What Is Duchenne Muscular Dystrophy ( DMD ) ?

Muscular dystrophies are a group of diseases that make muscles weaker and less flexible over time. Duchenne muscular dystrophy (DMD) is the most common type. It’s caused by flaws in the gene that controls how the body keeps muscles healthy.

The disease almost always affects boys, and symptoms usually begin early in childhood. Children with DMD have a hard time standing up, walking, and climbing stairs. Many eventually need wheelchairs to get around. They can also have heart and lung problems.

Although there isn’t a cure, the outlook for people with DMD is better than it has ever been. Years ago, children with the disease usually didn’t live beyond their teens. Today, they live well into their 30s, and sometimes into their 40s and 50s. There are therapies that can ease symptoms, and researchers are looking for new ones, as well.

Causes

DMD is caused by a problem in one of your genes. Genes contain the information your body needs to make proteins, which carry out many different body functions.

If you have DMD, the gene that makes a protein called dystrophin is broken. This protein normally keeps muscles strong and protects them from injury.

The condition is more common in boys because of the way parents pass DMD genes to their children. It’s what scientists call a sex-linked disease because it’s connected to the groups of genes, called chromosomes, that determine if a baby is a boy or a girl.

It’s rare, but sometimes people who don’t have a family history of DMD get the disease when their genes get defects on their own.

Symptoms

If your child has DMD, you’ll probably notice the first signs before he turns 6 years old. Muscles in the legs are usually some of the first affected, so he’ll probably start to walk much later than other children his age. Once he can walk, he may fall down often and have trouble climbing stairs or getting up from the floor. After a few years, he might also begin to waddle or walk on his toes.