Progressive difficulty walking .......Ability to walk may be lost by age 12
Skeletal deformities .......Chest and back
Muscle deformities .......Contractures of heels, legs
.......Pseudohypertrophy of calf muscles
This disease is a rapidly-worsening form of muscular dystrophy. It is caused by a defective gene for dystrophin. However, it often occurs in people without a known family history of the condition. This disorder is marked by worsening loss of muscle function, which begins in the lower limbs.
Duchenne muscular dystrophy is inherited in what is known as an X-linked recessive pattern. The defective gene is found on the X chromosome. Because women have two X chromosomes, if one contains a normal copy of the gene, that gene will make enough of the protein to prevent symptoms. But boys have an X chromosome from their mother and a Y from father, so if the X chromosome is defective, there is no second X to make up for it and they will develop the disease.
The sons of carrier females each have a 50% chance of having the disease, and the daughters each have a 50% chance of being carriers.
There is no known cure for this disease. Treatment is aimed at control of symptoms to maximize the quality of life. Gene therapy may become available in the future.
Activity is encouraged. Inactivity can worsen the muscle disease. Physical therapy may be helpful to maintain muscle strength and function. Orthopedic appliances such as braces and wheelchairs, may improve mobility and the ability for self-care.