Spastic paraplegia with neurogenic amyotrophy manifesting ballooned axons in sural nerve.

A 21-year-old man had progressive symmetric, distal muscle atrophy and weakness, as well as spasticity of the limbs. Histologic examination of the sural nerve disclosed swollen axons containing membranous tubular profiles, ring tubules, large mitochondria with abnormal cristae, and glycogen like granules. Peripheral sensory nerve fibers also were affected. The pathologic features of the peripheral nerves were similar to those of infantile neuroaxonal dystrophy. Sural nerve biopsy may be useful in the study of pathologic processes in spastic paraplegia.