Spinal muscular atrophy (SMA) is the most common genetic neurodegenerative disease leading to death in childhood. SMA is characterized by the loss of spinal cord anterior horn neurons and progressive denervation of skeletal muscles. SMA is caused by deletion or mutation of the telomeric copy of human survival motor neuron gene 1 (hSMN1) and retention of the hSMN2 gene. SMA animal models are extremely useful in studying the mechanism of SMA-related motoneuronal death, and may provide an in vivo system for testing a potential SMA therapy
