Charcot-Marie-Tooth disease

Charcot (shahr-KOH)-Marie-Tooth disease is a group of inherited disorders that cause nerve damage. This damage is mostly in the arms and legs (peripheral nerves). Charcot-Marie-Tooth disease is also called hereditary motor and sensory neuropathy.

Charcot-Marie-Tooth disease results in smaller, weaker muscles. You may also experience loss of sensation and muscle contractions, and difficulty walking. Foot deformities such as hammertoes and high arches also are common. Symptoms usually begin in the feet and legs, but they may eventually affect your hands and arms.

Symptoms of Charcot-Marie-Tooth disease typically appear in adolescence or early adulthood, but may also develop in midlife.

Signs and symptoms of Charcot-Marie-Tooth disease may include:

• Weakness in your legs, ankles and feet
• Loss of muscle bulk in your legs and feet
• High foot arches
• Curled toes (hammertoes)
• Decreased ability to run
• Difficulty lifting your foot at the ankle (footdrop)
• Awkward or higher than normal step (gait)
• Frequent tripping or falling
• Decreased sensation or a loss of feeling in your legs and feet

As Charcot-Marie-Tooth disease progresses, symptoms may spread from the feet and legs to the hands and arms. The severity of symptoms can vary greatly from person to person, even among family members.

Charcot-Marie-Tooth disease is an inherited, genetic condition. It occurs when there are mutations in the genes that affect the nerves in your feet, legs, hands and arms.

Sometimes, these mutations damage the nerves. Other mutations damage the protective coating that surrounds the nerve (myelin sheath). Both cause weaker messages to travel between your limbs and brain.

Charcot-Marie-Tooth disease is hereditary, so you're at higher risk of developing the disorder if anyone in your immediate family has the disease.

Other causes of neuropathies, such as diabetes, may cause symptoms similar to Charcot-Marie-Tooth disease. These other conditions can also cause the symptoms of Charcot-Marie-Tooth disease to become worse. Medications such as the chemotherapy drugs vincristine (Marqibo), paclitaxel (Abraxane) and others can make symptoms worse. Be sure to let your doctor know about all of the medications you're taking.

Complications of Charcot-Marie-Tooth disease vary in severity from person to person. Foot abnormalities and difficulty walking are usually the most serious problems. Muscles may get weaker, and you may injure areas of the body that experience decreased sensation.

Sometimes the muscles in your feet may not receive your brain's signal to contract, so you're more likely to trip and fall. And your brain may not receive pain messages from your feet, so if you've rubbed a blister on your toe, for example, it may get infected without your realizing it.

You may also experience difficulty breathing, swallowing or speaking if the muscles that control these functions are affected by Charcot-Marie-Tooth disease.

During the physical exam, your doctor may check for:

• Signs of muscle weakness in your arms, legs, hands and feet
• Decreased muscle bulk in your lower legs, resulting in an inverted champagne bottle appearance
• Reduced reflexes
• Sensory loss in your feet and hands
• Foot deformities, such as high arches or hammertoes
• Other orthopedic problems, such as mild scoliosis or hip dysplasia

Your doctor may also recommend the following tests, which can help provide information about the extent of your nerve damage and what may be causing it.

• Nerve conduction studies. These tests measure the strength and speed of electrical signals transmitted through your nerves. Electrodes on the skin deliver small electric shocks to stimulate the nerve. Delayed or weak responses may indicate a nerve disorder such as Charcot-Marie-Tooth disease.
• Electromyography (EMG). A thin needle electrode is inserted through your skin into the muscle. Electrical activity is measured as you relax and as you gently tighten the muscle. Your doctor may be able to determine the distribution of the disease by testing different muscles.
• Nerve biopsy. A small piece of peripheral nerve is taken from your calf through an incision in your skin. Laboratory analysis of the nerve distinguishes Charcot-Marie-Tooth disease from other nerve disorders.
• Genetic testing. These tests, which can detect the most common genetic defects known to cause Charcot-Marie-Tooth disease, are done with a blood sample. Genetic testing may give people with the disorder more information for family planning. It can also rule out other neuropathies. Recent advances in genetic testing have made it more affordable and comprehensive. Your doctor may refer you to a genetic counselor before testing so you can best understand the pros and cons of testing.

There's no cure for Charcot-Marie-Tooth disease. But the disease generally progresses slowly, and it doesn't affect expected life span.

There are some treatments to help you manage Charcot-Marie-Tooth disease.

Medications

Charcot-Marie-Tooth disease may sometimes cause pain due to muscle cramps or nerve damage. If pain is an issue for you, prescription pain medication may help control your pain.

Therapy

• Physical therapy. Physical therapy can help strengthen and stretch your muscles to prevent muscle tightening and loss. A program usually includes low-impact exercises and stretching techniques guided by a trained physical therapist and approved by your doctor. Started early and followed regularly, physical therapy can help prevent disability.
• Occupational therapy. Weakness in the arms and hands can cause difficulty with gripping and finger movements, such as fastening buttons or writing. Occupational therapy can help through the use of assistive devices, such as special rubber grips on doorknobs, or clothing with snaps instead of buttons.

