[Progress of clinical and genetic research on distal hereditary motor neuropathy]

Distal hereditary motor neuropathy (dHMN) is a group of clinically and genetically heterogeneous disorders characterized by progressive distal weakness and atrophy. The onset of dHMN is at mid-adulthood or early childhood, and the symptoms are mainly present in the lower limbs. Besides weakness and atrophy of distal limb muscles, some patients may develop bulbar paralysis, and some may also present with mild sensory disturbance. Decreased or absent tendon reflexes may be discovered. Electromyography may show neurogenic damages. Muscular biopsy may reveal neurogenic amyotrophy. An increasing number of genes have been associated with dHMN. Pathogenesis of dHMN may include formation of protein aggregates, impairment of autophagy pathway, RNA processing, translation synthesis, axonal transport, endoplasmic reticulum stress, calcium channel and neuroprotection. A review for recent progress made on clinical characterization and molecular genetics of dHMN is provided.