What is the prognosis of spinal muscular atrophy (SMA)?

Updated: Apr 28, 2014
  • Author: Hidehiro Takei, MD; Chief Editor: Adekunle M Adesina, MD, PhD  more...
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The mortality and morbidity of spinal muscular atrophy (SMA) are inversely correlated with the age at onset. In type I SMA, because bulbar and respiratory muscles become affected rapidly, two thirds of patients expire within the first 2 years. In type II SMA, survival into adolescence or adulthood is common. In type III SMA, the life expectancy is close to that of the normal population.

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