Spinal muscular atrophies (SMA) are characterized by degeneration of lower motor 
neurons associated with muscle paralysis and atrophy. Childhood SMA is a 
frequent recessive autosomal disorder and represents one of the most common 
genetic causes of death in childhood. Mutations of the SMN1 gene are responsible 
for SMA. The knowledge of the genetic basis of SMA, a better understanding of 
SMN function, and the recent generation of SMA mouse models represent major 
advances in the field of SMA. These are starting points towards understanding 
the pathophysiology of SMA and developing therapeutic strategies for this 
devastating neurodegenerative disease, for which no curative treatment is known 
so far.