What Is Charcot-Marie-Tooth Disease? Alan Jackson Says He Has It

Find out more about the cause, symptoms, and treatments of this degenerative nerve disease.

Country singer Alan Jackson was diagnosed with Charcot-Marie-Tooth disease in 2011, according to TODAY. "I have this neuropathy and neurological disease," Jackson said. "It's genetic that I inherited from my daddy...There's no cure for it, but it's been affecting me for years.

Many people in the world are affected by Charcot-Marie-Tooth disease (CMT). This inherited neurological disorder affects over 2.6 million people worldwide—126,000 of which are in the US, according to the National Institute of Neurological Disorders and Stroke (NINDS). There are ways to manage CMT but there isn't a cure. Typically, the disease does not impact a person's life expectancy but it is common for a person with CMT to have some sort of physical disability.

"And it's getting more and more obvious. And I know I'm stumbling around on stage." Jackson said. "And now I'm having a little trouble balancing, even in front of the microphone, and so I just feel very uncomfortable."

If you want to know more about Charcot-Marie-Tooth disease—here's what you need to know.

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

Charcot-Marie-Tooth disease is a group of disorders (named for the three researchers who first described it in 1866) that cause damage to the peripheral nerves. According to the NINDS, the job of peripheral nerves is to send signals and information from the brain and spinal cord to the rest of the body.

People with the condition tend to develop progressive muscle weakness in their teens or early adulthood, but the disease can start at any age, according to the NINDS.

"CMT is a genetic disease, which means it will get worse over time," said Amit Sachdev, MD, medical director in the department of neurology at Michigan State University.

What Are the Symptoms of Charcot-Marie-Tooth Disease?

Because CMT affects the peripheral nerves, this includes sensory and motor nerves. These nerves trigger an impulse for muscle contraction which can lead to a variety of symptoms. According to the NINDS, the symptoms of CMT include:

  • Muscle weakness in your legs, ankles, and feet
  • Muscle cramps
  • Nerve pain
  • Tremor
  • Loss of muscle bulk (atrophy) in your arms, legs, hands, and feet
  • Difficulty lifting your foot (foot drop)
  • Frequent tripping or falling
  • Balance issues
  • Foot deformities (high foot arches and curled toes)
  • Reduced ability to feel heat, cold, or touch
  • Scoliosis (curvature of the spine)
  • Hip displacement
  • Problems with hearing and vision
  • Breathing difficulties

"CMT will cause both issues of sensation and strength," Dr. Sachdev said. Overall, there is a "broad range of severity" with CMT, said Paul Twydell, DO a neurologist at Spectrum Health. "Some people develop it in chidhood or adolescence. They typically have more weakness and need orthodics and equipment to help them walk," Dr. Twydell said. "Other people don't get diagosed until later in life—they tend to have a milder form of it."

What Causes Charcot-Marie-Tooth Disease?

Charcot-Marie-Tooth disease is an inherited, genetic condition. The mutations may damage the nerves or damage the myelin sheath, the protective coating that surrounds the nerve. This can cause weaker messages to travel between the limbs and the brain, according to the NINDS.

There are three different patterns of this gene mutation: autosomal dominant, autosomal recessive, and x-linked, according to the NINDS. The chances of inheriting CMT vary depending on what kind of gene mutation you have.

Autosomal Dominant

The autosomal dominant mutation means that only one parent with the CMT gene is needed to get the disease, according to the NINDS. So with this mutation, a child of an affected parent has a 50% chance of developing CMT.

Autosomal Recessive

The autosomal recessive mutation means that a person receives two mutated genes—one from each parent (the parents normally do not have CMT, just the gene for it), according to the NINDS. A child of the affected parents would have a 25% chance of inheriting the disease.

X-Linked

The x-linked mutation is when the mother has the mutation on one of her X chromosomes, according to the NINDS. The chances of inheriting the disease with an x-linked mutation vary depending on the sex of the child.

How Is Charcot-Marie-Tooth Disease Diagnosed?

There are quite a few ways that Charcot-Marie-Tooth disease can be diagnosed. According to NINDS, diagnosis can involve a few different tests, including:

Nerve Conduction Studies

During nerve conduction studies, electrodes are placed on the skin over a muscle or a nerve. These electrodes will create a small electrical impulse that stimulates the nerves. Information is then collected from this electrical activity.

Electromyography (EMG)

Electromyography (EMG) involves the insertion of a needle electrode through the skin to the muscle. This measures the bioelectrical activity of the muscles.

Physical Exam

A healthcare provider will perform a physical exam to look for any evidence of muscle weakness, atrophy, reduced tendon reflexes, sensory loss, or any other physical symptoms that may be present, according to the NINDS.

One specific sign of CMT is nerve enlargement, called hypertrophic nerves. This can be felt and/or seen through the skin and is caused by a thickened myelin sheath on the nerve.

"The most common thing we look for when diagnosing CMT is a high arch," said Clifford Segil, DO, a neurologist at Providence Saint John's Health Center in California. CMT also tends to affect the nerves on the outside of the foot, giving healthcare providers a good clue what may be behind a patient's symptoms. "It's fairly easy to diagnose," Dr. Segil said.

Genetic Testing

Given that CMT is an inherited condition, your healthcare proivder will also likely ask questions about your family history, Dr. Sachdev said. Genetic testing can also involve bloodwork.

Nerve Biopsy

Sometimes, healthcare providers may perform a nerve biopsy to confirm the diagnosis of CMT. Typically, a peripheral nerve sample will be taken from the calf and then analyzed under a microscope.

How Is Charcot-Marie-Tooth Disease Treated?

There is no cure for CMT, but patients may be treated with medication to help with nerve pain, according to the NINDS. It's also important to maintain mobility, flexibility, and muscle strength. "A healthy body will carry the nerves a long way," Dr. Sachdev explained.

Ankle braces and other orthopedic devices can help people with CMT get around more easily, Dr. Twydell said. Some people with the condition may also have orthopedic surgery to treat severe foot pain and joint deformities, according to the NINDS.

Summary

Charcot-Marie-Tooth disease is one of the most common inherited neurological disorders, according to the NINDS. This disease can affect your muscles, the way you walk, and can even cause some deformities. CMT doesn't typically affect someone's life expectancy. "It's not going to kill me. It's not deadly," Jackson said. Even though there isn't a cure, there are treatment options available that can improve the symptoms.

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