What Is Muscular Dystrophy? Facts and Statistics
Muscular Dystrophy Statistics
Muscular dystrophy (MD) disease in the U.S. affects 1 in 50 million girls and 1 in 5,600 to 7,000 males from ages 5 to 24. In the world, 1 in 3,500 males has MD. There are nine different types of MD:
- Myotonic: Most common MD in both men and women.
- Duchene: Most common in children from 2-6 years of age (life expectancy of 20 years).
- Becker: Symptoms tend to appear more slowly between 2-16 years old, but it can appear at age 20 (males may live to adulthood).
- Limb-girdle: Occurs in men and women from teenagers to adults. Walking is difficult or impossible by age 20, underlined by progressive weakness in the hips, then shoulders, arms.
- Facioscapulohumeral: Appears in the teens (men and women) and affects the face, shoulders and upper arm bone, but 50% of patients usually can still walk into adulthood.
- Congenital: Present at birth and progresses slowly for men and women.
- Oculopharyngeal. Affects mainly the eye and throat and is most prevalent in men and women ages 40-60.
- Emery-Dreifuss: Appears in the teens, primarily males. Life-threatening heart problems are common.
The disease is most prevalent in males. Symptoms may progress slowly, but some experience severe muscle weakness, with wasting and dying by the late teens.
General Information About Muscular Dystrophy
MD is a group of genetic diseases. They cause progressive muscle weakness that will sometimes appear early in life, and at other times, it will progress more slowly. Various muscle groups can be affected, depending on the type of MD.
The most common MD form is Duchenne, which appears from ages 3-6 for boys and progresses quickly. While Becker MD has similar symptoms, it does not appear until the mid-teens or 20s and progresses more slowly.
Common symptoms include:
- Waddling way of walking
- Fast or slow progressive muscle weakness and wasting
- Difficulty climbing stairs
- Difficulty in rising from a lying or sitting position
- Falling repeatedly
- Muscle wasting of the thigh muscles
- Spine curvature
- Abnormal enlargement of the calves
- Breathing trouble or trouble with swallowing
- Limbs drawing inward and they may end up in a fixed position
- Heart enlargement
- Learning disabilities
- Delayed growth
There are several possible complications, including:
- Difficulty with walking - wheelchair use is common
- Trouble using arms - daily activities may be difficult
- Muscle contractures also limit mobility
- Breathing difficulties when breathing muscles are affected
- Curved spine (scoliosis)
- Heart problems
- Problems swallowing that may cause nutritional problems or aspiration may occur
Causes of Muscular Dystrophy
Simply put, defective genes cause MD. It can be inherited in individuals with a family history of MD, or it can arise from a spontaneous mutation. Researchers have identified the genes that are defective for each type of MD. Often, a protein is missing that keeps muscle cells intact as is the case in Duchenne's MD.
Duchenne vs. Becker Muscular Dystrophy
When I was young there was a boy in a wheelchair in some of my classes and in my Sunday school class. When I was in 6th grade this boy’s mother brought him into the Sunday school class. I knew nothing about his muscle dystrophy, but I do remember looking at his mother and noticing how tired she looked. She had dark circles under her eyes. I am surprised I noticed these things at that age, but I remember it clearly. I never got to know this boy as we had a huge number of classmates in high school. This poor boy died in my senior year. We had a picture of him in the first part of our yearbook. It was truly very sad.
The diagnosis of MD is usually dependent on the results of a muscle biopsy. The muscle biopsy takes a small piece of muscle to examine using a microscope. Dead muscle tissue or abnormally large fibers are indicators of MD.
A blood test will show the creatine phosphokinase enzyme (CPk3) is leaking from muscle cells, resulting in high levels of the enzyme in the blood. This does not totally confirm this disease, but it is a strong indicator.
An electromyography and nerve conduction studies can also be done to detect the presence, location and extent of this disease causing muscle tissue damage.
A physical exam will be completed to determine the muscular dystrophy type as different types of this disease affect different muscle groups. AddItionally, a chest X-ray, an echocardiogram, a CT scan or a MRI scan will be completed. Quality of life may be assessed as well.
Genetic testing may also be performed to confirm the diagnosis.
Muscular Dystrophies in Adolescents: Mayo Clinic
Muscular Dystrophy Treatment
Unfortunately, there is no cure for this disease. Sometimes, physical therapy may help prevent some muscles from permanently contracting around the joints, for example, preventing curvature of the spine.
Sometimes, surgery is necessary to release very tight, painful muscles. Breathing exercises can be useful to delay any weakening of respiratory muscles.
Prednisone (a corticosteroid) may be ordered for temporary relief of muscle weakness. It also helps prevent muscle damage. For Emery-Dreifuss MD, heart damage may be treated with medications or the patient may need a pacemaker.
Gene therapy is being studied by researchers. This would enable the patient’s muscles to produce dystrophin, strengthening them. More studies are constantly being conducted to better understand and treat this disease.
The prognosis for MD varies according to the type of MD. Some cases are very slow to progress while some cases progress very rapidly and from an early age. Although in some cases, patients can live well into adulthood, life expectancy is often capped at around 20 years of age. Because no cure is available at this time, rigorous physical therapy, exercise, and some medications may be able to slow the progression or relieve the symptoms.
- Cedars Sinai. (2019). Muscular Dystrophy.
- NICHD: NIH. (2016). Muscular Dystrophy Condition Information: How may people are affected by or are at risk of muscular dystrophy?
- NIH. (2019). Muscular Dystrophy Information Page.
- WebMD. Reviewed by B. Nazario, MD. (25 June 2020). Understanding muscular dystrophy basics.
This content is for informational purposes only and does not substitute for formal and individualized diagnosis, prognosis, treatment, prescription, and/or dietary advice from a licensed medical professional. Do not stop or alter your current course of treatment. If pregnant or nursing, consult with a qualified provider on an individual basis. Seek immediate help if you are experiencing a medical emergency.
© 2020 Pamela Oglesby