[A pedigree of Charcot-Marie-Tooth disease type 4F (Periaxin mutation)]

We report a 51-year-old man genetically diagnosed as Charcot-Marie-Tooth disease type 4F. The patient was the first child of healthy, consanguineous parents. He had two sisters and one of them showed similar but milder symptoms. He had gait disturbance since childhood. Then he noticed muscle weakness of his hands at the age of early forties, and more difficulties in gait at the age of late forties. On examination at age 51, he showed absence of all deep tendon reflexes, weakness of the hand and distal leg muscles, pes cavus and decreased sensitivity to touch and vibration in the lower extremities. Electrophysiological studies of the median nerve showed delayed motor nerve conduction velocity and undetectable sensory nerve action potentials. The histology of his sural nerve revealed moderate loss of large myelinated fibers and the diameters of residual fibers shifted to small shown as size-frequency histogram. Many fibers are thinly myelinated and some of the Schwann cells looked as wrapping around the myelinate fibers with their processes. On gene analyses, we identified an Arg 1070 Stop homozygous mutation in the Periaxin, known to be a causative gene for CMT type 4F. Based on these observations, we emphasized that broad genetic analyses are necessary for diagnosis of CMT disease, including so far unidentified mutations among the Japanese populations.