Muscular dystrophy is a group of diseases in which muscles become progressively weaker with age. Some versions of this condition progress quickly and are fatal, but benign juvenile muscular dystrophy is much milder. This disease is also known as progressive tardive, or Becker, muscular dystrophy.

Both the more severe version, called Duchenne, and juvenile muscular dystrophy are genetic disorders inherited from the mother. The defective gene is recessive and resides on the X chromosome, so girls who inherit it are usually carriers—they don’t show symptoms. Boys, on the other hand, with only their mother’s X chromosome, do have symptoms. The condition affects about 1 in 30,000 boys.

Because of this genetic glitch, the body does not produce sufficient amounts of a protein called dystrophin. This protein helps muscle cells keep their shape and length; without it, muscles break down. Boys who have Duchenne muscular dystrophy begin experiencing symptoms at about age 2. They start to develop leg weakness, balance problems, and large calf muscles. By late childhood, they often are unable to walk; many sufferers pass away by their late teens or early twenties from pneumonia, lung weakness, or cardiac complications. Boys with benign muscular dystrophy, on the other hand, don’t begin to show the effects of the disease until about age 10 or 11. Their symptoms are less severe and progress more slowly; they usually don’t lose the ability to walk until late adulthood and may retain their mobility.

Unfortunately, there’s no cure for muscular dystrophy. But physical therapy can help maintain the range of motion in joints, anti-inflammatory corticosteroids can help preserve muscle strength, and other prescription medications can help manage muscle spasms and stiffness.

ADDITIONAL FACTS

  1. Becker muscular dystrophy is named after the German physician Peter Emil Becker, who first reported his research on this form of the disease in 1955.
  2. A girl who inherited an abnormal gene from a carrier mom and an abnormal gene from an affected dad would have no normal X chromosome and would be the rare case of an affected female.