Charcot-Marie-Tooth disease type 4C in Japan: report of a case.

Introduction: The distribution of documented cases of Charcot-Marie-Tooth disease type 4C (CMT4C) is mainly limited to the Mediterranean region. We report the first documented case of CMT4C in East Asia. Furthermore, we estimate the proportion of CMT4C in Japan and compare the same with that in European countries.

Case Report: A 72-year-old Japanese woman presented with early-onset motor and sensory neuropathy associated with scoliosis, deformities of the hands and feet, and carpal tunnel syndrome. A genetic screen detected a homozygous p.R529Q mutation in SH3TC2, the causative gene of CMT4C. The SH3TC2 mutation identified here is unique among 426 unrelated Japanese CMT patients, excluding those with CMT1A.

Conclusions: Although CMT4C also occurs in Japan, it is less common than in European countries.