Duchenne dystrophy (DMD) may be a severe sort of dystrophy . Muscle weakness usually begins round the age of 4 in boys and worsens quickly. Muscle loss typically occurs first within the thighs and pelvis followed by the arms. this will end in trouble standing up. Most are unable to steer by the age of 12. Affected muscles may look larger thanks to increased fat content. Scoliosis is additionally common. Some may have intellectual disability. Females with one copy of the defective gene may show mild symptoms. The disorder is X-linked recessive. About two thirds of cases are inherited from an individual's mother, while one third of cases are thanks to a replacement mutation. it's caused by a mutation within the gene for the protein dystrophin. Dystrophin is vital to take care of the muscle fiber's cell wall . Genetic testing can often make the diagnosis at birth. Those affected even have a high level of creatine kinase in their blood.