Muscular dystrophies are a group of diseases caused by defects in a person’s genes. Over time, this muscle weakness decreases mobility and makes the tasks of daily living difficult. There are many muscular dystrophies and the Centers for Disease Control and Prevention (CDC) studies the major types.
Different types of muscular dystrophy affect specific groups of muscles, have a specific age when signs and symptoms are first seen, vary in how severe they can be, and are caused by imperfections in different genes. Muscular dystrophy can run in the family, or a person might be the first one in their family to have the condition.
Muscular dystrophy is rare, and there is not a lot of data on how many people are affected by the condition. Much of the information comes from outside the United States. CDC scientists are working to estimate the number of people with each type of muscular dystrophy in the United States. The table below shows what is known about the major types of muscular dystrophy.
How common is this type? In 2007, 349 out of 2.37 million males aged 5-24 years were reported to have DMD or BMD in the United States.1 This means that about 15 out of every 100,000 males ages 5-24 years were affected that year.
In 2009, 233 out of 1.49 million males were reported to have DMD or BMD in Northern England.2 That is, about 16 out of every 100,000 males were affected that year.
Are males or females more likely to be affected? Males
When does muscle weakness typically begin? DMD: Before 5 years BMD: Between 7-12 years
Which muscles usually show weakness first? Upper arms, upper legs
What other parts of the body can be affected? Brain, throat, heart, diaphragm/chest muscles, stomach, intestines, spine
How common is this type? In 2009, 316 out of 2.99 million individuals of all ages were reported to have MMD in Northern England.1 This means that about 11 out of every 100,000 people were affected that year.
Are males or females more likely to be affected? Males and females equally
When does muscle weakness typically begin? Between 10-30 years, but ranges from birth to 70 years
Which muscles usually show weakness first? Face, neck, arms, hands, hips, lower legs
What other parts of the body can be affected? Eyes, throat, heart, stomach, intestines, hormone-producing organs, nerves, skin
7. Moxley RT MG. The Myotonic Dystrophies. In: Rosenberg RN DS, Paulson HL, Ptacek L, Nestler EJ, ed. The Molecular and Genetic Basis of Neurologic and Psychiatric Disease. Philadelphia, PA: Wolters Kluwer; 2008:532-541.
How common is this type? In 2009, 68 out of 2.99 million individuals of all ages were reported to have LGMD in Northern England.1 This means that about 2 out of every 100,000 people were affected that year.
Are males or females more likely to be affected? Males and females equally
When does muscle weakness typically begin? Ranges from early childhood to late adulthood
Which muscles usually show weakness first? Shoulders, hips
What other parts of the body can be affected? Heart, diaphragm/chest muscles, spine
How common is this type? In 2009, 118 out of 2.99 million individuals of all ages were reported to have FSH in Northern England.5 This means that about 4 out of every 100,000 people were affected that year.
Are males or females more likely to be affected? Males and females equally
When does muscle weakness typically begin? By 20 years (average age in the teens)
Which muscles usually show weakness first? Face, shoulders, upper arms, lower legs
What other parts of the body can be affected? Eyes, ears, heart, trunk
How common is this type? In 2009, 68 out of 2.99 million individuals of all ages were reported to have CMD in Northern England.1 This means that about 2 out of every 100,000 people were affected that year.
Are males or females more likely to be affected? Males and females equally
When does muscle weakness typically begin? At birth or in early infancy
Which muscles usually show weakness first? Neck, arms, trunk, legs
What other parts of the body can be affected? Brain, eyes, throat, heart, diaphragm/chest muscles, nerves, spine
How common is this type? In 2009, 10 out of 2.99 million individuals of all ages were reported to have DD in Northern England.1 This means less than 1 out of every 100,000 people were affected that year.
Are males or females more likely to be affected? Males and females equally
When does muscle weakness typically begin? Ranges from late teens to adulthood
Which muscles usually show weakness first? Lower arms, hands, lower legs, feet
What other parts of the body can be affected? Nerves, other muscles, depending on the type of DD
3. Udd B. Distal muscular dystrophies. Handbook of clinical neurology. 2011;101:239-262.
4. Nonaka I. Distal myopathies. Curr. Opin. Neurol. Oct 1999;12(5):493-499.
How common is this type? In 2009, 4 out of 2.99 million individuals of all ages were reported to have OPMD in Northern England.1 This means that less than 1 out of every 100,000 people were affected that year.
Are males or females more likely to be affected? Males and females equally
When does muscle weakness typically begin? After 40 years
Which muscles usually show weakness first? Face (mostly around the eyes), neck, upper arms, upper legs
What other parts of the body can be affected? Throat
5. Brais B. Oculopharyngeal muscular dystrophy. Handbook of clinical neurology. 2011;101:181-192
How common is this type? In 2009, 4 out of 2.99 million individuals of all ages were reported to have EDMD in Northern England.1 This means that less than 1 out of every 100,000 people were affected that year.
Are males or females more likely to be affected? Males
When does muscle weakness typically begin? Between 5-15 years
Which muscles usually show weakness first? Upper arms, lower legs
What other parts of the body can be affected? Heart, spine
For more detailed information on each type of muscular dystrophy, see the summaries provided by Genetics Home Reference from the National Institutes of Health’s U.S. National Library of Medicine:
Early intervention services help children learn important skills. These services can improve a child’s development. Even if the child has not been diagnosed with muscular dystrophy, he or she might be eligible for services. These services are provided through an early intervention system in each state. Through this system, you can ask for an evaluation. In addition, treatment such as physical therapy often does not need to wait for a formal diagnosis.
Having support and community resources can help increase confidence in managing muscular dystrophy, enhance quality of life, and help meet the needs of all family members. It might be helpful for parents of children with muscular dystrophyto talk with one another. One parent might have learned how to address some of the same concerns another parent has. Often, parents of children with special needs can give advice about good resources for these children.
The choices of one family might not be best for another family, so it’s important that parents understand all options and discuss them with their child’s health care providers.
If you have a child with muscular dystrophy, you might:
Find families and events in your area through the Parent Project Muscular Dystrophy, an organization whose work focuses on Duchenne muscular dystrophy.