Charcot-Marie-Tooth disease (CMT) is a neurological disorder, named after the three physicians who first described it in 1886 — Jean-Martin Charcot and Pierre Marie of France, and Howard Henry Tooth of the United Kingdom.
Unlike some neurological disorders, CMT isn’t life-threatening, and it almost never affects the brain. It causes damage to the peripheral nerves — tracts of nerve cell fibers that connect the brain and spinal cord to muscles and sensory organs.
Peripheral nerves control movement by relaying impulses from the spinal cord to muscles. They convey sensation by carrying feelings like pain and temperature from the hands and feet to the spinal cord. They also help control balance, by carrying information about the position of the body in space. They transmit information about the feet and hands to the spinal cord and then the brain, so that the brain knows where to place the feet when walking and where the hands should be placed to reach for something. Nerve damage, or neuropathy, causes muscle weakness and wasting, and some loss of sensation, in the extremities of the body: the feet, the lower legs, the hands and the forearms.
Although CMT can look very similar to acquired neuropathy — a type of nerve damage it caused by overexposure to certain chemicals, or disorders of the immune system — isn’t caused by anything a person does, and it isn’t contagious. It’s hereditary, meaning that it can be passed down through a family from one generation to the next.
CMT is sometimes called hereditary and motor sensory neuropathy (HMSN). Some doctors also use the old-fashioned name peroneal muscular atrophy, which refers to wasting of the peroneal muscle in the lower leg. There are even more names for CMT because the disease exists in many different forms, each unique in its severity, age of onset, progression and exact symptoms.
