Pediatrics Rehabilitation Exam 2 Practice

Duchenne muscular dystrophy occurs because no functional dystrophin protein is produced. Dystrophin normally anchors the muscle cell membrane to the surrounding matrix, protecting the membrane during contraction. Without it, the sarcolemma becomes fragile, membranes tear with use, calcium influx triggers degenerative processes, and muscle fibers progressively die and are replaced by fat and connective tissue. This absence of dystrophin explains the early, severe proximal weakness seen in Duchenne. By contrast, producing dystrophin but defective would lead to Becker muscular dystrophy, and producing dystrophin normally would not cause the disease.