Find out about the most common types of this brain disease, including Duchenne muscular dystrophy, and options for treatment
Muscular dystrophy is a genetic brain disease that affects the muscles and causes them to weaken. This group of disorders includes more than 30 different genetic diseases, which can vary based on when symptoms begin, the type and severity of muscle weakness, how quickly the disease progresses, and the chances of passing along the genetic disease to children or grandchildren.
The most common type of muscular dystrophy is Duchenne muscular dystrophy (DMD), which affects children. DMD primarily affects boys: One in 3,500 males worldwide develop DMD. Girls in affected families can also inherit and pass on the gene for DMD. DMD is not more common among any specific race or ethnicity.
DMD is caused by a genetic defect that prevents the production of a protein called dystrophin, which helps maintain muscle structure and strength. When this protein is missing, the muscle degenerates and becomes inflamed. Then an immune response starts that leads to further inflammation and muscle weakness—a continuous, destructive cycle.
Other common types of muscular dystrophy include facioscapulohumeral muscular dystrophy, which begins in the teenage years and progresses more slowly, and myotonic dystrophy, which is the most common form to affect adults and causes cataracts, heart abnormalities, and difficulty relaxing muscles.
Symptoms and Diagnosis
Muscle weakness is the primary sign of muscular dystrophy. Its progression can affect a person’s ability to move, walk, and breathe. Symptoms can start at different ages and vary in severity and how fast they progress.
In the case of DMD, symptoms generally start between ages 3 and 5. Muscle weakness typically begins in the upper arms and upper legs and can spread to the heart, lungs, throat, stomach, intestines, and spine. DMD’s rapid progression of muscle weakness means patients are often unable to walk by age 12. Eventually, they require a respirator to breathe.
The progression of the disease can vary depending on the type of muscular dystrophy. Some forms cause a rapid progression of muscle weakness, while others result in a slower progression over a normal lifespan. Symptoms also vary from mild to severe, including losing the ability to walk.
For boys with Duchenne that do not have a family history of muscular dystrophy, it can take an average of 2.5 years from the time a caregiver notices the first symptom to the point of diagnosis via muscle biopsy or DNA testing. The average age for diagnosis is 5 years old.
Genetic testing may provide more information about the specific cause and help identify the type of muscular dystrophy. It can also give patients an understanding of potential future complications of their disease as it progresses, as well as the chances of passing on any gene mutations to children.
There’s no prevention, cure, or long-term treatment for muscular dystrophy. Treatment options to slow the progression of muscular dystrophy depend on the type of muscle degeneration.
Physical and occupational therapy may be helpful for some patients. If the disease affects a person’s respiratory muscles, they may need to use some type of assisted ventilation. But if it affects their cardiac muscles, a pacemaker may be used to regulate muscle activity.
For those who have an absence or mutation of the dystrophin protein, treatment may include injections of drugs that boost production of this protein. Other drug therapies include corticosteroids, anticonvulsants, immunosuppressants, and antibiotics to combat respiratory infection. While steroids have many benefits, they can also have significant side effects, including high blood pressure and difficulty sleeping. Research has shown that creatine, a supplement used by athletes and weightlifters, can also help rebuild muscle strength and may prevent side effects of corticosteroids for people with DMD.
In 2019, the American Brain Foundation awarded Jerry Mendell, MD, FAAN its “Cure One, Cure Many” award for his research into a one-time treatment for children with spinal muscular atrophy. His treatment offers what is essentially a cure for an otherwise fatal disease and can be built upon to treat patients with Duchenne and limb-girdle muscular dystrophy. Dr. Mendell’s research underscores the interconnectedness of brain diseases and the importance of studying the whole brain.
The American Brain Foundation was founded to bring researchers and donors together in the fight against brain disease. Learn more about muscular dystrophy and other brain diseases or make a gift to support groundbreaking brain disease research.