Muscular dystrophy is a genetic disorder that causes progressive muscle weakness. It is characterized by defects in muscle proteins and affects skeletal, heart and smooth muscles. The main symptoms are muscle weakness and deterioration over time, leading to difficulties with movement. There are many types of muscular dystrophy but they all involve degeneration of muscle fibers. Currently there is no cure, but treatment focuses on managing symptoms and slowing disease progression through exercise, physical therapy and other means. Researchers are working on developing new treatments such as gene therapy.