muscular dystrophy (md) is a group of disorders that involve muscle weakness and loss of muscle tissue. duchenne muscular dystrophy (dmd) is a rapidly-worsening form of md. dmd is caused by a defect in the dystrophin gene. the dystrophin protein is a vital part of a protein complex involved in muscle support and structure. dmd is much more common in boys than in girls ( about 1/3500 boys have dmd, girls rarely have dmd). which statements about dmd are accurate? check all that apply.