Which clinical history findings are characteristic of spinal muscular atrophy (SMA) type II?

Updated: Apr 28, 2014
  • Author: Hidehiro Takei, MD; Chief Editor: Adekunle M Adesina, MD, PhD  more...
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The onset of type II SMA is before the age of 18 months. There may be some overlap with type I SMA, but the median age of onset is generally later than in type I. The clinical course of type II SMA is marked by periods of apparent arrest in clinical progression. Patients are able to sit independently, but they are never able to walk unaided. Spine deformities and contractures of all major joints often develop.

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