What are the effects of DMD? For children with DMD, muscle weakness starts in early childhood. It is first noticed between 2 and 5 years old. The ‘proximal’ muscles, like the hips and the shoulders, are the first to be affected. Often the earliest indication that a child may have DMD, is their difficulty in getting up from the floor, walking or running. Gradually, the child’s other muscles will begin to weaken as well. Without dystrophin, muscles become inflamed over time. As the muscles try to repair themselves, fatty or fibrous material builds up in the muscle and causes them to stop working altogether. This is because fibrosis causes the muscles to become rigid and hard. Some children with DMD also have learning and behavioural difficulties This is because dystrophin is also found in the brain, although we are not yet sure of its purpose there. For more information about the different stages of DMD, please click here. Advances in research and knowledge of the disease are increasing life expectancy. Now, more and more young adults with DMD are leading full lives – going to university, having relationships and living independently. However, men and women with DMD do have a reduced life expectancy. Most adults with DMD will not live beyond their 40s.