About Myotonic Dystrophy
Myotonic dystrophy (DM) is a rare genetic disorder that can cause problems with many systems in the body. The various forms of myotonic dystrophy are caused by changes at different sites in the DNA of an individual (i.e. different gene mutations). The first type, often referred to as DM1, affects an estimated 1 in 8,000 people worldwide, or nearly 40,000 individuals in the US alone. Since the gene mutation that causes the second type, DM2, was located just a few years ago, its prevalence is still unknown. Other possible types, caused by different mutations, are currently being investigated.
Muscle issues are often --- although not always --- one of the first complaints of adult patients, characterized by the following:
- muscle weakness, most commonly seen in the arms, face, neck and often legs
- progressive muscle wasting (atrophy)
- stiffness and difficulty relaxing a muscle (myotonia)
However, classifying myotonic dystrophy simply as a muscle disorder is misleading because of the range of systems that can be affected.
The range of systems affected and the severity of symptoms seen can vary greatly between patients, even in the same family. In addition to muscle problems, issues with respiratory function, heart abnormalities, cataracts, cognitive impairment and personality abnormalities are often seen. However, an affected person does not typically exhibit all, or even most, of the possible symptoms. Often, the disease is mild and only minor muscle weakness or cataracts are seen late in life. At the opposite end of the spectrum, life-threatening neuromuscular, cardiac and pulmonary complications can occur in the most severe cases when children are born with the congenital form of the disease. Regardless of the form of DM or the severity of symptoms experienced by a patient, individuals with myotonic dystrophy can have severe reactions to anesthesia and should be monitored carefully whenever anesthesia is administered. Click here for a full listing of Symptoms of Myotonic Dystrophy.
Myotonic dystrophy is categorized by different types and sub-types. Click here to learn more.
Additional information is available on the Cause of Myotonic Dystrophy, Diagnosis of Myotonic Dystrophy and Disease Management for all disease types.
Learn about the historical background of the discovery and description of the understanding of myotonic dystrophy