Non-familial, spinal segmental muscular atrophy in juvenile and young subjects.

Thirty-two cases of juvenile and adult onset, non-familial, spinal, segmental muscular atrophy seen in two widely separated geographical regions of India were studied over the last 15 years. The characteristic features were: the non-familial, non-endemic nature, the strictly segmental distribution from the clinical and EMG point of view, which involved either distal or proximal segments of one upper or lower extremity, the absence of involvement of cranial nerves of the pyramidal, sensory and autonomic nervous system, the very high male predilection and the very insidious progression. No definitive etiological factors could be incriminated.