What causes spinal muscular atrophy (SMA)?

Updated: Apr 28, 2014
  • Author: Hidehiro Takei, MD; Chief Editor: Adekunle M Adesina, MD, PhD  more...
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Type I-III spinal muscular atrophy (SMA) is caused by alterations in the survival motor neuron gene (SMN). This gene becomes active in the healthy, mature fetus and functions in the stabilization of the neuronal population. In the absence of SMN, there is continued programmed cell death.

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