Neurophysiologic studies of the peripheral nervous system in nephropathic cystinosis

M. R. Swenson, S. Rimmer, J. A. Schneider, R. B. Melles, D. A. Trauner and B. Katz
Department of Neurosciences, University of California, School of Medicine, San Diego.

Cystinosis is an autosomal recessive metabolic disorder in which nonprotein cystine accumulates within most body tissues due to a defect in lysosomal cystine transport. Neurologic declarations are only recently being recognized. We studied 13 cystinotic subjects (aged 5 to 21 years old), determining median motor and sensory nerve conduction velocities, F waves, peroneal motor nerve conduction velocities, sural sensory nerve conduction velocities, median sympathetic skin response, electrocardiogram R-to-R variability, and blink reflex analysis. The results were normal. We conclude that neurophysiologic testing suggests relative sparing of the peripheral nervous system in nephropathic cystinosis.