Duchenne muscular dystrophy (DMD) is one of a group of muscular dystrophies characterized by the enlargement of muscles. DMD is one of the most prevalent types of muscular dystrophy and is characterized by rapid progression of muscle degeneration that occurs early in life. All are X-linked and affect mainly males—an estimated 1 in 3500 boys worldwide.

The gene for DMD, found on the X chromosome, encodes a large protein—dystrophin. Dystrophin is required inside muscle cells for structural support; it is thought to strengthen muscle cells by anchoring elements of the internal cytoskeleton to the surface membrane. Without it, the cell membrane becomes permeable, so that extracellular components enter the cell, increasing the internal pressure until the muscle cell "explodes" and dies. The subsequent immune response can add to the damage.

A mouse model for DMD exists and is proving useful for furthering our understanding on both the normal function of dystrophin and the pathology of the disease. In particular, initial experiments that increase the production of utrophin, a dystrophin relative, in order to compensate for the loss of dystrophin in the mouse are promising and may lead to the development of effective therapies for this devastating disease.