Diagnostic Test

Electromyography (EMG)

Genetic tests

Muscle biopsy

Serum CPK

Congestive heart failure or irregular heart rhythm
Deformities of the chest and back (scoliosis)
Enlarged muscles of the calves, buttocks, and shoulders (around age 4 or 5). These muscles are eventually replaced by fat and connective tissue.
Loss of muscle mass (wasting)
Muscle contractures in the heels, legs
Muscle deformities
Respiratory disorders, including pneumonia and poor swallowing, with food or fluid passing into the lungs (in late stages of the disease)