A Family with Distal Hereditary Motor Neuropathy and a K141Q Mutation of Small Heat Shock Protein HSPB1

We herein describe a Japanese family with distal hereditary motor neuropathy carrying a K141Q mutation of small heat shock protein HSPB1. Two patients among them had late onset disease (older than 50 years). The muscles of the distal legs were weak and atrophic. Sensory and autonomic dysfunction were not seen. Even eight years after onset, one patient could still walk without support. A nerve conduction study revealed axonal degeneration of the motor nerves of the legs. A heterozygous K141Q mutation was detected in the affected patients. The late onset and mild clinical phenotype might reflect the mild biochemical alteration of HSP27 induced by the K141Q mutation.