Congenital sensory neuropathy with selective loss of small myelinated fibers.

The results of clinical, electrophysiological, autonomic, and histopathological studies in a 6-year-old patient with congenital sensory neuropathy are presented. Selective loss of pain perception affecting the extremities was noted from infancy. Nerve conduction studies were normal. Small myelinated fibers were selectively reduced in the sural nerve, and unmyelinated fibers were normal.