Becker Muscular Dystrophy (BMD): Causes and Treatments

Muscular dystrophy refers to a group of more than 30 inherited (genetic) diseases that cause muscle weakness. These conditions are a type of myopathy, a disease of the skeletal muscles. Over time, muscles shrink and become weaker, affecting your ability to walk and perform daily activities like brushing your teeth. The disease also can affect your heart and lungs.

Some forms of muscular dystrophy are apparent at birth or develop during childhood. Some forms develop later during adulthood. Currently, there isn’t a cure.

Becker Muscular Dystrophy (BMD)

How common is muscular dystrophy?

Muscular dystrophy is a rare condition.

Who might get muscular dystrophy?

Muscular dystrophy often runs in families. A child who has a parent with muscular dystrophy may inherit a mutated (changed) gene that causes muscular dystrophy. Some people have the mutated gene but don’t have muscular dystrophy. These healthy adults (carriers) can pass the mutated gene to their child, who may develop the disease.

What are the types of muscular dystrophy?

There are more than 30 different types of muscular dystrophy. Some of the more common forms include:

Duchenne muscular dystrophy (DMD): This condition tends to affect boys between the ages of 2 to 5, but girls can get it, too. You may notice that your toddler has a hard time running, walking or jumping. As the disease progresses, it can affect a child’s heart and lungs. DMD is the most common form of muscular dystrophy. It affects approximately six out of 100,000 children in North America and Europe.
Becker muscular dystrophy (BMD): BMD is the second most common muscular dystrophy. Symptoms of BMD can appear anytime between age 5 and 60, but typically come on during the teen years. Males are more likely to get BMD. The disease affects the hip, thigh and shoulder muscles, and eventually the heart. Approximately one out of 18,000 to 30,000 U.S. boys develop BMD.
Facioscapulohumeral muscular dystrophy (FSHD): FSHD is the third most common muscular dystrophy. The disease affects muscles in the face, shoulder blades and upper arms. Symptoms tend to appear before age 20. About four out of 100,000 people in the U.S. have this form.
Congenital muscular dystrophies (CMD): Congenital conditions like CMD are present at birth. An infant may have weak muscles, a curved spine and joints that are too stiff or loose. Children with CMD may have learning disabilities, seizures and vision problems.
Emery-Dreiffus muscular dystrophy (EDMD): This condition tends to affect children. Symptoms, such as weak shoulders, upper arms and calf muscles, appear by age 10. EDMD also affects the heart.
Limb-girdle muscular dystrophy (LGMD): This disease affects the muscles closest to the body including the shoulders and hips. It affects people of all ages. Approximately two out of 100,000 people in the U.S. have LGMD.
Myotonic dystrophy: People with myotonia have trouble relaxing their muscles. For instance, you might find it difficult to let go of a loved one’s hand. The disease also affects the heart and lungs. This condition tends to affect adults of European descent and occurs in approximately 10 out of 100,000 people.
Oculopharyngeal muscular dystrophy (OPMD): This rare form of muscular dystrophy weakens muscles in the eyelids and throat. Symptoms, such as droopy eyelids (ptosis) and difficulty swallowing (dysphagia), often appear between the 40s and 60s. About one in 100,000 people have OPMD.

SYMPTOMS AND CAUSES

What causes muscular dystrophy?

Genetic mutations, or changes, cause most forms of muscular dystrophy. One or both parents may pass a faulty gene to their child even if the parent doesn’t have the condition. Rarely, a person develops muscular dystrophy spontaneously, meaning there’s no known cause.

What are the symptoms of muscular dystrophy?

Muscle weakness is the primary symptom of muscular dystrophy. Depending on the type, the disease affects different muscles and parts of the body. Other signs of muscular dystrophy include:

Enlarged calf muscles.
Difficulty walking or running.
Unusual walking gait (like waddling).
Trouble swallowing.
Heart problems, such as arrhythmia and heart failure (cardiomyopathy).
Learning disabilities.
Stiff or loose joints.
Muscle pain.
Curved spine (scoliosis).
Breathing problems.

