Charcot-Marie-Tooth disease (CMT) is an inherited neurological disorder. It affects
the peripheral nerves (nerves outside the brain and spinal cord), causing muscle weakness
CMT happens because of problems with motor nerves (which control muscles) and sensory
nerves (which send sensations to the brain).
What Are the Signs & Symptoms of Charcot-Marie-Tooth Disease?
There are many different types of CMT. Symptoms and the age when they begin depend
on the type. In some types of CMT, babies and toddlers have weakness and muscle loss.
hold their head up, sit, crawl, stand, and walk later than most kids do
fall more than brothers, sisters, or playmates of the same age
have trouble grasping or holding items
In the most common forms of Charcot (shahr-KOE)-Marie-Tooth disease, symptoms first
appear in teenagers or young adults. Symptoms all relate to muscle weakness or numbness
in the hands, forearms, lower legs, and feet, and include:
cold hands and feet
trouble buttoning clothing and holding small items such as coins
stumbling or unsteady steps, which may look like clumsiness
dragging the feet or toes while walking (foot drop)
trouble going up or down steps
shuffling or marching steps
feet with high arches and toes that stay curled (hammertoes)
loss of feeling in the feet or legs
trouble with balance
What Causes Charcot-Marie-Tooth Disease?
Sensory nerves let us feel pain, pressure, touch, temperature, body position, and
other feelings. Motor nerves tell muscles to move and how fast. To send strong and
fast signals over long distances, nerves have to be wrapped in insulation called myelin.
If the insulation doesn't work well, the nerve can't either.
CMT happens because of a mutation or variation (a change) in a person's gene
(DNA). A variation in one of the CMT-related genes can cause a problem with a protein
that the body needs for nerves to work properly.
CMT mutations cause both sensory nerves and motor nerves to lose their ability
to send signals. Some CMT mutations affect the nerve cells and others affect the cells
that wrap the nerve in myelin. Without motor signals, muscles get smaller and weaker.
Without sensory signals, children have trouble balancing, walking, and handling small
items like buttons.
Who Gets Charcot-Marie-Tooth Disease?
Many genes can cause CMT if they don't work properly. The type of CMT depends on
what gene is affected.
Sometimes, the parents' DNA is normal and the CMT variation happens when the child's
DNA is forming. This is called a new or spontaneous mutation.
How Is Charcot-Marie-Tooth Disease Diagnosed?
Doctors will do an exam, ask about symptoms, and find out whether family members
have CMT or similar symptoms.
Tests can help make sure the problem is CMT and not something that could go away
with treatment. These tests include:
This checks the child's DNA for known CMT mutations. Knowing the kind of
mutation helps doctors tell the patient and family what to expect. Family members
also can be tested to see if they have the mutation.
Nerve conduction velocity (NCV) testing and electromyography
(EMG): These check nerves and muscles to find the cause of weakness and see
if there is peripheral
How Is Charcot-Marie-Tooth Disease Treated?
There is no cure for CMT disease yet. The treatment goal is to help the child stay
as active as possible. Because of the loss of feeling, avoiding injury from impact
and burns requires
Treatments to help children stay as active as possible include:
Braces, such as ankle-foot orthoses (AFOs), to support the feet for easier walking.
Surgery to loosen tight tendons and joints (contractures).
Doctors will also check for other problems that are rare in CMT disease, like trouble
with breathing during sleep.
Often, CMT symptoms are not severe, and many treatments can help. People with CMT
have a normal life expectancy, and most can walk their entire lives. Support
groups can help you and your child — they can connect you to other families who
are managing CMT and keep you up to date on treatment research.