National Organization for Rare Disorders, Inc.
It is possible that the main title of the report Myotonia Congenita is not the name you expected.
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.
Child Neurology Foundation
- 201 Chicago Ave, #200
- Minneapolis, MN 55415
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Genetic and Rare Diseases (GARD) Information Center
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- Tel: (301)251-4925
- Fax: (301)251-4911
- Tel: (888)205-2311
- Website: http://rarediseases.info.nih.gov/GARD/
Malignant Hyperthermia Association of the United States
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- PO Box 1069
- Sherburne, NY 13460
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Muscular Dystrophy Association
- 3300 East Sunrise Drive
- Tucson, AZ 85718-3208
- Tel: (520)529-2000
- Fax: (520)529-5300
- Tel: (800)572-1717
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- Website: http://www.mda.org/
NIH/National Institute of Arthritis and Musculoskeletal and Skin Diseases
- Information Clearinghouse
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- Bethesda, MD 20892-3675
- Tel: (301)495-4484
- Fax: (301)718-6366
- Tel: (877)226-4267
- Email: NIAMSinfo@mail.nih.gov
- Website: 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
- Website: http://www.ninds.nih.gov/
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
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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 email@example.com
Last Updated: 12/9/1969
Copyright 2007 National Organization for Rare Disorders, Inc.
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