Duchenne muscular dystrophy is a severe X-linked recessive type of muscular dystrophy which mostly affects boys with a muscle weakness that usually begins around the age of four and can progress quickly. They then have difficulty standing and most are not able to walk by the age of 12.
The muscle weakness is initially in the proximal muscles of the pelvis and thigh with the arms being affected next. The first signs of Duchenne muscular dystrophy start around ages 4 to 5 years and usually manifest as subtle gait abnormalities often with an increased cadence and decreased stride length. Some may toe walk. Falling over more frequently than their peers may also be noticeable. Following these initial signs walking becomes increasingly difficult due to the increasing muscle weakness.
A characteristic sign of Duchenne muscular dystrophy that develops as the pelvic and thigh muscle weakness progresses is a difficultly standing up from lying or sitting position – this is called a positive Gowers’ sign. When the child attempts to arise from lying on their front, they compensate for pelvic muscle weakness by the use of their upper extremities. The first rise to standing using the arms and knees, and then ‘walking’ their hands up the legs to be able to stand upright