Small heat shock protein 27 mutation in a Japanese patient with distal hereditary motor neuropathy.

Heat shock protein 27 (HSP27) belongs to a family of small heat shock proteins that play significant roles in the cellular stress response and are also involved in the control of protein-protein interactions as chaperons. Mutation in HSP27 has been identified as the cause of axonal Charcot-Marie-Tooth disease (CMT) and distal hereditary motor neuropathy (HMN). Heat shock protein 22 (HSP22) is a molecular counterpart of HSP27, and its mutation is another cause of distal HMN. We screened the mutation of HSP27 and HSP22 in 68 Japanese patients with axonal CMT or unclassified CMT and six Japanese patients with distal HMN. We detected a heterozygous P182S mutation of HSP27 in a patient with distal HMN, but we found no mutations in HSP22. Mutation in HSP27 may impair the formation of the stable neurofilament network that is indispensable for the maintenance of peripheral nerves.