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Muscular dystrophy (MD) is a group of more than 30 genetic diseases. They cause weakness of the muscles. Over time, the weakness gets worse and can cause trouble walking and doing daily activities. Some types of MD can also affect other organs.

There are many different types of MD. Some of the more common types include:

• Duchenne muscular dystrophy, which is the most common childhood form. It is severe and affects boys more often than girls. The symptoms usually start between ages 3 and 6.
• Becker muscular dystrophy, which is similar to Duchenne but is less severe and gets worse more slowly. It often starts in the teenage years.
• Congenital muscular dystrophies, which are present at birth or before age 2. They can be mild or severe.
• Facioscapulohumeral muscular dystrophy, which often starts in the teenage years. At first, it affects the muscles of the face, shoulders, and upper arms.

Each of the types of MD can be different in many ways, such as:

• Who is more likely to get them
• Which muscles they affect
• When they appear, such as in infancy, childhood, middle age, or later
• What the symptoms are
• How serious the symptoms are
• How quickly they get worse
• Whether they run in families
• Whether they affect other organs

Even within the same type of MD, people can have different symptoms.

MD is genetic, meaning that it caused by a change in one or more genes. Gene changes are also called gene variants or mutations. The gene changes in MD affect proteins that strengthen and protect muscles.

There are different gene changes that cause each type of MD. And sometimes people who have the same type of MD can have different gene changes.

Muscular dystrophy can run in families, or you can be the first in your family to have a muscular dystrophy.

To find out if you or your child has MD, your health care provider may use:

• A medical and family history
• A physical exam
• Blood and urine tests, including genetic tests and tests for certain enzymes that may be released by damaged muscles
• Muscle biopsies
• Electromyography and nerve conduction studies to find out if muscles are responding the right way to nerve signals
• Heart testing, such as an electrocardiogram (EKG), since some types of MD can cause heart problems
• Exercise tests to measure muscle strength and breathing and detect any increased rates of certain chemicals following exercise
• Imaging tests such as an MRI to look at muscle quality and bulk and measure fatty replacement of muscle tissue

There is no cure for muscular dystrophy. Treatment can help with the symptoms and prevent complications. It usually includes a combination of therapies, such as:

• Physical therapy to help keep muscles flexible and strong
• Occupational therapy to relearn lost motor skills and learn ways to work around weakened muscles
• Respiratory care, such as breathing exercises, oxygen therapy, and ventilators
• Speech therapy to help with speech and swallowing problems
• Assistive devices, such as wheelchairs, splints and braces, and walkers
• Medicines to help delay damage to muscles or minimize the symptoms of MD
• Surgery to treat some of the conditions associated with MD, such as heart problems, scoliosis, and cataracts

NIH: National Institute of Neurological Disorders and Stroke