID:
- 419034
- •Concept ID:
- C2931276
- •
- Disease or Syndrome
The spectrum of BSCL2-related neurologic disorders includes Silver syndrome and variants of Charcot-Marie-Tooth neuropathy type 2, distal hereditary motor neuropathy (dHMN) type V, and spastic paraplegia 17. Features of these disorders include onset of symptoms ranging from the first to the seventh decade, slow disease progression, upper motor neuron involvement (gait disturbance with pyramidal signs ranging from mild to severe spasticity with hyperreflexia in the lower limbs and variable extensor plantar responses), lower motor neuron involvement (amyotrophy of the peroneal muscles and small muscles of the hand), and pes cavus and other foot deformities. Disease severity is variable among and within families.
Hereditary spastic paraplegia 55- MedGen UID:
- 761342
- •Concept ID:
- C3539506
- •
- Disease or Syndrome
A rare complex type of hereditary spastic paraplegia with characteristics of childhood onset of progressive spastic paraplegia associated with optic atrophy (with reduced visual acuity and central scotoma), ophthalmoplegia, reduced upper-extremity strength and dexterity, muscular atrophy in the lower extremities and sensorimotor neuropathy. Caused by mutations in the C12ORF65 gene (12q24.31) encoding probable peptide chain release factor C12ORF65, mitochondrial.
Charcot-Marie-Tooth disease, axonal, type 2EE- MedGen UID:
- 1677426
- •Concept ID:
- C5193076
- •
- Disease or Syndrome
Charcot-Marie-Tooth disease type 2EE (CMT2EE) is an autosomal recessive sensorimotor peripheral axonal neuropathy with onset in the first or second decades of life. The disorder primarily affects the lower limbs and is slowly progressive, sometimes resulting in loss of ambulation, with later onset of upper limb involvement. There is significant distal muscle weakness and atrophy, usually with foot or hand deformities. Skeletal muscle biopsy shows findings of disturbed mitochondrial maintenance. Cognition is unaffected, and chronic liver disease is absent (summary by Baumann et al., 2019).
For a phenotypic description and a discussion of genetic heterogeneity of axonal CMT type 2, see CMT2A (118210).
Neuropathy, hereditary sensory and autonomic, type 1A- MedGen UID:
- 1716450
- •Concept ID:
- C5235211
- •
- Disease or Syndrome
SPTLC1-related hereditary sensory neuropathy (HSN) is an axonal form of hereditary motor and sensory neuropathy distinguished by prominent early sensory loss and later positive sensory phenomena including dysesthesia and characteristic "lightning" or "shooting" pains. Loss of sensation can lead to painless injuries, which, if unrecognized, result in slow wound healing and subsequent osteomyelitis requiring distal amputations. Motor involvement is present in all advanced cases and can be severe. After age 20 years, the distal wasting and weakness may involve proximal muscles, possibly leading to wheelchair dependency by the seventh or eighth decade. Sensorineural hearing loss is variable.
46,XY gonadal dysgenesis-motor and sensory neuropathy syndrome- MedGen UID:
- 1727162
- •Concept ID:
- C5436061
- •
- Disease or Syndrome
46,XY gonadal dysgenesis-motor and sensory neuropathy syndrome is a rare, genetic, developmental defect during embryogenesis disorder characterized by partial (unilateral testis, persistence of Müllerian duct structures) or complete (streak gonads only) gonadal dysgenesis, usually manifesting with primary amenorrhea in individuals with female phenotype but 46,XY karyotype, and sensorimotor dysmyelinating minifascicular polyneuropathy, which presents with numbness, weakness, exercise-induced muscle cramps, sensory disturbances and reduced/absent deep tendon reflexes. Germ cell tumors (seminoma, dysgerminoma, gonadoblastoma) may develop from the gonadal tissue.
Charcot-Marie-Tooth disease axonal type 2Z- MedGen UID:
- 1800448
- •Concept ID:
- C5569025
- •
- Disease or Syndrome
Charcot-Marie-Tooth disease type 2Z (CMT2Z) is an autosomal dominant axonal peripheral neuropathy characterized by onset, usually in the first decade, of distal lower limb muscle weakness and sensory impairment. The disorder is progressive, and affected individuals tend to develop upper limb and proximal muscle involvement in an asymmetric pattern, resulting in severe disability late in adulthood. Rare occurrence of global developmental delay with impaired intellectual development or learning difficulties has been observed. In some instances, the same mutation may result in different phenotypic manifestations (CMT2Z or DIGFAN), which highlights the clinical spectrum associated with MORC2 mutations and may render the classification of patients into one or the other disorder challenging (summary by Sevilla et al., 2016, Ando et al., 2017, Guillen Sacoto et al., 2020).
For a phenotypic description and a discussion of genetic heterogeneity of axonal CMT, see CMT2A1 (118210).
Charcot-Marie-Tooth disease type 2Y- MedGen UID:
- 1800449
- •Concept ID:
- C5569026
- •
- Disease or Syndrome
Charcot-Marie-Tooth disease type 2Y is an autosomal dominant peripheral neuropathy characterized by distal muscle weakness and atrophy associated with length-dependent sensory loss. Most patients have involvement of both the lower and upper limbs. The age at onset and the severity of the disorder are highly variable (summary by Gonzalez et al., 2014).
For a phenotypic description and a discussion of genetic heterogeneity of axonal CMT, see CMT2A1 (118210).