• Orthopedic devices. Many people with Charcot-Marie-Tooth disease require the help of certain orthopedic devices to maintain everyday mobility and to prevent injury. Leg and ankle braces or splints can provide stability while walking and climbing stairs.

  Consider boots or high-top shoes for additional ankle support. Custom-made shoes or shoe inserts may improve your gait. Consider thumb splints if you have hand weakness and difficulty with gripping and holding things.

Surgery

If foot deformities are severe, corrective foot surgery may help alleviate pain and improve your ability to walk. Surgery can't improve weakness or loss of sensation.

Potential future treatments

Researchers are investigating a number of potential therapies that may one day treat Charcot-Marie-Tooth disease. Potential therapies include medications, gene therapy and in vitro procedures that may help prevent passing the disease to future generations.

Some habits may prevent complications caused by Charcot-Marie-Tooth disease and help you manage its effects.

Started early and followed regularly, at-home activities can provide protection and relief:

• Stretch regularly. Stretching can help improve or maintain the range of motion of your joints and reduce the risk of injury. It's also helpful in improving your flexibility, balance and coordination. If you have Charcot-Marie-Tooth disease, regular stretching can prevent or reduce joint deformities that may result from uneven pulling of muscle on your bones.
• Exercise daily. Regular exercise keeps your bones and muscles strong. Low-impact exercises, such as biking and swimming, are less stressful on fragile muscles and joints. By strengthening your muscles and bones, you can improve your balance and coordination, reducing your risk of falls.
• Improve your stability. Muscle weakness associated with Charcot-Marie-Tooth disease may cause you to be unsteady on your feet, resulting in falls and serious injury. Walking with a cane or a walker can increase your stability. Good lighting at night can help you avoid stumbling and falling.

Foot care is important

Because of foot deformities and loss of sensation, regular foot care is important to help relieve symptoms and to prevent complications:

• Inspect your feet. Check them daily to prevent calluses, ulcers, wounds and infections.
• Take care of your nails. Cut your nails regularly. To avoid ingrown toenails and infections, cut straight across and avoid cutting into the nailbed edges. A podiatrist can trim toenails for you if you have problems with circulation, sensation and damage to the nerves in your feet. Your podiatrist may also be able to recommend a salon to safely trim your toenails.
• Wear the right shoes. Choose properly fitting, protective shoes. Consider wearing boots or high-top shoes for ankle support. If you have foot deformities, such as a hammertoe, explore having shoes custom made.

Support groups, in conjunction with your doctor's advice, can be valuable in dealing with Charcot-Marie-Tooth disease. Support groups bring together people who are coping with the same kinds of challenges, and offer a setting in which people can share common problems.

Ask your doctor about support groups in your community. The internet and your local health department, public library and telephone book also may be good sources to find a support group in your area.

You might first discuss your symptoms with your family doctor, but he or she will probably refer you to a neurologist for further evaluation.

Because there's much to discuss in a short time, try to arrive well prepared. Here's some information to help you get ready for your appointment and know what to expect from your doctor.

What you can do

• Be aware of any pre-appointment restrictions. At the time you make the appointment, be sure to ask if there's anything you need to do in advance, such as restrict your diet.
• Write down any symptoms you're experiencing, including any that may seem unrelated to the reason for which you scheduled the appointment.
• Make a list of all medications, vitamins or supplements that you're taking.
• Ask a family member or friend to come with you, if possible. Sometimes it can be difficult to remember all of the information provided to you during an appointment. Someone who accompanies you may remember something that you missed or forgot.
• Write down questions to ask your doctor.
• Ask relatives if they know of any other family members with similar symptoms.

Your time with your doctor may be limited, so try to prepare a list of questions. For Charcot-Marie-Tooth disease, some basic questions to ask your doctor include:

• What's the most likely cause of my symptoms?
• What kinds of tests do I need? Do these tests require any special preparation?
• Will this condition go away, or will I always have it?
• What treatments are available, and which do you recommend for me?
• What are the possible side effects for treatment?
• I have other health conditions. How can I best manage these conditions together?
• Do I need to follow any activity restrictions?
• Are there any brochures or other printed material that I can take home with me? What websites do you recommend visiting?

What to expect from your doctor

Your doctor is likely to ask you a number of questions. Being ready to answer them may reserve time to go over any points you want to spend more time on. Your doctor may ask:

• When did you begin experiencing symptoms?
• How severe are your symptoms?
• Do you have symptoms all the time, or do they come and go?
• Does anything seem to make your symptoms better?
• Does anything make your symptoms worse?
• Does anyone in your family have similar symptoms?
• Have you or others in your family had genetic testing to confirm the diagnosis?