• Enzyme tests. Damaged muscles release enzymes, such as creatine kinase (CK), into your blood. In a person who hasn't had a traumatic injury, high blood levels of CK suggest a muscle disease.

• Genetic testing. Blood samples can be examined for mutations in some of the genes that cause types of muscular dystrophy.

• Muscle biopsy. A small piece of muscle can be removed through an incision or with a hollow needle. Analysis of the tissue sample can distinguish muscular dystrophies from other muscle diseases.

• Heart-monitoring tests (electrocardiography and echocardiogram). These tests are used to check heart function, especially in people diagnosed with myotonic muscular dystrophy.

• Lung-monitoring tests. These tests are used to check lung function.

• Electromyography. An electrode needle is inserted into the muscle to be tested. Electrical activity is measured as you relax and as you gently tighten the muscle. Changes in the pattern of electrical activity can confirm a muscle disease.

Although there's no cure for any form of muscular dystrophy, treatment for some forms of the disease can help extend the time a person with the disease can remain mobile and help with heart and lung muscle strength. Trials of new therapies are ongoing.

People with muscular dystrophy should be monitored throughout their lives. Their care team should include a neurologist with expertise in neuromuscular diseases, a physical medicine and rehabilitation specialist, and physical and occupational therapists.

Several types of therapy and assistive devices can improve the quality and sometimes the length of life in people who have muscular dystrophy. Examples include:

• Range-of-motion and stretching exercises. Muscular dystrophy can restrict the flexibility and mobility of joints. Limbs often draw inward and become fixed in that position. Range-of-motion exercises can help to keep joints as flexible as possible.

• Exercise. Low-impact aerobic exercise, such as walking and swimming, can help maintain strength, mobility and general health. Some types of strengthening exercises also might be helpful. But it's important to talk to your doctor first because some types of exercise might be harmful.

• Braces. Braces can help keep muscles and tendons stretched and flexible, slowing the progression of contractures. Braces can also aid mobility and function by providing support for weakened muscles.

• Mobility aids. Canes, walkers and wheelchairs can help maintain mobility and independence.

• Breathing assistance. As respiratory muscles weaken, a sleep apnea device might help improve oxygen delivery during the night. Some people with severe muscular dystrophy need to use a machine that forces air in and out of their lungs