Charcot Marie Tooth Syndrome

Charcot–Marie-Tooth syndrome is one of the most common inherited disorders of the peripheral nervous system affecting about 1 in 2,500 people and is presently incurable. It mainly affects the hands and feet, progressively deteriorating with age, but is normally not life threatening. It has a number of alternative names including Hereditary Motor and Sensory Neuropathy (HMSN), or Peroneal Muscular Atrophy, but is usually referred to as CMT.

CMT is a genetic condition, passed from parent to child. It has a 50 / 50 chance of being inherited, and has no preference to either race or gender. If there is a family history of this condition, then there are genetic and electromyography examinations that can confirm a diagnosis. It is also possible for the gene to mutate causing CMT. This means CMT can still be present even if there is no history of it before. The mechanisms for this are unknown beyond the normal gene mutation that occurs during reproduction.

Although CMT is a condition of the nervous system, the results affect the muscles in the extremities of the limbs. The ‘movement’ messages from the brain travel down the spine, and then out through the nerves to the muscles. Normally, the motor signals travel efficiently and uninterrupted, however, with CMT there is a deficiency in protective nerve ending chemicals (axon or the myelin) which inhibits the signals. Muscles do not get the ‘movement’ signals and therefore begin to waste. Pain and temperature senses are normally unaffected, as these are sent via different nerves.

The first symptoms of this condition can usually be seen by the age of 10 years. As the muscles in the foot and ankle weaken, the child will develop a condition called ‘foot drop’. This is quite literally the dropping of the feet when walking, the mussels not being able to hold the foot up as the leg moves. This can cause difficulty in walking and running, and may result in frequent trips and falls. To compensate, it is natural to develop a high-stepped gait, which requires a lot more physical effort.

A high arched foot, with hammertoes, can be another early sign. The arching, with the drop foot, can result in pressure sores on the front of the feet and the heel, as the middle of the foot has very little pressure exerted on it. It should be remembered that the normal method of walking - placing the heel down first, toes lifting last – can not be achieved with CMT, rather the toes are placed first, then heel, with the toes lifting last again. Shoe splints can be a great aid with this. These splints are placed in the shoe (and usually fastened around the lower leg) and hold the ankle at 90 degrees. This helps prevent falls and improves the walking gate.

Later in life, the hands can also be affected. As with the feet, there may be signs of muscle weakness or wasting. The fingers are particularly vulnerable to this; in some cases they can develop a curled appearance and the inability to straighten them without help. However, it is unlikely that such forced straightening will be painful or difficult. This disability may cause problems if a job involves intricate finger work – there may not be the fine mobility in the hands.

Despite the problems that can be encountered, it should be remembered that you could lead a normal life with CMT. Except in unusual cases, it does not inflict long-term chronic pain, and does not normally result in extreme disability. With a healthy life style, plenty of exercise and a good diet, its impact on day-to-day life can be minimised. However, as mentioned above, there is no known cure, and it will gradually get worse throughout life.

As with any medical condition, you should seek proper medical advice. The information here is just general information about CMT and should not be taken as medical advice.

If you wish to find out more about CMT you should consult your doctor. Or if you wish to contact a support group, the following sites may helpful.