Becker muscular dystrophy (often called Becker MD or BMD) is a form of muscular dystrophy, a genetic disorder that gradually makes the body's muscles weaker and smaller. It causes less severe problems than the most common type, Duchenne muscular dystrophy.
Becker MD symptoms can range from mild to almost as severe as the symptoms of Duchenne MD.
A child with Becker MD may start to walk later than most kids do. But the disease rarely causes health problems until a child has muscle weakness in the hips and pelvis. This usually happens when kids are 10–13 years old. Walking problems are usually noticed around age 15–16.
A child with Becker MD may:
Becker MD affects the muscles of the hips, pelvis, thighs, and shoulders, as well as the heart. Changes in the heart muscle may happen faster than in other muscles. Children who first show symptoms of Becker MD at younger ages are more likely to have heart problems than kids whose symptoms start later.
Becker MD is progressive, meaning problems get worse with age. Symptoms gets worse slowly compared with Duchenne MD. Breathing muscles tend to stay strong enough that a ventilator or other mechanical breathing help isn't needed.
In Becker MD, muscles weaken because dystrophin (dis-TRO-fin), a protein made by muscle cells, doesn't work as it should. A change in the dystrophin gene makes the protein too short. The flawed dystrophin puts muscle cells at risk for damage with normal use.
Usually, the body will repair or replace damaged muscle cells. But in Becker MD, the cells die instead. After the muscle cells die, they are replaced by fat and scar tissue.
Among children with the Becker MD gene, boys are most affected with weakness in their arm and leg movements. That's because the dystrophin gene is on the X chromosome. Boys have only one X chromosome, but girls have two. So girls almost always have a second copy of the gene that can make the full, working dystrophin protein. Girls can be carriers and are at risk of passing this on to their children. Girls can also have symptoms, but in general they are less severe than in boys.
Both boys and girls with a Becker MD gene can have heart problems.
Most children with a faulty dystrophin gene get it from the mother, who may carry the faulty gene without knowing it. In some children, the faulty gene is a new genetic change called a mutation or variation.
Doctors often diagnose muscular dystrophy based on the child's family history, symptoms, and an exam.
These tests confirm the diagnosis and determine the type of muscular dystrophy:
There's no cure yet for Becker MD. Treatment is a combination of:
A child with Becker MD usually is cared for by a team of doctors and other experts from several pediatric specialties.
Kids with Becker MD can live long, active lives, and research to improve treatment is underway.
Some people with Becker MD begin using a wheelchair in their twenties. But many over age 50 can walk without help or by using a cane, crutches, or walker.
Becker MD does not affect muscles of the bowel and bladder or sexual function.
Reviewed by: Mena T. Scavina, DO
Date Reviewed: Mar 15, 2018
