The first symptoms of Duchenne muscular dystrophy are usually noticed in early childhood. Delays in developmental milestones, such as sitting and standing, are common. The affected child's gait is often a characteristic waddle or toe-walk. He often stumbles, and running is difficult. While parents notice these symptoms retrospectively, and may notice them at the time, muscular dystrophy often is not suspected until additional signs are apparent. By the age of four to five years, it is difficult for the child to climb stairs or rise from a sitting position on the floor. It is around this time that the diagnosis is usually made. A particular method, called the Gower sign is used by the child to raise himself from sitting on the floor. These motor problems are caused by weakness in large muscles close to the center of the body (proximal).
Although some muscles, such as the calves, appear to be large and defined, the muscle is actually atrophied and weak. It appears large because deposits of fatty, fibrous tissue are replacing muscle tissue. Enlarged calves are a characteristic sign of Duchenne muscular dystrophy, and are said have pseudohypertrophy. "Pseudo" means false, "hyper" is excessive, and " trophy" is growth or nourishment. Other muscles may also have pseudohypertophy. These muscles feel firm if massaged.
The weakness begins at the center of the body (the pelvis) and progresses outward from the hips and shoulders to the large muscles of the legs, lower trunk, and arms. The weakness is symmetrical; i.e. both sides of the body are equally weak. Early signs of weakness, such as stumbling and difficulty climbing, progress to the point that the affected boy is unable to walk. Boys with Duchenne muscular dystrophy usually require wheelchairs by the age of 12 years. Eventually the muscles that support the neck are affected. The muscles of the digestive tract are affected in some males in the later stages of the disease. Contractures and scoliosis develop. Some boys also have learning disabilities or mild mental retardation.
Michelle Q. Bosworth MS, CGC, The Gale Group Inc., Gale, Detroit,