Charcot-Marie-Tooth disease, named for the two French scientists and the English doctor who separately discovered it in 1886, is a genetic disease that affects about one in 2,500 people, making it the most common genetically based nervous system disorder. It is caused by genetic mutations that affect the myelin sheath that protects the nerves, disrupting the signals from the brain. It leads to muscle weakness, foot problems, pain or loss of sensation in the extremities, poor muscle development and muscle loss, frequent falls, and an odd gait. Symptoms usually start in early childhood, though in some cases initial onset may not strike until after age 30. Charcot-Marie-Tooth is a hereditary condition, afflicting anyone born with the genetic mutations that cause the symptoms.
As the disease progresses, the patient may slowly lose manual dexterity and suffer increasing weakness in the hands and arms. In some people, hearing and eyesight get progressively worse over time. Many patients develop the spinal deformation known as scoliosis, in which the spine starts to curve into an S shape. In some cases, the vocal cords atrophy and the person has difficulty swallowing and speaking. Charcot-Marie-Tooth patients are often shorter than average due to the muscular problems. People with the disease are particularly prone to gastrointestinal problems.
Treatment for Charcot-Marie-Tooth disease is focused on alleviating the symptoms, because there is no cure, though researchers have begun to investigate the possibility of using an analog to a growth factor ordinarily produced by the cells but that Charcot-Marie-Tooth disease interferes with. People with the condition often require orthopedic devices for mobility, but doctors use physical therapy and occupational therapy to avoid or forestall this. Other assistive devices can be helpful in allowing patients to do everyday tasks.
Now, however, a new study may put doctors on the road to a cure. Zebrafish are commonly used in medical research because they are similar to humans in surprisingly many respects, and the zebrafish complete genome is known, making mutations easy to both introduce and recognize. One research team has begun using zebrafish to explore Charcot-Marie-Tooth disorder, and have learned that motor neurones are involved in the condition. This suggests possible treatment approaches along the line of other motor neuron diseases.