Charcot-Marie-Tooth disease, Type 4B1: CMT is an inherited neurological disease characterized by the gradual degeneration of nerves which starts in the hands and feet and results in progressive numbness, muscle weakness and loss of function. Type 4B1 has an autosomal recessive inheritance and involves a defect in MTMR2 gene on chromosome 11.
* Slow running during childhood * High foot arches * Hammer toes * Foot weakness * Hand weakness
Genetic tests, done by drawing blood, are available to test for many, but not all, of the common chromosomal defects causing CMT. A positive genetic test can provide definitive diagnosis and provide useful information for family planning. However, a negative result does not rule out CMT since some forms cannot yet be tested by DNA sampling. Currently, 18 types can be identified by DNA testing: 1A, 1B, 1C, 1D, 1E, 1F, 1X, 2A, 2E, 2I, 2J, 2K, 4A, 4E, 4F, HNPP, CHN, and DSN. Click here to view a booklet on genetic testing and CMT prepared by Athena Diagnostics.