Spinal Muscular Atrophy

Spinal muscular atrophy (SMA) is an autosomal recessively inherited neurodegenerative disease characterized by motor neuron cell loss and muscle weakness and atrophy. SMA is the most frequent monogenic cause of infant mortality. The incidence ranges from 1 in 6000 to 1 in 10,000 live births in all ethnic populations that have been investigated. As SMA is caused by a reduction in SMN protein levels, understanding the molecular functions of the survival motor neuron (SMN) protein can provide insights into SMA pathogenic mechanisms and potential therapeutic targets. The disease course of SMA is unusual among the neurodegenerative diseases because a rapid disease onset is often followed by symptom stabilization. Cell replacement in SMA became a possible route of treatment when embryonic stem (ES) cells were first successfully converted to motor neurons via neural stem cell intermediates.