[Distal hereditary motor neuropathy type II with mutation in heat shock protein 27 gene. A case report]

A 48-year-old man was admitted to our hospital with a tendency to stumble during walking. The family history indicated that the father was diagnosed with Charcot-Marie-Tooth disease (CMT) at the age of 55 and his younger sister (aunt) had similar symptoms that were considered to reflect autosomal dominant inheritance. Examination showed no pes cavus or inverted champagne-bottle thighs. In addition, the patient walked with foot drop due to weakness and atrophy of the distal parts of the lower extremities. Sensory examination revealed no deficits or abnormalities. Nerve conduction study and needle electromyography indicated pure motor axonal neuropathy. The diagnosis of distal hereditary motor neuropathy (distal HMN) type II was made. Genetic analysis detected mutation in the heat shock protein 27 (HSP27) gene. A recent report indicated that mutations in the HSP27 gene cause both distal hereditary motor neuropathy and CMT2F. In Japan, there are only a few reports of distal hereditary motor neuropathy with mutation in the HSP27 gene. Distal HMN should be considered in the differential diagnosis of patients with CMT like distal amyotrophy.