Learning About Charcot-Marie-Tooth Disease
What do we know about Charcot-Marie-Tooth disease?
Charcot-Marie-Tooth disease (CMT) is an inherited neurological disease characterized by a slowly progressive degeneration of the muscles in the foot, lower leg, hand, and forearm, and a mild loss of sensation in the limbs, fingers, and toes. The first sign of CMT is generally a high arched foot or gait disturbances.
Other symptoms of the disorder may include foot-bone abnormalities such as high arches and hammer toes, problems with hand function and balance, occasional lower leg and forearm muscle cramping, loss of some normal reflexes, occasional partial sight and/or hearing loss, and, in some individuals, scoliosis (curvature of the spine).
People with CMT disease usually begin to experience symptoms in adolescence or early adulthood. There is no cure for the disease, but there are treatment options, including physical therapy and bracing. Life expectancy is usually normal.
CMT disease can be divided into two classes, depending on where the dysfunction occurs in the peripheral nerves:
- In CMT type 1, the peripheral nerves' axons - the part of the nerve cell that transmits electrical signals to the muscles - lose their protective outer coverings, their myelin sheaths. This disrupts the axons' function.
- In CMT type 2, the axons' responses are diminished due to a defect within the axons themselves. CMT type 2, the less common of the two classes, can be further separated into at least six subtypes, caused by defects in different genes.
Is there a gene implicated in Charcot-Marie-Tooth?
The newly discovered GARS gene (see Gene Discovery Opens Door to Further Research In Inherited Neurological Disorders [News Release]) is implicated in CMT type 2D, a form of CMT that primarily affects the hands and the forearms. CMT type 2D is inherited in an autosomal dominant fashion.
Even though the GARS gene is implicated in only two specific types of CMT, this discovery will guide researchers in studying other forms of these diseases, as well as other neurological disorders.
Because carpal tunnel syndrome affects the hands and the forearms, scientists may now investigate whether the GARS gene plays some role in this disorder. And two defective forms of the gene implicated in Lou Gehrig's disease are known to interact with a GARS family member.
Ultimately, the GARS gene and its family may provide a rich new resource for scientists investigating inherited and non-inherited neurological diseases.
NHGRI Clinical Research on Charcot-Marie-Tooth Disease
Currently, NHGRI is not conducting studies on Charcot-Marie-Tooth Disease
Additional Resources for Charcot-Marie-Tooth Disease
- Charcot Marie Tooth Disease [ghr.nlm.nih.gov]
Summary FAQ from the Genetics Home Reference at the National Library of Medicine.
- Charcot Marie Tooth Disease [rarediseases.org]
Information from The National Organization for Rare Disorders (NORD).
- Online Mendelian Inheritance in Man (OMIM) [ncbi.nlm.nih.gov]
A searchable database from the National Center for Biotechnology Information.
- eMedicine Journal [eMedicine.com]
There are two articles by Divakara Kedlaya, MBBS, Associate Professor, Department of Physical Medicine and Rehabilitation, Loma Linda University Medical Center, about Charcot-Marie-Tooth Disease at the eMedicine Journal Web site. One last updated in May 2002 and another last updated on December 2001
- Charcot-Marie-Tooth Association [charcot-marie-tooth.org]
Additional information about Charcot-Marie-Tooth and supportive resources.
- Heredity Neuropathy Foundation [hnf-cure.org]
Dedicated to finding a cure for Charcot-Marie-Tooth disease (CMT) while providing support and services for those living with CMT and their families.
- Charcot-Marie-Tooth Fact Sheet (NINDS) [ninds.nih.gov]
A comprehensive information page on Charcot-Marie-Tooth disease from NINDS.
- Charcot-Marie-Tooth [nlm.nih.gov]
A list of links including clinical trials, testing and research from Medline Plus
- NINDS Charcot-Marie-Tooth Disease Information Page [ninds.nih.gov]
From the National Institute of Neurological Disorders and Stroke
- National Center for Biotechnology Information [ncbi.nlm.nih.gov]
An information page about Charcot-Marie-Tooth disease.
- Charcot-Marie-Tooth Disease [rarediseases.info]
Information from the Genetics and Rare Diseases Information Center.
- Finding Reliable Health Information Online
A listing of information and links for finding comprehensive genetics health information online.
Last Updated: December 15, 2010