Definition

Charcot-Marie-Tooth (CMT) disease is a group of inherited disorders. It affects movement and feeling in the arms and legs. The disease progresses slowly and causes harm to the nerves that control muscles and transmit sensation.

CMT can be:

  • Type 1—This type affects the coating of the nerve called the myelin sheath, causing nerve impulses to travel more slowly. It usually happens to children and teens. It is the most common type of CMT.
  • Type 2—This type affects the part of the nerve called the axons. The speed of the nerves is normal, but the size or amount of impulses is less than normal. This type of CMT is less common. It happens after the teen years.
  • Type 3—Also called Dejerine-Sottas disease, this is a rare, severe form of CMT. It is sometimes thought to be a subtype of CMT Type 1.
  • Type 4—This is like Type 1, but often less severe. If you have it, you are less likely to pass it on to your children.

Causes

CMT is caused by changes in genes. In most people, the change is inherited. Some forms happen when only one copy of the abnormal gene is inherited while other forms happen when both copies are inherited. Some other forms are inherited due to an abnormal x-linked chromosome.

Nerve Cell

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Risk Factors

Your risk is higher if you have family members with this disease.

Symptoms

Your symptoms depend on the type of CMT you have. Symptoms often start before age 30. The first sign is often a high arched foot or problems walking.

You may also have:

  • Flexed toes
  • A hard time holding the foot up in a horizontal position
  • Slapping the feet on the floor when walking
  • Muscle cramping, weakness, and wasting in the legs—can spread to the arms later in life
  • Decreased feeling in the feet and legs
  • Problems with balance
  • Type 3 symptoms:
    • Babies who learn to walk late due to weakness of the leg muscles closest to the trunk
    • Severe sensory problems
    • Hearing loss

Diagnosis

You may be asked about your symptoms and health history. A physical exam will be done.

You may have nerve and muscle functions tested. This can be done with:

Your doctor may need to test your DNA. This can be done with a blood test.

Treatment

There is no cure. Treatment may help to reduce symptoms. You may need:

You may need:

  • Physical and occupational therapy
  • Braces on the lower legs
  • Shoe inserts to correct foot deformity
  • Foot care and routine exams with a foot specialist
  • Surgery

Prevention

There are no known ways to prevent CMT. If you or a family member have CMT or have risk factors, you may want to talk to a genetic counselor to understand the risk of passing on the disease before deciding to have children.