As a result of the way it's inherited, Duchenne Muscular Dystrophy (MD) mostly affects boys. Girls can occasionally be affected, although the condition tends to be milder in females.
Children with Duchenne MD usually start to have noticeable symptoms between one and three years of age. The muscles around their pelvis and thighs tend to be affected first and often appear bulkier than normal.
A child with Duchenne MD may:
Children with Duchenne MD may need a wheelchair by the time they're 8-14 years old, as their muscles weaken and they lose the ability to walk. They can also develop scoliosis, where the spine begins to curve sideways. This can lead to one shoulder or hip being higher than the other.
By their mid-teens, some people with Duchenne MD will develop dilated cardiomyopathy. This condition affects the heart muscles, causing the heart's chambers to enlarge and the walls to get thinner.
By their late-teens or early 20s, people with Duchenne MD may start to have breathing problems. The condition can also affect the intercostal muscles (muscle tissue between the ribs) and the diaphragm (the large, thin sheet of muscle between the chest and abdomen).
Once the heart and respiratory muscles are damaged, Duchenne MD becomes life-threatening. With medical care, most people with Duchenne MD die from heart or respiratory failure before or during their 30s.