Age 3-5: diagnosis
Symptoms of Duchenne muscular dystrophy typically appear in the first few years of life. Infants may struggle to sit or stand up independently, and may start to walk at a later age. Children with Duchenne often have trouble keeping up with their peers. They have progressive muscle weakness of the legs and pelvic muscles. Their calves begin to enlarge, causing them to waddle when walking and making it difficult to climb stairs. Diagnosis is usually made by looking at raised creatine kinase enzymes in the blood. A muscle biopsy can also be done to look for abnormal levels of dystrophin, to confirm a diagnosis.