Charcot-Marie-Tooth, or CMT, is inherited peripheral neuropathy and is found worldwide among all races and ethnic groups. Discovered in 1886 by three physicians, Jean-Martin Charcot, Pierre Marie, and Howard Henry Tooth, CMT affects an estimated 2.6 million people.
CMT usually isn’t life-threatening and almost never affects brain function. It is not contagious, but it is hereditary and can be passed down from one generation to the next.
CMT patients slowly lose normal use of their extremities as nerves degenerate and muscles weaken because the affected nerves no longer stimulate the muscles. Many patients also have some loss of sensory nerve functions.
Although there are many different genetic causes of CMT, all types tend to have remarkably similar symptoms.
- A high arched foot is generally one of the first signs of this disorder, although in some instances extremely flat feet are also typical of CMT.
- As the disease progresses, structural foot deformities take place. The patient may develop a pes cavus (high-arched) foot and hammertoes.
- The progressive muscle wasting of CMT also leads to problems with walking, running, and balance. Ankle weakness and sprains are common, and many patients develop foot drop.
- Later in the course of the disease, hand function may become affected. Tasks requiring manual dexterity become difficult. The loss of nerve function is often accompanied by tingling and burning sensations in the hands and feet. This usually causes little more than mild discomfort, but some people experience severe neuropathic pain and require medication to control it.
- Weakness of the respiratory muscles is in rare in people with CMT, but when present, it can cause life-threatening problems. If shortness of breath is an issue, a patient should be checked by a respiratory specialist to see if the use of a ventilator is recommended.
It is important to note that the severity of symptoms can vary greatly from patient to patient, even within the same family. A child may or may not be more severely disabled than his/her parent. Some family members may experience significant impairment and require bracing while others have no noticeable symptoms but are found to have CMT upon examination by EMG or nerve conduction studies.