Understanding muscular dystrophy

Muscular dystrophy is a rare type of neuromuscular disease, a group of conditions affecting certain nerves and muscles.

The “dystrophy” in muscular dystrophy refers to a condition in which tissue, muscle in this case, wastes away. As a result, people with muscular dystrophy have muscle loss and weakness.

What is muscular dystrophy?

Muscular dystrophies include more than 30 diseases, usually inherited in the genes you get from your parents. Traits include:

• Muscle wasting: Muscular dystrophy damages the muscles that control movement. Some forms also affect the heart and the muscles that regulate breathing.
• Childhood onset: Muscular dystrophy often begins in childhood, though some types emerge in adulthood.
• Progressive weakness: Muscular dystrophy is a progressive disease, meaning it worsens over time. Most people eventually lose the ability to walk. Some types of the disease, such as Duchenne, affect the ability to breathe.

Muscular dystrophy has no cure, but treatment can ease symptoms and improve quality of life. Patients with a mild form that develops slowly may have a normal life span. Severe forms may shorten life, but scientists are studying promising new ways to slow the disease.

Who gets muscular dystrophy?

Duchenne and Becker muscular dystrophies affect only males and usually develop by age 12. A woman can be a carrier, meaning she does not have symptoms but may pass these types on to her children. Other types of muscular dystrophy affect either gender, and the age of onset varies.

Among American males ages 5 to 24, roughly one in 7,250 has a diagnosis of Duchenne or Becker muscular dystrophy, according to the Centers for Disease Control and Prevention.

What causes muscular dystrophy?

Muscular dystrophy is caused by changes to genes, the DNA-filled instructions passed down from parents. In muscular dystrophy, certain genetic changes leave muscle fibers vulnerable to damage. Muscular dystrophy can also occur after genes mutate on their own, and this form can also be passed down.

OHSU offers expert genetic testing and counseling for people with muscular dystrophy and their families. In some cases, genetic testing can guide treatment because some medications target specific genetic changes.

Types of muscular dystrophy

Some muscular dystrophies appear in early childhood. Others don’t emerge until the teen years or early adulthood. The most common types are:

• Duchenne: This type is the most common, typically emerging in boys ages 3 to 5. Girls are rarely affected but can be carriers.
• Becker: Although similar to Duchenne, Becker has milder symptoms that progress more slowly. The disease generally begins in late childhood or adolescence.
• Myotonic (Steinert’s disease): This is the most common form of adult-onset muscular dystrophy. People with this condition cannot relax their muscles after contractions.
• Facioscapulohumeral: This type, also called FSHD, typically begins in the teen years. Muscle weakness develops in the face or shoulders.
• Congenital: This group of muscular dystrophies is often apparent at birth or by age 2. These conditions may be linked to difficulty breathing, vision issues or learning problems.
• Limb-girdle: Named for the muscles around the body’s large joints, this type begins in childhood or the teens. It usually affects hip and shoulder muscles first.
• Oculopharyngeal: This type affects the eyelid and throat muscles first. It can also affect muscles in the face and limbs.

Symptoms of muscular dystrophy

The main symptom is muscle weakness. Other symptoms include:

• Frequent falls or trouble running and jumping
• Waddling or walking on the toes
• Large calf muscles
• Learning disabilities
• Weakness in the face, neck, arms, hands, hips and lower legs

Diagnosing muscular dystrophy

Most often, patients are referred to our center by their primary care doctor. Your OHSU team will seek a fast diagnosis so you can start treatment.

You will meet with multiple specialists, who will work together to complete your testing, often that day. We will also talk with you about your health history and symptoms. We will do a physical exam and screening tests. These may include:

EMG: You can expect to take an electromyography test, which takes about 30 minutes. An EMG measures electrical activities to tell doctors if there’s a problem with messages between your nerves and muscles.

Nerve conduction studies: These tests measure how quickly electrical signals travel along nerves. We use small electrodes on the skin to stimulate the nerves, then measure their response.

Muscle biopsy: We collect a tiny sample of muscle tissue and look at it under a microscope. Our pathologists, doctors who specialize in analyzing tissue, can look for signs of muscular dystrophy. Our on-site lab returns results in as little as one day.

Blood tests: We may check your blood for an enzyme called creatine kinase. High levels can indicate muscle damage, a sign of muscular dystrophy.

Treatments for muscular dystrophy

The goal of treatment is to slow the progress of muscular dystrophy and relieve symptoms. At OHSU, you’ll work with a team to develop a custom treatment plan. Your options may include medication, rehabilitation, surgery or other approaches, depending on the type and stage of disease.

Support services

OHSU social workers are available at all stages of care to:

• Connect you with resources, such as finding in-home help or support groups.
• Answer questions and provide counseling for you and your loved ones.
• Help with financial questions.
• Help applying for Medicare or disability benefits.

Research and clinical trials

As an academic health center, OHSU strives to make the latest research innovations available to patients. Several of our scientists are making strides in understanding muscular dystrophy:

• Genetic testing: OHSU’s Molecular and Medical Genetics department is part of a CDC-supported effort to improve genetic testing for Duchenne and Becker muscular dystrophy.
• Imaging studies: Our Advanced Imaging Research Center is contributing to studies of MRI imaging to track the progress of Duchenne muscular dystrophy. This research is supported by the National Institutes of Health.
• Disease progression: We are contributors to an international project to create a model of Duchenne muscular dystrophy progression. This model will be used to speed the development and approval of new medications.
• Clinical trials: We also offer access to clinical trials studying new medications and approaches.

Learn more

• Muscular Dystrophy Associations (MDA)
• Muscular Dystrophy, U.S. National Library of Medicine
• Muscular Dystrophy Information Page, National Institute of Neurological Disorders and Stroke
• Muscular Dystrophy, Centers for Disease Control and Prevention
• Muscular Dystrophy, American Academy of Orthopaedic Surgeons