spinal muscular atrophy

2nd most common autosomal recessive disease in Caucasians

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

James Lowe, DM BM BS MRCPath - 13 November 1997
Last updated: 1 October 2013