Charcot-Marie-Tooth Disease (CMT): Genetic Causes and Symptoms

Charcot-Marie-Tooth disease (CMT) is one of the most common inherited nerve disorders. It specifically targets the peripheral nerves, which act like electrical wires connecting your brain and spinal cord to your muscles and sensory organs.

The Biological Root: Nerve Communication

In a healthy body, peripheral nerves are insulated by a protective coating called myelin, or they rely on the nerve fiber (axon) to send signals. In CMT, genetic mutations cause these structures to break down.

Demyelinating CMT: The protective myelin sheath is damaged, slowing down the electrical signals.
Axonal CMT: The nerve fiber itself is damaged, reducing the strength of the signal reaching the muscles.

As these signals weaken, the muscles in the “extremities” (the hands and feet) begin to waste away because they aren’t receiving the necessary stimulation to stay strong.

Progressive Symptoms

CMT is a progressive condition, meaning it changes over time. While it is rarely life-threatening, it significantly impacts mobility.

Lower Extremities (Early Signs):
- Development of very high foot arches (pes cavus).
- Curled toes, known as hammertoes.
- A frequent tendency to trip or “foot drop” while walking.
Upper Extremities (Later Stages):
- Difficulty with fine motor skills (fastening buttons, writing).
- Loss of muscle bulk in the hands.
Sensory Issues:
- Numbness or tingling in the feet and hands.
- Reduced ability to feel temperature or pain in the affected areas.

Management and Support

While there is currently no cure for CMT, the goal of treatment is to maintain mobility and independence.

Treatment Type	Benefit
Physical Therapy	Strengthens muscles and prevents joint “freezing” (contractures).
Orthotics (AFOs)	Ankle-foot braces that help stabilize the gait and prevent tripping.
Occupational Therapy	Teaches new ways to perform daily tasks as hand strength changes.
Surgery	Can be used to correct severe foot deformities or stabilize joints.