source: Muscular Dystrophy Association
Duchenne muscular dystrophy (DMD) is the most common form of muscular dystrophy. It is a genetic disorder characterized by progressive weakness and degeneration of the skeletal muscles that control movement. Duchenne affects approximately 1 in 5,000 live male births. It is estimated that about 20,000 children are diagnosed with Duchenne globally each year.
DMD is classified as a dystrophinopathy, a muscle disease that results from the deficiency of a protein called dystrophin. In Duchenne, a mutation in the DMD gene interferes with the production of the dystrophin protein, which is needed to form and maintain healthy muscle. Lack of the dystrophin protein in muscle cells causes them to be fragile and easily damaged.
Because the DMD gene is located on the X-chromosome, it primarily affects males, while females typically are carriers. However, some females can experience varying degrees of physical Duchenne symptoms and are therefore called manifesting carriers.