Becker Muscular Dystrophy (BMD)

Age of onset

2 to 16 years

Symptoms

Similar to Duchenne MD, but less severe. They include general muscle weakness, especially in the upper leg and arms, and pelvic muscles. Calf muscles are generally hypertrophic (bigger than usual). Heart problems are also possible

Rate of Progression

Slower than Duchenne MD

Inheritance

X-linked recessive. BMD primarily affects young males, who inherit the condition through their mothers. Women can be carriers but usually exhibit no symptoms, because the dystrophin gene is located on the X chromosome – of which women have 2 copies – and one functioning copy of the dystrophin gene is generally sufficient for normal muscle function.