spinal muscular atrophy CHORUS

Description: spinal muscular atrophy. Notes and links to radiology illustrations
2nd most common autosomal recessive disease in Caucasians
* pathology
  o degeneration of the spinal anterior horn cells
  o atrophy and wasting of skeletal muscles
* types
  o SMA I = Werdnig-Hoffman disease: rapidly progressive
  o SMA II = intermediate form
  o SMA III = Kugelberg-Welander disease: slowly progressive
  o uncommon adult forms
* usual presentations
  o floppy baby
  o arthrogryposis
  o muscle weakness in infancy
* diagnosis
  o weakness and wasting with areflexia
  o electrophysiology shows anterior horm
cell disease
* genetics
  o linked to chromosome 5q.
  o neuronal apoptosis inhibitory protein (NAIP) gene
  o survival motor neuron (SMN) gene