What Is Charcot-Marie-Tooth Disease (CMT)?

Charcot-Marie-Tooth disease (CMT) is not a tooth disease. It's a genetic (inherited) nerve disease that affects the nerve health and functioning in your extremities, including your feet, legs, hands, and arms.

These nerve-signaling problems between the brain and body parts affect your sensory nerves (nerves that signal cold and hot or soft and hard) and motor functioning skills. CMT is named after the three doctors who first described the disease in 1886.

This article will explore the symptoms and causes of CMT, how to get a diagnosis, what treatment options are available to someone with CMT, prognosis or what to expect if you have CMT, and expert tips for coping with this genetic nerve disease. 

Symptoms

Symptoms of Charcot-Marie-Tooth disease affect the legs and feet and hands and arms. They can include the following:

• Muscle weakness in lower legs and foot (can cause “foot drop,” difficulty lifting your foot while walking)
• Structural foot differences like high arch, flat feet, and hammertoe (a toe excessively bent at the middle joint)
• Loss of muscle around your hands, wrist, feet, and ankles
• Numbness, discomfort, and pain including joint and muscle pain in your hands and feet
• Loss of temperature sensation in hands and feet

Causes 

CMT is caused by genetic mutations, which can occur in a number of ways and for a variety of reasons. In some cases, people with CMT may have inherited the genetic mutations from their biological parents. In other cases, genetic mutations can occur spontaneously during conception and then are passed down to any future biological children.

There are over 40 different genes involved in CMT. Risk factors for inheriting and passing down genetic mutations associated with CMT are unique to each individual.

For example, in some cases only one copy of the genetic mutation from either biological parent is needed to inherit the disease. In these cases, a child with a biological parent with CMT has a 50% greater chance of inheriting the disorder.

Diagnosis

Diagnosis for CMT typically begins with a conversation between someone and their healthcare provider. It usually involves the following: 

• Medical history 
• Family history 
• Neurological examination 
• Physical examination (particularly of feet and legs and hands and arms) 

If you're experiencing symptoms or are feeling nervous, overwhelmed, or disorganized due to the stress of preparing for your medical appointment, you may want to consider bringing a friend or family member to take notes or bring up questions on your behalf.

Next, the healthcare provider may recommend detailed testing including:

• Nerve conduction studies or electromyography (EMG) to determine if symptoms are impacting nerves, muscles, or the connection between the two.
• Genetic testing with a blood test to help determine your likelihood of symptoms being from CMT
• Nerve biopsy (testing a sample of the nerve) from your leg area in rare cases in which other tests were inconclusive

Complications

Complications of nerve problems can occur. These include injuries from slipping or falling due to muscle weakness in legs and feet or infections in the feet that can go untreated due to a lack of typical pain sensation signaling or temperature sensations. Seeking medical treatment can help prevent complications. 

Treatment 

There is no treatment that can cure CMT, however, there are ways to reduce symptoms impacting your quality of life. Options for CMT treatment include:

• Physical therapy to help stretch nerves and strengthen muscles to help slow weakness, numbness
• Occupational therapy to support you in exercising motor skills and adapting to daily tasks  
• Orthopedic devices, including wearing ankle braces, splints, or high-top boots for more ankle support
• Medications for reducing sensations of pain, if needed

Coping

Coping with any kind of nerve issue that causes pain and limits your mobility is challenging not only physically, but mentally, too. Coping with CMT can include reaching out for peer and mental health support. You may want to start by visiting the Charcot-Marie-Tooth Association (CMTA) from the  National Organization for Rare Diseases (NORD). 

Struggling to accept a recent diagnosis is understandable and normal. Talking with a trained mental health professional may be helpful. 

Summary

Charcot-Marie-Tooth Disease is a genetic condition that affects the nerves. Symptoms include weakness, pain, and sensory issues leading to challenges with motor skill functioning. While there is no cure, there are treatments that can help support a healthy life with CMT.

These include physical therapy to build strength and slow disability, occupational therapy and devices to help with mobility, and medications to reduce symptoms of pain. If interested, support groups and therapy may also help you cope with Charcot-Marie-Tooth disease.