DISTAL HEREDITARY MOTOR NEUROPATHY TYPE-II (DISTAL HMN-II) - MAPPING OF A LOCUS TO CHROMOSOME 12Q24

The distal hereditary motor neuropathy (distal HMN) or the spinal form of Charcot-Marie-Tooth (CMT) disease is an exclusively motor disorder of the peripheral nervous system. The disorder clinically resembles t he hereditary motor and sensory neuropathies (HMSN) type I and type II or CMT type 1 and type 2, Distal HMN might also be related to the spi nal muscular atrophies (SMA) since, in both disorders, the lower motor neurons are affected. Electrophysiological and neuropathological exam inations of peripheral nerves show the absence of sensory involvement. We performed a genome search in an extended Belgian family with autos omal dominant distal HMN type II. Significant linkage was obtained wit h markers located at chromosome 12q24, and the gene for distal HMN II was assigned to the 13 cM interval between D12S86 and D12S340.