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last update : 06-06-2018
Symbol CASMN
Location 4q27
Name cerebellar atrophy and spinal motoneuronopathy
Corresponding gene EXOSC9
Other symbol(s) PCH1D
Main clinical features
  • during pregnancy, reduced fetal movements, growth retardation, and oligohydramnios
  • early-onset progressive axonal motor neuronopathy, resulting in severe weakness and respiratory impairment, in combination with cerebellar atrophy
  • arthrogryposis multiplex congenita with hip and hand involvement, severe hypotonia, and respiratory insufficiency
  • electromyography (EMG) and nerve conduction responses were consistent with an axonal motor neuronopathy
  • at brain MRI, cerebellar atrophy
  • at muscle biopsy, abundant, very small fibers, often in groups and intermixed with hypertrophic fibers, consistent with denervation and thus suggestive of a neurogenic process
  • Genetic determination autosomal recessive
    Function/system disorder neuromuscular
    Type disease
    Remark(s) . EXOSC9 variants affect likely the degradation of AU-rich transcripts, which is one of the best-known functions of the exosome in the cytosol (PMID: 29463687))