The shifting paradigm of Charcot-Marie-Tooth disease.

Molecular studies have created a paradigm shift in our perception of Charcot-Marie-Tooth disease (CMT). Indeed, CMT has evolved from the concept of a rather homogeneous hereditary disease exclusively involving peripheral nerves to the concept of a highly heterogeneous clinical and genetic syndrome mainly - but sometimes not exclusively - involving the peripheral nervous system. The phenotypic spectrum of CMT overlaps with other inherited neuropathies such as distal hereditary motor neuropathy (dHMN), hereditary sensory and autonomic neuropathy (HSAN), spinal muscular atrophy (SMA) subtypes, and the neuropathies of mitochondrial disorders. At a molecular level, mutations in one given gene may alternatively provoke CMT, HSAN, dHMN or SMA variants. Over the last years, there have been dramatic advances in deciphering the molecular basis for many CMT subtypes and more than 900 different mutations in more than 60 causative genes are now described. However, as 75% of CMT causative genes apparently remain unknown and as disease-specific therapies are not available, major advances are yet to come in the field of CMT.