DIAGNOSIS AND TESTS

How is muscular dystrophy diagnosed?

If your healthcare provider suspects muscular dystrophy, you or your child may undergo one or more of these diagnostic tests:

An enzyme and protein blood test checks for elevated levels of an enzyme called creatine kinase. High levels can indicate muscle damage caused by muscular dystrophy.
Electromyography (EMG) measures the electrical activity of muscles and nerves.
A muscle biopsy looks for cell changes in muscle tissue.
Genetic tests identify gene mutations linked to muscular dystrophy.

MANAGEMENT AND TREATMENT

How is muscular dystrophy managed or treated?

Researchers are still looking for a way to cure muscular dystrophy. Disease symptoms get worse over time, but these treatments can help:

Physical and occupational therapies strengthen and stretch muscles. These therapies can help you maintain function and range of motion.
Speech therapy helps those who have problems swallowing.
Corticosteroids, such as prednisone and deflazacort, may slow disease progression.
Surgery relieves tension on contracted muscles and corrects spine curvature (scoliosis).
Heart assist devices, such as pacemakers, treat heart rhythm problems and heart failure.
Medical devices, such as walkers and wheelchairs, can improve mobility and prevent falls.
Respiratory care, such as cough-assist devices and respirators, aid breathing.

What are the complications of muscular dystrophy?

Muscular dystrophy affects your muscles, heart and lungs. As the disease progresses, you may be more prone to:

Heart problems, such as arrhythmias and heart failure.
Respiratory infections, including pneumonia.
Breathing problems.
Choking.

How does muscular dystrophy affect pregnancy?

Women with muscular dystrophy can have healthy pregnancies. Because muscular dystrophy is inherited, you may want to talk to a genetic counselor before conceiving. During pregnancy, your healthcare provider will closely monitor your health to help you avoid these complications:

Increased muscle weakness and limited mobility due to weight gain.
Breathing problems due to added pressure on your lungs.
Heart strain.
Miscarriage (loss of pregnancy before the baby fully develops).
Premature labor before the 37th week of pregnancy.
Low birth weight baby, weighing less than 5 pounds, 8 ounces.

PREVENTION

How can I prevent muscular dystrophy?

Unfortunately, there isn’t anything you can do to prevent getting muscular dystrophy. If you have the disease, these steps can help you enjoy a better quality of life:

Eat a healthy diet to prevent malnutrition.
Drink lots of water to avoid dehydration and constipation.
Exercise as much as possible.
Maintain a healthy weight to prevent obesity.
Quit smoking to protect your lungs and heart.
Get flu and pneumonia vaccines.

OUTLOOK / PROGNOSIS

What is the prognosis (outlook) for people with muscular dystrophy?

Muscular dystrophy is a progressive disease. Symptoms get worse over time. Physical and occupational therapy, and medical devices like walkers, can help you maintain mobility and independence for as long as possible. Medical specialists provide therapies and can offer recommendations to protect your heart and lungs.

LIVING WITH

When should I call the doctor?

You should call your healthcare provider if you have muscular dystrophy and you experience:

Signs of a respiratory infection.
Difficulty swallowing or choking.
Heart palpitations or chest pain.
Muscle pain.

What questions should I ask my doctor?

If you have muscular dystrophy, you may want to ask your healthcare provider:

Are my children at risk for muscular dystrophy?
What steps can I take to prevent passing on the muscular dystrophy gene to my children?
Should I get genetic testing?
How will muscular dystrophy affect my quality of life?
Will having muscular dystrophy shorten my life?
What steps can I take to slow the progression of the disease?
What changes can I expect as the disease progresses?
If a loved one has muscular dystrophy, should I get genetic testing to see if I carry the gene mutation?
Should I look out for signs of complications?

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