Becker Muscular Dystrophy (BMD) in Children
Muscular dystrophy (MD) is an inherited (genetic) disorder of the muscles. It is called a neuromuscular disease. There are several types. Becker muscular dystrophy (BMD) is a rare type. It has milder symptoms than Duchenne muscular dystrophy (DMD), which is more common. BMD causes weakness of skeletal muscles, breathing muscles, and the heart muscle. Over time, the muscle fibers break down.
BMD is a genetic disease. This means it passes from parents to children. It is caused by a faulty gene on the X chromosome. It mostly affects boys. Girls are only carriers and usually don’t have symptoms.
People normally have 23 pairs of chromosomes in each cell of their body. The 23rd pair controls a person’s gender. This pair is 2 X chromosomes for females. The pair is 1 X and 1 Y chromosome for males.
The faulty BMD gene is an X-linked
recessive gene. This means the gene needs to be on each X chromosome for symptoms of the
disease to occur in girls. A girl would need 2 copies--1 copy on each X chromosome. If
she has only 1 copy on 1 X chromosome, she is a carrier of the disease but will not have
symptoms. Boys only have one X chromosome. If their X chromosome has a faulty gene, they
will have symptoms.
A child is more at risk for BMD if he or she has a family member with the disease. Girls are rarely affected by this type of muscular dystrophy.
Symptoms usually start during teen or early adult years. They can include:
- Muscle cramping and feeling weak when exercising
- Trouble walking, running, jumping, climbing stairs
- Falling often
- Muscle pain
- Enlarged calves
- Walking on tips of toes
- Weakness in arms and shoulders
The symptoms of Becker muscular dystrophy can be like other health conditions. Make sure your child sees his or her healthcare provider for a diagnosis.
The healthcare provider will ask about your child’s symptoms and health history. He or she may also ask about your family’s health history to find out if other family members have had muscular dystrophy. He or she will give your child a physical exam. Your child may also have tests, such as:
Blood tests. These may include genetic blood tests.
Electromyogram (EMG). This is a test to check if muscle
weakness is a result of destroyed muscle tissue or nerve damage.
Muscle biopsy. A small sample of muscle tissue is taken
and looked at under a microscope.
Electrocardiogram (ECG). This is a test that records the
electrical activity of the heart. It shows abnormal rhythms (arrhythmias) and detects
heart muscle damage.
Echocardiogram. This is an ultrasound test of the heart
muscle. It shows a picture of how strong the heart muscle is pumping.
Treatment will depend on your child’s symptoms, age, and general health. It will also depend on how severe the condition is.
There is no known cure for BMD, or treatment to stop the muscles from weakening. The goal of treatment is to keep muscles as strong as possible to allow a child to function independently.
Treatment choices include:
- Physical therapy to strengthen muscle and help prevent muscle contractures
- Braces and splints
- The use of steroid medicines, although
it is uncertain if they help
- Surgery to treat contractures
- Medicine for heart disease
- Medicines from clinical research trials
- Wheelchair use
- Nutritional counseling
- Psychological counseling
Talk with your child’s healthcare providers about the risks, benefits, and possible side effects of all treatments.
Children with BMD may have additional health problems, such as:
- Heart muscle weakening and not pumping
blood well (dilated cardiomyopathy)
- Breathing and lung problems
- Scoliosis, a sideways curving of the
back bones (vertebrae)
- Diet, nutrition, and digestive
- Trouble focusing, learning, or
- Complications from anesthesia, for which special care is
Your healthcare provider may advise
genetic counseling. You can discuss with a counselor the risk for BMD in a future
BMD is a condition that gets worse
over time (progressive). It needs life-long management. Walking and sitting often become
more difficult as a child grows. In time your child will need a wheelchair in his or her
late teen years or early 20s. This is because the leg muscles become too weak to work.
In some cases, a child may need a wheelchair earlier.
Your child will also need a heart
imaging test every 1 to 2 years. This may be a heart echocardiogram or a magnetic
resonance imaging (MRI) scan. These tests look at the function and health of the heart.
A child with BMD will need special care during surgery to prevent problems from
People with BMD usually live until their 40s. Problems from cardiomyopathy are a common cause of death.
A healthcare team will work with your family to improve your child's function and to give support as you learn to care for your child's needs.
You can contact the Muscular Dystrophy Association (www.mda.org) for support, resources, and help.
When to Call a Healthcare Provider
Call the healthcare provider if your child has:
- Symptoms that don’t get better, or get worse
- New symptoms
- Becker muscular dystrophy (BMD) is a rare inherited disorder of the muscles.
- BMD causes weakness of skeletal muscles, breathing muscles, and the heart muscle. Over time, the muscles may become too tight and pull together painfully.
- A child is more at risk for BMD if he or she has a family member with the disease. Girls are rarely affected.
- There is no known cure for BMD, or treatment to stop the muscles from weakening. The goal of treatment is to keep muscles as strong as possible to allow a child to function independently.
- Your healthcare provider may advise
genetic counseling. You can discuss with a counselor the risk of BMD in a future
Tips to help you get the most from a visit to your child’s healthcare provider:
- Know the reason for the visit and what you want to happen.
- Before your visit, write down questions you want answered.
- At the visit, write down the name of a new diagnosis, and any new medicines, treatments, or tests. Also write down any new instructions your provider gives you for your child.
- Know why a new medicine or treatment is prescribed and how it will help your child. Also know what the side effects are.
- Ask if your child’s condition can be treated in other ways.
- Know why a test or procedure is recommended and what the results could mean.
- Know what to expect if your child does not take the medicine or have the test or procedure.
- If your child has a follow-up appointment, write down the date, time, and purpose for that visit.
- Know how you can contact your child’s provider after office hours. This is important if your child becomes ill and you have questions or need advice.