This information is provided by the National Institutes of Health (NIH) Genetic and Rare Diseases Information Center (GARD).
Myotonic dystrophy is a disease that affects the muscles and other body systems. It is the most common form of muscular dystrophy that begins in adulthood, usually in a person’s 20s or 30s. This disease is characterized by progressive muscle loss and weakness. Myotonic dystrophy may be further classified into two types, and the two types may affect different muscles. People with myotonic dystrophy usually have prolonged muscle tensing (myotonia) and are not able to relax certain muscles after use. The severity of the disease may vary among affected people, even among members of the same family.
Myotonic dystrophy is caused by mutations (changes) in the DMPK gene or the CNBP (ZNF9) gene depending on the specific type of myotonic dystrophy. The disease is inherited in an autosomal dominant manner. Myotonic dystrophy may be diagnosed when a healthcare provider observes signs and symptoms of the disease, and the diagnosis may be confirmed with tests of muscle function and genetic testing. Treatment is based on each person’s specific signs and symptoms and may include physical therapy, pain management with medication, and consultation with specialists.
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