About Myotonic Dystrophy
The New York Center for Rare Diseases supports the mission and guidelines of the Genetic and Rare Diseases Information Center (GARD). The following information is provided by the NIH.
Summary
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 genetic changes (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.
Causes
What Causes This Disease?
Genetic Mutations: Myotonic dystrophy is caused by genetic mutations, also known as pathogenic variants. Genetic mutations can be hereditary, when parents pass them down to their children, or they may occur randomly when cells are dividing. Genetic mutations may also result from contracted viruses, environmental factors, such as UV radiation from sunlight exposure, or a combination of any of these.
If you suspect you may have this disease, you may want to start collecting your family health history. Information such as other family members who have had similar symptoms, when their/your symptoms first appeared, or exposures to any potential disease-causing environmental factors should be discussed with your medical team.