What is muscular dystrophy?
Muscular dystrophy is a general name for a group of rare diseases that cause muscle weakness. It is caused by mutations in certain genes. There are more than 30 different types of muscular dystrophy and each affects certain muscles and varies in severity. Some types of muscular dystrophy affect children while others don’t appear until adulthood.
The most common type, called Duchenne muscular dystrophy, usually begins between ages 2 to 5; symptoms progress quickly. About 50 percent of all people with muscular dystrophy have this type. Duchenne muscular dystrophy most often affects boys, though girls can inherit the gene and pass it to their children.
Some other types of muscular dystrophy that can affect children include:
- Becker: This type is related to Duchenne muscular dystrophy, but is less severe.
- Emery-Dreifuss: Most common in boys, this type of muscular dystrophy causes weakness and progressive wasting of the lower leg and upper arm muscles.
- Facioscapulohumeral: This type affects muscles in the face, upper arms, and shoulders.
- Limb-girdle: This is a group of more than 20 inherited conditions that cause progressive muscle loss and weakness.
- Myotonic dystrophy: This is the most common muscular dystrophy in adults, but symptoms can sometimes begin in infancy or childhood.
- Distal: Also called distal myopathy, is a less severe form of muscular dystrophy that usually progresses slowly.
All types of muscular dystrophy get worse over time and can eventually cause the inability to walk. Some types of muscular dystrophy can also cause problems with breathing.
There is no cure for muscular dystrophy, but treatments can prevent complications and help with symptoms.
Muscular Dystrophy | Symptoms & Causes
What are the symptoms of muscular dystrophy?
The most common symptom of all types of muscular dystrophy is muscle weakness that gets worse over time.
Each type of muscular dystrophy has its own specific symptoms:
- frequent falls
- having trouble getting up from a lying or sitting position
- a waddling walk
- difficulty running and jumping
- enlarged calf muscles
- walking on tiptoes
- frequent falls
- muscle cramping
- later onset of symptoms than Duchenne
- trouble with hand movements and extending the fingers
- difficulty climbing stairs and walking
- inability to stand on the heels or hop
- muscle weakness that begins in the upper arms and lower legs
- decreased movement in the spine, knees, elbows, ankles, and back of neck
- elbows locked in a flexed position
- rigid spine
- weakening of the muscles around the eyes and mouth
- slanted shoulders or shoulder blades that looked "winged"
- trouble speaking, swallowing, or chewing
- hearing problems
- a curve in the spine
- weakness around the hips that spreads to the legs, shoulders, and neck
- frequent falls
- a waddle when walking
- rigid spine
- an inability to relax muscles after contracting them
- having a long, thin face and neck
- trouble swallowing
- cataracts, drooping eyelids, and other vision problems
- in infants, trouble swallowing or breathing, lack of reflexes, muscle weakness in the face, and delayed motor skills
What are the causes of muscular dystrophy?
Muscular dystrophy is usually an inherited condition caused by a mutation in one of the genes that affect proteins in the muscles. This mutation causes the protein to be missing or altered so it doesn’t work correctly. Each type of muscular dystrophy is caused by a different mutation.
In some cases, the mutation is not inherited from a parent, but occurs spontaneously. In this case, the mutation can then be passed on future generations.
Muscular Dystrophy | Diagnosis & Treatments
How is muscular dystrophy diagnosed?
The first step in diagnosing muscular dystrophy is a complete exam and medical history. Based on these findings, the clinician may order one of more of the following tests to help diagnose muscular dystrophy and to determine which type the child has.
- blood tests to measure certain enzymes that may indicate muscle damage
- muscle biopsy to check the muscle tissue for muscle disease
- imaging tests, such as magnetic resonance imaging (MRI) or ultrasound to check muscle quality
- neurological tests to rule out other conditions and to test coordination or reflexes
- exercise tests to check muscle strength and check for certain chemicals in the body after exercise
- genetic testing to look for mutations that could signal a specific type of muscular dystrophy
What are the treatments for muscular dystrophy?
There is no treatment that can stop the progression of muscular dystrophy. Instead, available treatments focus on easing symptoms. These can vary from patient to patient, depending on the type of muscular dystrophy a person has and how much it has progressed. These treatments may include:
- physical therapy or occupational therapy to help keep muscles strong and flexible and help patients maintain skills
- speech therapy to improve communication skills in those with muscle weakness in the face
- respiratory therapy if the child has breathing problems
- medications to help increase muscle strength and reduce some of the symptoms of muscular dystrophy, such as muscle spasms or infections
- surgery is sometimes needed to help with the complications of muscular dystrophy, such as implanting a pacemaker for heart problems or surgery to remove cataracts
Expert care for muscular dystrophy
Many of the genes responsible for muscular dystrophies and other neuromuscular disorders were found right here at the Boston Children’s Neuromuscular Center. Today, the researchers who made these discoveries are continuing to learn more and are working to develop treatments. Our team of specialists from neurology, orthopedic surgery, physical therapy, and genetics are experienced in caring for children with muscular dystrophy. We are one of a few sites in the United States funded by the National Institutes of Health (NIH) and various sponsors to conduct clinical studies on muscular dystrophy.