A disease of the peripheral nerves that control muscles, unlike the muscular dystrophies, which affect the muscles themselves.

Before the molecular biology and genetic testing era, CMT disorders were broadly classified into Type 1 (with abnormally low nerve conduction velocities, suggesting demyelination) and Type 2 (with normal nerve conduction velocities, suggesting axonal or neuronal degeneration). Found in both genders and in all races and ethnic groups, it is the most commonly inherited peripheral neuropathy, affecting 2.8 million people worldwide. This rare, inherited, slowly progressive neuropathies that came to be known as Charcot-Marie-Tooth (CMT) disorders were described independently in 1886 by Charcot and Marie in France and by Tooth in the UK. Onset can occur at any age but is most frequent in childhood or adolescence.