Charcot-Marie-Tooth (CMT) disease is a group of genetic disorders that affects movement and sensation in the limbs. The disease progresses slowly and causes damage to the peripheral nerves that control muscles and transmit sensation.
CMT is caused by defects in specific genes (genetic mutations) often inherited in an autosomal dominant pattern. This means that for some forms of CMT, if one parent has CMT, each child has a 50% chance of inheriting the gene and the disease.
CMT can be classified in a number of ways:
Type I (demyelinating)—This type affects the coating of the nerve called the myelin sheath, causing nerve impulses to travel more slowly. It usually occurs in childhood or adolescence and is the most common type of CMT.
Type II (axonal)—This type affects the part of the nerve called axons. Although the speed is normal, the size or amount of impulses is less than normal. This type of CMT is less common and occurs after adolescence.
Type III—Also called Dejerine-Sottas disease, this is a more rare, severe, early onset form of CMT. It is sometimes considered to be a subtype of CMT Type I. Symptoms may include:
Delayed ability to walk due to weakness of the leg muscles closest to the trunk
Severe sensory problems
Type IV (demyelinating autosomal recessive)—This is similar to Type I, but often less severe.
The inheritance pattern also makes it less likely to be inherited by an affected individual's children.
The primary risk factor for developing CMT is having family members with this disease.
Symptom onset and type vary depending on the type of CMT. Usually, symptoms first appear in children and young adults. The first sign of CMT is often a high arched foot or difficulty walking. Other symptoms may include:
DNA blood test—to confirm certain types of CMT, even if there are no symptoms
Although there is no cure for CMT, treatment may help to improve function, coordination, and mobility. Treatment is also essential to protect against injury due to muscle weakness and diminished sensation. Treatment may include:
Physical and occupational therapy
Braces of lower legs
Shoe inserts to correct foot deformity
Foot care and routine exams with a specialist (podiatrist)
There are no known ways to prevent CMT once a person is born with the condition. If you have CMT or have risk factors, you may want to talk to a genetic counselor before deciding to have children.
Please be aware that this information is provided to supplement the care
provided by your physician. It is neither intended nor implied to be a
substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER
IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the
advice of your physician or other qualified health provider prior to
starting any new treatment or with any questions you may have regarding a