[Spinal muscular atrophies in the adult].

Spinal muscular atrophies are heterogeneous group. The diagnostic process should be careful to uncover the main differential diagnoses and to identify familial cases. Clinical phenotype is highly variable. In familial ALS cases with SOD1 mutation, the clinical scene may mimic spinal muscular atrophy. A careful questionning and a complete electroneuromyographic exam are warranted to allow the neurologist to choose among more invasive investigations for differential and positive diagnosis such as MRI, nerve or muscle biopsy, genetic analysis.