What is Duchenne Muscular Dystrophy?

Duchenne muscular dystrophy is a disease that affects mostly boys, causes progressive muscle weakness and gradually steals boys’ ability to walk.

Who is affected?
Duchenne muscular dystrophy (DMD) is an X-linked disease. That means that it’s a genetic disease carried on X-chromosome and typically inherited through the mom. Because of this mechanism, Duchenne muscular dystrophy typically affects boys. It’s estimated that approximately one in 3,500-5,000 boys have Duchenne muscular dystrophy.

What are the symptoms?
Duchenne muscular dystrophy is a disease of the muscles. Symptoms present early in childhood and include the following:

• Low muscle tone
• Enlarged calf muscles
• Delay in meeting developmental milestones
• Progressive muscle weakness
• A waddling gait
• Presence of a Gower’s maneuver (illustration below)

How is Duchenne diagnosed?
A blood test called creatine kinase, or CK, can be used to screen patients for Duchenne. An extremely elevated CK is indicative of muscle breakdown and possible muscular dystrophy. However, CK isn’t specific and can be elevated in many different types of muscular dystrophy. In years past, invasive muscle biopsy was required to confirm a diagnosis of Duchenne. However, with advancement in the field of genetics, providers can now easily order genetic testing to look for errors in the gene that causes Duchenne muscular dystrophy. This is the gold standard in the diagnosis of DMD and can be performed on DNA extracted from blood.

What’s it like for families living with a loved one affected by Duchenne?
Living with Duchenne, or living with a son, brother, or other loved one who has Duchenne, poses different challenges throughout the lifespan. When boys with DMD are young, they benefit from physical therapy, stretching, and may need an individualized education plan at school. As boys grow older, their needs change. They require assistive devices both inside and outside of the home, including lifts, power wheelchairs, and modified beds. Aides at home or in the classroom are helpful in the completion of activities of daily living. Later in life, men may require devices to assist with breathing or eating.

What treatment is available?
Unfortunately, there is no cure for Duchenne, and there are very few approved treatments to improve symptoms and prolong the lives of boys and men with this disease. Treatments include the following:

• Corticosteroids: A proven intervention to change the natural history of the disease and prolong the ability to walk by approximately two years.
• Medications to manage stress on the heart, including beta blockers and ACE-inhibitors: These drugs can help to prevent the development of scar tissue in the heart.
• Cough-assist devices and BiPAP machines improve respiratory function when muscles that support breathing become weak.
• Bone health: Boys and men with Duchenne are at risk for broken bones, so it’s imperative to keep their bones as healthy as possible. Vitamin D and calcium help, but sometimes use of a drug called bisphosphonates is needed to increase bone density.

What’s in the pipeline?
Luckily, Nationwide Children’s Hospital is leading the way in delivering effective treatments that will slow the progression of Duchenne. Exon skipping, nonsense suppression, anti-inflammatory drugs, gene editing, and gene therapy are all exciting and promising therapies currently under development around the world. The Center for Gene Therapy in Nationwide Children’s Research Institute participates in many multi-site studies, as well as trials that are only available at Nationwide Children’s. For the first time, we’re able to provide hope to families in the form of treatments that may one day cure their sons.