Charcot-Marie-Tooth Disease (CMT)

Charcot-Marie-Tooth (CMT) disease causes worsening weakness in your feet and hands due to peripheral nerve damage. It can also cause sensory-related symptoms, like numbness.

Muscle weakness usually starts in your feet and lower legs. Over time, it can affect your fingers, hands and arms, too. Most people begin to get symptoms in their teen years or early adulthood. But symptoms can start at any age.

CMT disease is the most common inherited (genetic) neuromuscular disorder. But it’s rare overall. It affects about 1 in 2,500 people. The condition is named after the three doctors who first described it.

The symptoms can feel subtle at first. You might notice a bit more clumsiness or feel like your ankles aren’t quite supporting you. If something feels off, reach out to your healthcare provider.

Symptoms of Charcot-Marie-Tooth disease

CMT disease can cause motor (muscle-related) and/or sensory symptoms. Common symptoms include:

• Foot issues, like high arches, hammertoes or flat feet
• Muscle weakness and loss
• Difficulty with balance and coordination
• Tripping or frequent falls
• Twisting or spraining your ankles frequently
• Foot drop
• Difficulty walking or running
• Delayed motor milestones in young children
• Paralysis
• Numbness or tingling
• Creeping sensations in your legs
• Inability to feel heat or pain sensations in your lower legs, feet and hands
• Chronic pain
• Decrease in vision or hearing senses

These symptoms can range from very mild to severe. Having other conditions that can cause peripheral nerve damage, like diabetes, can make CMT symptoms worse.

Charcot-Marie-Tooth disease causes

Gene changes cause CMT. It can be a change in just one gene or several. Over 100 gene changes are linked to the condition. So, there are many types of it. You inherit the gene change(s) from your biological parent(s). Types of inheritance patterns include:

• Autosomal recessive: Both parents need to have the altered gene to pass it on.
• Autosomal dominant: Only one parent needs to have the altered gene to pass it on.
• X-linked: The altered gene is on the X chromosome. Males typically have more severe symptoms because they only have one X chromosome.

With CMT, the gene changes affect the cells (neurons) in your peripheral nerves in one of two ways (or both):

• Myelin loss: The myelin sheath is a protective cover that wraps around part of a nerve cell. CMT can result in too little or a total lack of myelin. This slows down the speed of signals traveling through your neurons. In these cases, CMT is a demyelinating disease.
• Axon damage: The axon is the part of a neuron that converts electrical signals into chemical signals. CMT can cause the axons to shrink or waste away. This weakens the signals that come and go.

Types of this condition

The Charcot-Marie-Tooth Association has recorded over 160 subtypes of CMT disease. Most cases fall into four groups.

Complications of this condition

Foot deformities are the main complication of CMT. They tend to get worse over time and can eventually make it impossible to walk without help. Corns, calluses and ulcers can form on your feet, as well.

If you have a loss of sensation in your feet, ulcers and injuries can lead to infection. This is because you may not realize you have them with no feeling of pain.

How doctors diagnose Charcot-Marie-Tooth disease

Your healthcare provider will ask about your medical history and family history. They’ll do physical and neurological exams. You’ll likely need to see a neurologist for further testing.

It may take a combination of tests to get an accurate diagnosis and know the specific type of CMT you have. Tests may include:

• Electromyogram and nerve conduction velocity (NCV) tests
• Genetic testing
• MRI and/or ultrasound
• Nerve biopsy

How is it treated?

There’s no way to cure CMT or treat the condition directly. But therapies and medicines can help manage your symptoms.

Common treatments for CMT include:

• Physical and occupational therapy
• Leg braces, walkers, wheelchairs and other mobility support devices
• Special footwear for changes in foot shape
• Surgery to correct changes in the shape of your hands, feet, hips or back
• Medications for some symptoms, especially chronic pain

Your healthcare provider will suggest various therapies as needed. They’re experts in finding which treatments are most likely to help you based on your specific case.

When should I see my healthcare provider?

You’ll have regular follow-up visits with your healthcare provider to check on your symptoms. Reach out to them if you notice any changes, especially ones that disrupt your usual activities or routine.

If you have a fall, get emergency care if there’s any risk of injury to your head, neck or back.

It may be helpful to ask your provider the following questions:

• How can I tell if CMT is getting worse?
• Are there any clinical trials I should consider?
• Are there new adaptive devices or technologies that could help?
• What kind of exercise is safe and beneficial for me?
• How likely am I to lose the ability to walk?
• If I want to have biological children, what are the chances of passing CMT on?

What can I expect if I have this condition?

Charcot-Marie-Tooth disease affects each person differently. Most people with CMT develop problems with movement or sensations. But these rarely affect how long you live. With the help of special devices and other kinds of care, it’s possible to do many of the things you love.

Having a condition that gets worse over time can take a toll on your mental health. Reach out to a mental health professional if it’s causing distress.