MR findings of spinal muscular atrophy Type II: sibling cases.

We present magnetic resonance (MR) findings of siblings affected by spinal muscular atrophy (SMA) Type II. MRI of their thighs showed severe muscle atrophy and fatty infiltration. Selective preservation of the adductor longus muscle, the gracilis muscle, and the sartorius muscles was observed, suggesting a characteristic finding of SMA Type II. These findings were more severe in the older patient.