What is Duchenne muscular dystrophy?

Duchenne muscular dystrophy (DMD) is the most common lethal genetic disorder diagnosed during childhood. It is a progressive muscle disorder that causes loss of muscle function and independence. To date, there is no cure.

Boys afflicted with DMD are born with the inability to produce the protein "dystrophin" as a result of a genetic problem in their dystrophin gene. The dystrophin protein is necessary to protect and provide a sort of "shock absorber" for their muscles. Without it their muscle cells are unprotected and eventually waste away. Because the dystrophin gene is found in the X chromosome it primarily affects boys. Girls who are affected are generally carriers.

Symptoms / Prognosis

DMD symptoms usually begin between the ages of one and three. Boys may not start walking until later than expected. Pre- schoolers may be unable to run and jump like other children their age. The disorder is generally diagnosed between the age of four and six.

As the disorder progresses, boys with DMD get weaker and can't walk as far, or as fast, as other children their age. They may develop a waddling walk, and fall down occasionally. They also display an unusual way of getting  to a standing position when they are seated on the floor. This is called Gower's sign (maneuver).

Most boys slowly lose their ability to walk between ten and fifteen years of age and will require the use of a wheelchair. By this time the disorder will begin affecting upper body movement (weakness in arms, hands). As boys go through their teenage years their heart and respiratory functions generally weaken requiring intervention such as heart medications and breathing assist devices. Most boys will eventually lose their battle with this disorder in early adulthood.