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    Myotonia Congenita

    Important
    It is possible that the main title of the report Myotonia Congenita is not the name you expected.

    Disorder Subdivisions

    • Thomsen Disease (THD); Myotonia Congenita, Autosomal Dominant
    • Becker Disease; Myotonia Congenita, Autosomal Recessive (MCR); Generalized

    General Discussion

    Myotonia congenita is a rare genetic disorder in which an abnormality of voluntary (skeletal) muscle fiber membranes causes an unusually exaggerated response to stimulation (hyperexcitability). As a result, affected individuals have difficulty relaxing certain muscles after contracting them (myotonia), muscle stiffness (rigidity), and associated symptoms. Such symptoms tend to occur when attempting to move certain muscles after rest. In many cases, individuals with myotonia congenita also have abnormal enlargement of the muscles (hypertrophy), resulting in a "herculean" or "body-builder like" appearance.

    Two main forms of myotonia congenita have been described: Thomsen disease and Becker disease. In individuals with Thomsen disease, symptoms and findings such as myotonia, associated muscle rigidity, and abnormal muscle enlargement may become apparent from infancy to approximately two to three years of age. In many cases, muscles of the eyelids, hands, and legs may be most affected. Thomsen disease is transmitted as an autosomal dominant trait.

    In those with Becker disease, symptoms most commonly become apparent between the ages of four and 12 years. As in Thomsen type myotonia congenita, affected individuals develop myotonia, associated muscle rigidity, and abnormal muscle enlargement (hypertrophy). The symptoms tend to remain constant, with little progression. Becker disease is inherited as an autosomal recessive trait.

    Resources

    Malignant Hyperthermia Association of the United States
    1 North Main St
    PO Box 1069
    Sherburne, NY 13460
    USA
    Tel: (607)674-7901
    Fax: (607)674-7910
    Email: info@mhaus.org
    Internet: http://www.mhaus.org

    Muscular Dystrophy Association
    3300 East Sunrise Drive
    Tucson, AZ 85718-3208
    USA
    Tel: (520)529-2000
    Fax: (520)529-5300
    Tel: (800)572-1717
    Email: mda@mdausa.org
    Internet: http://www.mda.org/

    NIH/National Institute of Arthritis and Musculoskeletal and Skin Diseases
    Information Clearinghouse
    One AMS Circle
    Bethesda, MD 20892-3675
    USA
    Tel: (301)495-4484
    Fax: (301)718-6366
    Tel: (877)226-4267
    TDD: (301)565-2966
    Email: NIAMSinfo@mail.nih.gov
    Internet: http://www.niams.nih.gov/

    NIH/National Institute of Neurological Disorders and Stroke
    P.O. Box 5801
    Bethesda, MD 20824
    Tel: (301)496-5751
    Fax: (301)402-2186
    Tel: (800)352-9424
    TDD: (301)468-5981
    Internet: http://www.ninds.nih.gov/

    Genetic and Rare Diseases (GARD) Information Center
    PO Box 8126
    Gaithersburg, MD 20898-8126
    Tel: (301)251-4925
    Fax: (301)251-4911
    Tel: (888)205-2311
    TDD: (888)205-3223
    Internet: http://rarediseases.info.nih.gov/GARD/

    Child Neurology Foundation
    2000 West 98th Street
    Bloomington, MN 55431
    USA
    Tel: (952)641-6100
    Fax: (952)881-6276
    Tel: (877)263-5430
    Email: jstone@childneurologyfoundation.org
    Internet: http://www.childneurologyfoundation.org

    For a Complete Report:

    This is an abstract of a report from the National Organization for Rare Disorders (NORD). A copy of the complete report can be downloaded free from the NORD website for registered users. The complete report contains additional information including symptoms, causes, affected population, related disorders, standard and investigational therapies (if available), and references from medical literature. For a full-text version of this topic, go to www.rarediseases.org and click on Rare Disease Database under "Rare Disease Information".

    The information provided in this report is not intended for diagnostic purposes. It is provided for informational purposes only. NORD recommends that affected individuals seek the advice or counsel of their own personal physicians.

    It is possible that the title of this topic is not the name you selected. Please check the Synonyms listing to find the alternate name(s) and Disorder Subdivision(s) covered by this report

    This disease entry is based upon medical information available through the date at the end of the topic. Since NORD's resources are limited, it is not possible to keep every entry in the Rare Disease Database completely current and accurate. Please check with the agencies listed in the Resources section for the most current information about this disorder.

    For additional information and assistance about rare disorders, please contact the National Organization for Rare Disorders at P.O. Box 1968, Danbury, CT 06813-1968; phone (203) 744-0100; web site www.rarediseases.org or email orphan@rarediseases.org

    Last Updated: 9/17/2007
    Copyright 1987, 1990, 1996, 1997, 2001, 2003, 2006, 2007 National Organization for Rare Disorders, Inc.

    WebMD Medical Reference from the National Organization for Rare Disorders

    Last Updated: May 28, 2015
    This information is not intended to replace the advice of a doctor. Healthwise disclaims any liability for the decisions you make based on this information.

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