Duchenne Muscular Dystrophy

Symptoms

What are the symptoms of Duchenne muscular dystrophy

The average age of a Duchenne diagnosis is around 4 years. Many times there will be delays in early developmental milestones such as sitting, walking, and/or talking. Speech delay and the inability to keep up with peers will often be the first signs of the disorder. Weakness related to Duchenne muscular dystrophy (DMD) selectively affects the limb muscles close to the trunk before the ones far from it; the legs are affected before the arms. As the disease progresses, muscle weakness and atrophy spread to affect the lower legs, forearms, neck and trunk.

Toddlers and young children may seem clumsy, fall often and may have abnormal enlargement of the calves. Parents may note that children have trouble climbing stairs, getting up from the floor, or running. By school age, children may walk on their toes or the balls of their feet with a slightly waddling gait and fall frequently. To try to keep their balance, they may stick out their bellies and pull back their shoulders. Children also have difficulty raising their arms.

Many children with DMD begin using a wheelchair by the age of 12. In the teen years, activities involving the arms, legs, or trunk may require assistance or mechanical support. By the late teens, DMD may also be characterized by additional, potentially life-threatening complications, including weakness and deterioration of the heart muscle (cardiomyopathy).

How is it diagnosed

A diagnosis of DMD is made based upon a thorough clinical evaluation, a detailed patient history, and a variety of specialized tests, including molecular genetic tests. If the genetic tests are not informative, surgical removal and microscopic examination (biopsy) of the affected muscle tissue may reveal characteristic changes to muscle fibers. Specialized blood tests (e.g., creatine kinase) that evaluate the presence and levels of certain proteins in muscle are also used.

Genetic testing involves analyzing the DNA of any cells (usually blood cells are used) to see whether there is a mutation in the dystrophin gene, and if so, exactly where it occurs. Samples of blood or muscles cells may be tested. These techniques can also be used to diagnosis DMD before birth (prenatally).

Blood tests may reveal elevated levels of the creatine kinase (CK), an enzyme that is found in abnormally high levels when muscle is damaged. The detection of elevated CK levels (usually in the thousands or ten thousands range) can confirm that muscle is damaged or inflamed, but cannot confirm a diagnosis of DMD.

Medications

Duchenne muscular dystrophy

The following specialty medications are available at Accredo, a specialty pharmacy for Acute Hepatic Porphyria .