In people with MD, though, these genes have wrong information or leave out important information, so the body can't make these proteins properly. Most kids with MD have Duchenne MD. Kids with Duchenne MD look and act just like other kids when they're babies. But when they're between 2 and 6 years old, the muscles in their arms, legs, and pelvis (hips) begin to get weaker. The first signs of weakness might be trouble with running, going up the stairs, or getting up off of the floor. A boy with Duchenne MD will have trouble walking and eventually will stop walking. The boy also might have trouble feeding himself, difficulty breathing, and trouble with his
