Congenital neuropathy with the absence of large myelinated fibers.

Twelve patients with hereditary motor and sensory neuropathy with the absence of large myelinated fibers have been reported. All of these patients had central nervous system involvement. In this report, we describe the first patient with pure motor and sensory neuropathy with the absence of large myelinated fibers without central nervous system involvement. Morphometric analysis of the biopsied sural nerve specimen revealed extremely small myelinated fibers compared with previously reported patients. It is supposed that the cause of this disease might be the abnormal development of axons of the peripheral nerves.