Charcot-Marie-Tooth disease | Hereditary disorder

DEFINITION

Charcot (shahr-KOH)-Marie-Tooth disease is a group of hereditary disorders that damage the nerves in your arms and legs (peripheral nerves). Charcot-Marie-Tooth is also known as hereditary motor and sensory neuropathy.

The main signs and symptoms of Charcot-Marie-Tooth disease are muscle weakness and decreased muscle size. You may also notice decreased sensation in affected areas. Foot deformities such as hammertoes and high arches are common in Charcot-Marie-Tooth disease. Symptoms usually begin in your feet and legs, but they may eventually affect your hands and arms. 

Muscle weakness and loss of balance can make walking difficult. Symptoms of Charcot-Marie-Tooth disease typically appear in adolescence or early adulthood, but this condition can develop in midlife too.

SYMPTOMS

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

• Weakness in your legs, ankles and feet 
• Loss of muscle bulk in 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 not be limited to the feet and legs but may also involve the hands and arms. The severity of symptoms can vary greatly from person to person. This is true even among family members.

CAUSES

Charcot-Marie-Tooth disease is a group of related conditions all caused by inherited mutations in genes involved with the structure and function of the nerves that serve your feet, legs, hands and arms.

In some cases, these genetic mutations result in damage to the nerve itself. Other mutations damage the myelin sheath, the protective coating that surrounds the nerve. The end result, however, is the same — weaker messages traveling between your extremities and your brain.

That means some of 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.

RISK FACTORS

Charcot-Marie-Tooth disease is hereditary, so you're at higher risk of developing the disorder if anyone in your immediate family has had the disease. Other causes of neuropathies, such as diabetes, may cause symptoms of or worsen Charcot-Marie-Tooth disease.

COMPLICATIONS

Complications of Charcot-Marie-Tooth disease vary in severity from person to person, with foot abnormalities and difficulty walking generally being the most serious problems. Muscle weakness may also increase, and injury to areas of the body with decreased sensation may occur.

PREPARING FOR YOUR APPOINTMENT

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 appointments can be brief, and because there's often a lot of ground to cover, it's a good idea 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. 

Your time with your doctor may be limited, so preparing a list of questions can help you make the most of your time together. 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? 

TESTS AND DIAGNOSIS

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 are placed on your skin and deliver small electric shocks that 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 to be tested. 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 the calf of your leg 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 by blood sample. Genetic testing may give people with the disorder more information for family planning. It's important to have genetic counseling before undergoing genetic testing so you know the pros and cons of testing.

TREATMENTS AND DRUGS

There's no cure for Charcot-Marie-Tooth disease. But, the disease generally progresses slowly, and the expected length of life isn't shortened by the disorder.

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

Medications

Some, but not all people with the disease may experience 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 physical therapy program usually consists of 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 play an important part in delaying nerve deterioration and muscle weakness before disability occurs. 
• Occupational therapy. Some people with Charcot-Marie-Tooth disease may experience weakness in their arms and hands, causing difficulty with gripping and finger movement. Normal daily activities, such as fastening buttons or writing, can become difficult. Occupational therapy can help you deal with such challenges 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 during walking and climbing stairs. 

  Wearing boots or high-top shoes may provide additional ankle support. Custom-made shoes or shoe inserts may improve your gait. If you have hand weakness and difficulty with gripping and holding things, thumb splints may help.

Surgery

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

Future treatments

Researchers are investigating a number of potential therapies that may one day treat Charcot-Marie-Tooth disease. Gene therapy might be able to fix the genetic defect that causes the disease, while other treatments are focusing on correcting the damage done by the defective genes. These potential therapies are all in the earliest stages, and aren't yet being studied in humans. However, the may offer hope for the future.

LIFESTYLE AND HOME REMEDIES

Certain tactics may prevent complications caused by Charcot-Marie-Tooth disease and improve your ability to manage the effects of the disorder.

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

• Stretch regularly. The goal of stretching is to improve or maintain the range of motion of your joints. Stretching improves your flexibility, balance and coordination. Stretching may also reduce your risk of injury. 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. Exercising every day 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, which can lead to falling 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. Daily inspection of your feet is important 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. If you have trouble with this task, consider having your nails trimmed by a foot doctor (podiatrist). 
• Wear the right shoes. Use shoes that fit properly and are protective. Consider wearing boots or high-top shoes for ankle support. If you have foot deformities, such as a hammertoe, you may need to consider having shoes custom made.