How is Muscular Dystrophy Diagnosed?
- A muscle biopsy (the removal and exam of a small sample of muscle tissue)
- DNA (genetic) testing
- Electromyography or nerve conduction tests (which use electrodes to test muscle and/or nerve function)
- Blood enzyme tests (to look for the presence of creatine kinase, which reveals deterioration of muscle fibers)
For Duchenne and Becker muscular dystrophies, muscle biopsy may show whether dystrophin, a muscle protein, is missing or abnormal, and DNA testing is used to analyze the condition of the related gene. Genetic testing also is available for some forms of muscular dystrophy.
What Are the Treatments for Muscular Dystrophy?
There is no cure for any form of muscular dystrophy, but medications and therapy can slow the course of the disease. Human trials of gene therapy with the dystrophin gene are on the near horizon. For instance, scientists are researching ways to insert a working dystrophin gene into the muscles of boys with Duchenne and Becker muscular dystrophies.
Researchers are investigating the potential of certain muscle-building medicines to slow down or reverse the progression of muscular dystrophy. Other trials are looking into the effects of the dietary supplements creatine and glutamine on muscle energy production and storage.
Conventional Medicine for Muscular Dystrophy
- Exercise and physical therapy can minimize abnormal or painful positioning of the joints and may prevent or delay curvature of the spine. Respiratory care, deep breathing, and coughing exercises are often recommended.
- Canes, powered wheelchairs, and other rehabilitative devices can help those with MD maintain mobility and independence.
- Surgery can sometimes relieve muscle shortening. In Emery-Dreifuss and myotonic muscular dystrophy, it's often necessary to surgically implant a cardiac pacemaker.
In some cases, disease progression can be slowed or symptoms relieved with medication:
- In Duchenne muscular dystrophy, corticosteriods may slow muscle destruction. Eteplirsen (Exondys 51) has been approved to treat DMD. It is an injection medication that helps treat individuals with a specific mutation of the gene that leads to DMD. The most common side effects are balance problems and vomiting. Although the drug increases dystrophin production, which would predict improvement in muscle function, this has not yet been shown.
- In myotonic muscular dystrophy, phenytoin and mexiletine (Mexitil) can treat delayed muscle relaxation.
Medications also can be prescribed for some muscular dystrophy-related heart problems.
Can You Prevent Muscular Dystrophy?
If you have a family history of muscular dystrophy, you may want to consult a genetic counselor before having children. The odds of passing the disease on to your children range from 25% to 50%. Carriers -- typically sisters and mothers of those with MD -- usually don't have the disease, but they may exhibit mild symptoms that give hints of it. They can pass the disease on to their children; their sons will get the disease and half the time, their daughters become carriers. For Duchenne and Becker muscular dystrophies, protein and DNA tests can identify carriers, and DNA probes can provide prenatal diagnosis. Tests for carriers of other forms of muscular dystrophy are under development.