Which physical findings are characteristic of spinal muscular atrophy (SMA) type II - chronic infantile form?

Updated: May 29, 2019
  • Author: Jeffrey Rosenfeld, MD, PhD, FAAN; Chief Editor: Stephen L Nelson, Jr, MD, PhD, FAACPDM, FAAN, FAAP  more...
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Infants cannot get to a sitting position on their own, though they may stay upright if placed in that position.

As with SMA type I, SMA type II cause notable, symmetric proximal weakness, hypotonia, and fasciculations.

Findings on sensory examination are normal, and long-tract signs are absent. When the patient's hands are held out, a characteristic fine postural tremor may be observed.

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