GENE DISCOVERY PROVIDES LINK BETWEEN NEUROLOGICAL DISORDERS

In the July issue of The American Journal of Human Genetics, Mersiyanova and colleagues of the Research Centre for Medical Genetics in Moscow present results showing that mutations in the neurofilament light gene are associated with CMT, one of the most common inherited disorders in humans. This neurological disorder affects peripheral nerves and leads to progressive weakness and atrophy of muscles. Neurofilament light is a component of neurofilament, which is important for the structure and function of nerve axons. The neurofilament proteins are also involved in several other neurological disorders, including Parkinson, Alzheimer and Lou Gehrig's disease. In CMT, the defects in neurofilament initiate a chain of events that leads to axon degeneration and muscle denervation.

The other three genes known to lead to Charcot-Marie-Tooth are all closely related to myelin, the protective sheath surrounding nerve axons. Mutations in these genes lead to demyelination, which in turn results in axonal loss and muscle denervation. Thus, all of the CMT-associated genes that have been identified encode products that are essential for the maintenance of peripheral nervous system structure and function. Mutations in any of these genes initiate a pathological process that is common between the different forms of the disease. Characterization of additional CMT-associated genes and steps in the pathological process leading to this disorder will give better insight into the normal maintenance of peripheral nervous system function, which may help in treating not only CMT, but also the other disorders associated with neurofilament defects.

For the full text of this article, entitled "A new variant of Charcot-Marie-Tooth disease type 2 (CMT2E) is probably the result of a mutation in the neurofilament light gene",see the "July 2000"section in the electronic edition of The American Journal of Human Genetics at http://www.ajhg.org.

For more information, contact Dr. Irina Mersiyanova at the Research Centre for Medical Genetics, Moscow. Tel: (7-095)936-9259. Fax: (7-095)936-9459. Email: dnalab@orc.ru

Contributed by Dr. Kate Beauregard, The American Journal of Human Genetics, Tel: (404)712-9985. Email: kbeaure@emory.edu

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