CHARCOT-MARIE-TOOTH DISEASE (CMT)

Symptoms

Early adulthood or youth is when symptoms frequently manifest. Typical signs include:

• Muscles in the foot, lower leg, hand, and forearm deteriorate and eventually waste away.
• The limbs, toes, and fingers losing their sense of touch

Other signs can include:

• High arches and hammertoes are the results of improper foot muscle development.
• Having trouble using the hands.
• Ankle instability and balance issues.
• Cramps in the forearms and lower thighs.
• Some hearing and visual impairment.
• Scoliosis
• Reduced reflexes

Even among close family members who have inherited the illness, symptoms and their intensity might differ greatly from person to person. Considering how minor the symptoms are in the early stages, many may not even be aware they have CMT.

Charcot-Marie-Tooth Disease Symptoms in Children

When symptoms first occur in a youngster, the child may:

• Be more accident-prone and clumsy than their classmates.
• They walk differently because it is difficult for them to get their feet off the ground with each stride.
• Have feet that rise and then descend forward.
• Other symptoms can manifest at any age, from very young to the late 70s, although they frequently start to manifest when the child reaches maturity and completes puberty.
• While the thighs maintain their typical muscular volume and structure, the contour of the leg may eventually alter, becoming extremely thin below the knee.

Over Time, Symptoms Often Intensify with:

• Growing hand and arm weakness made it harder to use the hands to do up buttons or open jar and bottle lids, for example
• Muscular and joint pain, since poor posture and gait put stress on the body, and neuropathic pain brought on by damaged nerves
• Issues with movement and walking, particularly in the elderly

Wheelchairs, leg braces, special shoes, and other orthopedic equipment are examples of assistive aids.

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

We are able to sense various sensations, such as pressure, temperature, touch, pain, and bodily position, thanks to sensory nerves. Muscles are directed to move and at what speed by motor neurons. Myelin is a type of insulation that nerves need in order to transmit powerful, quick messages across great distances. The nerve cannot function properly without adequate insulation. A person’s gene changes, or there is a mutation, causing CMT. A problem with a protein that the body needs for nerves to function normally can result from a variation in one of the CMT-related genes. Both sensory and motor nerves become incapable of transmitting information as a result of CMT mutations. Some CMT mutations impact the nerve cells, whereas others impact the myelin-coated nerve cells. Muscles grow progressively smaller and weaker without motor inputs. Children struggle to balance, walk, and handle little objects like buttons without sensory cues.

Diagnosed

Doctors will do an assessment, inquire about symptoms, and determine whether any family members have CMT or symptoms comparable to it. Tests can assist confirm that the issue is CMT rather than something that would improve with therapy. These tests consist of:

Genetic Testing for Charcot-Marie-Tooth Disease

This examines the kid’s DNA for recognized CMT mutations. Informing the patient and family about the type of mutation is helpful for doctors. To find out if they carry the mutation, family members might also be tested.

Nerve Conduction Velocity Testing and Electromyography

These test muscles and nerves to determine the source of weakness and determine whether peripheral neuropathy exists.

How CMT is Inherited

The genetic flaw that causes CMT can be inherited from either one or both parents in a child. No one defective gene alone causes CMT. Different genetic mutations lead to the various kinds of CMT, and there are numerous methods to pass on defective genes.

Autosomal Dominant

When one copy of a defective gene is sufficient to induce the disorder, autosomal dominant inheritance of CMT develops. There is a 50% probability that any kid each parent has will be born with the disorder if they both carry the defective gene.

Autosomal Recessive

When the faulty gene is present in two copies, autosomal recessive inheritance of CMT results. From each parent, you receive one copy. They don’t get CMT themselves because their parents only have one copy of the gene. If you and your partner are both autosomal recessive CMT gene carriers, there are the following possibilities:

• Each child will have has a 25% risk of developing CMT.
• Each child will have has a 50% chance of inheriting one of the faulty genes and passing the illness to any children they have — even if they won’t experience any CMT symptoms personally.
• There is a 25% chance that each child will inherit two healthy genes and not get CMT.

Children won’t get CMT if just 1 parent carries the autosomal recessive gene. However, there is a 50% probability that each child will have the gene.

X-linked Inheritance

The mutated gene is found on the X chromosome and is transferred from mother to son in X-linked inheritance. The components of cells called chromosomes are responsible for carrying your genes. Men have XY sex chromosomes. They get the X chromosome from their mother and the Y chromosome from their father. Women have XX chromosomes. They acquire one X chromosome from their mother and the other X chromosome from their father. Because the second healthy X chromosome balances the effect of the faulty one, a woman with the defective X chromosome often exhibits very moderate symptoms if any. However, there is a 50% possibility that she may carry the problematic gene to her son, who would then have CMT. CMT can skip a generation if a mother with the faulty X chromosome exclusively bears daughters until one of her grandsons acquires it.

Treatment of Charcot-Marie-Tooth Disease

Although CMT has no known therapy, it is possible to reduce symptoms and postpone the onset of physical impairments with treatment. NSAIDs, such as ibuprofen, can help lessen pain from injured nerves as well as discomfort in the muscles and joints. If NSAIDs fail to relieve your child’s symptoms, your doctor could recommend tricyclic antidepressants (TCAs). TCAs are often used to treat depression; however, they may also be effective for treating neuropathic pain. They could, however, have adverse consequences.

Stretching and strengthening activities with little impact are used in physical therapy. By doing so, you child may be able to keep their muscles strong for longer and avoid them from tightening. Occupational therapy can help people who have problems with finger movement or grip strength.  Assistive devices such as orthopedic aids, braces, and splints help individuals keep moving and prevent injury. High-ankle shoes or special boots provide additional ankle support, special shoes or insoles improve gait, and thumb splints can help with dexterity. Cognitive-behavioral therapy (CBT) helps people with CMT cope with everyday life and, if necessary, cope with depression.

In certain cases, surgery to remove a portion of a tendon or to fuse the bones in the foot can help with discomfort and facilitate walking. Surgery can treat heel abnormalities, ease joint discomfort, and treat flat feet. Patients who also suffer spinal curvature, or scoliosis, may require a back brace and perhaps surgery.

Outlook

CMT does not usually affect a person’s lifespan, but the outlook varies with the severity of the condition. For example, some people with CMT1 may have so mild symptoms that they do not realize they have the disease. Less than 5% of CMT1 patients need to use a wheelchair. There is no cure for CMT, but there are some steps as one gets older that they can take to prevent further problems.

These include:

• Avoiding caffeine and tobacco
• Limit alcohol consumption

As pediatric orthopedic doctors and specialists at the Medical City Children’s Orthopedics and Spine Specialists, with offices in Arlington, Dallas, Flower Mound,  Frisco, and McKinney, TX we treat Charcot-Marie-Tooth Disease (CMT).  If you believe your child has acquired this condition, please give us a call and make an appointment to begin a journey that will allow your child to lead the very best life possible.

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Footnote:

National Institute of Neurological Disorders & Stroke: Charcot Marie Tooth Disease