Muscular dystrophy is a group of diseases that cause muscles throughout the body to deteriorate. The diseases, also known as MD, result from genetic mutations. These mutations cause a decrease in the production of proteins that are necessary to build and maintain muscle tissue. Weakness typically begins in the muscles involved in movement and may limit a patient’s mobility. Eventually the weakness progresses to the heart and the muscles of the lungs and may cause these organs to fail.

Researchers have divided MD into 30 diseases classified into nine groups. They are all characterized by muscle weaknesses, but differ in the typical age when symptoms begin and which muscle groups are affected. The disease groups are:

• Duchenne MD
• Myotonic MD
• Facioscapulohumeral MD
• Becker MD
• Congenital MD
• Emery-Dreifuss MD
• Limb-girdle MD
• Distal MD
• Oculopharyngeal MD

The genetic mutations that cause MD are usually inherited. A parent with a family history of the disease may have up to a 50 percent chance of passing it to a child. Some mutations that cause MD are found on the genetic material (chromosomes) that determine gender. This means that those forms of MD may occur only in males, or may be more prevalent or severe in males.

A diagnosis of MD is often based on the onset of signs and symptoms in addition to a family history of the disease. Other tests may be necessary to confirm this diagnosis and eliminate other potential causes of muscular weakness. These might include blood tests, urine tests, tissue biopsies and imaging tests (e.g., MRI scans) of the affected muscles.

Upon diagnosis, supportive treatment may begin to reduce the patient’s symptoms and delay muscle degeneration. At present, there is no cure. Treatment often consists of medication, physical and speech therapy and use of orthopedic devices.