High Quality Content by WIKIPEDIA articles! Becker muscular dystrophy is an X-linked recessive inherited disorder characterized by slowly progressive muscle weakness of the legs and pelvis. It is a type of dystrophinopathy, which includes a spectrum of muscle diseases in which there is insufficient dystrophin produced in the muscle cells, resulting in instability in the structure of muscle cell membrane. This is caused by mutations in the dystrophin gene, which encodes the protein dystrophin. Becker muscular dystrophy is related to Duchenne muscular dystrophy in that both result from a mutation in the dystrophin gene, but in Duchenne muscular dystrophy no functional dystrophin is produced making DMD much more severe than BMD. Both Duchenne and Becker muscular dystrophy have traditionally been called "X-linked" recessive diseases, but in view of modern molecular biology and identification of the dystrophin gene, it might be more appropriate to say they are X-chromosome recessive diseases.