Spinal Muscular Atrophy

Abstract

Spinal muscular atrophy (SMA) is a lower motor neuron disorder characterized by degeneration of the anterior horn cells in the spinal cord and bulbar motor nuclei. The clinical hallmarks of the disorder are symmetric muscle weakness and atrophy of limb muscles with variable bulbar involvement and tremor and supporting electrophysiologic and pathologic evidence of motor denervation.The most common form of the disorder is linked to chromosome 5q13 and inherited in an autosomal recessive fashion. About 96% of patients with a classic presentation have a homozygous deletion of the telomeric copy of the survival motor neuron gene on chromosome 5q. In the Western world, acute SMA is the most common..