Diseases & Conditions


A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

Myotonia Congenita


Synonyms of Myotonia Congenita

    Disorder Subdivisions

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


    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.

    Organizations related to Myotonia Congenita
    • MUMS (Mothers United for Moral Support, Inc) National Parent-to-Parent Network
      150 Custer Court
      Green Bay WI 54301-1243
      Phone #: 920-336-5333
      800 #: 877-336-5333
      e-mail: mums@netnet.net
      Home page: http://www.netnet.net/mums/
    • Malignant Hyperthermia Association of the United States (MHAUS)
      11 East State Street
      Sherburne NY 13460-1069
      Phone #: 607-674-7901
      800 #: --
      e-mail: info@mhaus.org
      Home page: http://www.mhaus.org
    • Muscular Dystrophy Association
      3300 E. Sunrise Dr
      Tucson AZ 85718
      Phone #: 520-529-2000
      800 #: 800-344-4863
      e-mail: mda@mdausa.org
      Home page: http://www.mdausa.org
    • NIH/National Arthritis and Musculoskeletal and Skin Diseases Information Clearinghouse
      1 AMS Circle
      Bethesda MD 20892-3675
      Phone #: 301-495-4484
      800 #: 877-226-4267
      e-mail: NIAMSinfo@mail.nih.gov
      Home page: http://www.niams.nih.gov/Health_Info
    • National Institute of Neurological Disorders and Stroke (NINDS)
      31 Center Drive
      Bethesda MD 20892-2540
      Phone #: 301-496-5751
      800 #: 800-352-9424
      e-mail: braininfo@ninds.nih.gov
      Home page: http://www.ninds.nih.gov/



    For a Complete Report

    This is an abstract of a report from the National Organization for Rare Disorders, Inc. ? (NORD). A copy of the complete report can be obtained for a small fee by visiting the NORD website. The complete report contains additional information including symptoms, causes, affected population, related disorders, standard and investigational treatments (if available), and references from medical literature. For a full-text version of this topic, see http://www.rarediseases.org/search/rdblist.html