What is Muscular Dystrophy?

Man in a wheelchair reading his laptop

Muscular dystrophies are a group of muscle diseases caused by mutations in a person’s genes. Over time, muscle weakness decreases mobility, making everyday tasks difficult. There are many kinds of muscular dystrophy, each affecting specific muscle groups, with signs and symptoms appearing at different ages, and varying in severity. Muscular dystrophy can run in families, or a person can be the first in their family to have a muscular dystrophy. There may be several different genetic types within each kind of muscular dystrophy, and people with the same kind of muscular dystrophy may experience different symptoms.

Muscular dystrophies are rare, with little data on how many people are affected. The Centers for Disease Control and Prevention (CDC) is working to estimate the number of people with each major kind of muscular dystrophy in the United States.

Learn more about CDC’s research on muscular dystrophy »

Kinds of Muscular Dystrophy

The information on this page is a brief overview of the major kinds of muscular dystrophy.

Duchenne muscular dystrophy (DMD) and Becker muscular dystrophy (BMD) can have the same symptoms and are caused by mutations in the same gene. BMD symptoms can begin later in life and be less severe than DMD. However, because these two kinds are very similar, they are often studied and referred to together (DBMD).

How many people are affected?
About 14 in 100,000 males 5 – 24 years of age

Who is more likely to be affected: males or females?
Males
Learn more about how DBMD is inherited »

When does muscle weakness typically begin?
DMD symptoms usually begin before 5 years of age. In BMD, symptoms usually appear later, even into adulthood.

Which parts of the body show weakness first?
Upper legs and upper arms

What other parts of the body can be affected?
Heart, lungs, throat, stomach, intestines, and spine

How many people are affected?

About 8 in 100,000 people of all ages are affected

 

Who is more likely to be affected: males or females?
Males and females equally

 

When does muscle weakness typically begin?
Usually between 10–30 years of age, but ranges from birth to 70 years old.

 

Which parts of the body show weakness first?
Face, neck, arms, hands, hips, and lower legs

 

What other parts of the body can be affected?
Heart, lungs, stomach, intestines, brain, eyes, and hormone-producing organs

How many people are affected?
About 2 in 100,000 people of all ages

Who is more likely to be affected: males or females?
Males and females equally

When does muscle weakness typically begin?
Childhood or adulthood, depending on the type of LGMD

Which parts of the body show weakness first?
Upper arms, upper legs

What other parts of the body can be affected?
Heart, spine, hips, calves, and trunk

How many people are affected?
About 4 in 100,000 people of all ages

Who is more likely to be affected: males or females?
Males and females equally

When does muscle weakness typically begin?
Young adulthood

Which parts of the body show weakness first?
Face, shoulders, and upper arms

What other parts of the body can be affected?
Eyes, ears, and lower legs

How many people are affected?
About 1 in 100,000 people of all ages

Who is more likely to be affected: males or females?
Males and females equally

When does muscle weakness typically begin?
At birth or in early infancy

Which parts of the body show weakness first?
Neck, upper arms, upper legs, and lungs

What other parts of the body can be affected?
Brain, heart, and spine

How many people are affected?
Less than 1 in 100,000 people

Who is more likely to be affected: males or females?
Males and females equally

When does muscle weakness typically begin?
Adulthood

Which parts of the body show weakness first?
Feet, hands, lower legs and lower arms

What other parts of the body can be affected?
Heart, arms, and legs

How many people are affected?
Less than 1 in 100,000 people

Who is more likely to be affected: males or females?
Males and females equally

When does muscle weakness typically begin?
After 40 years of age

Which parts of the body show weakness first?
Eyes and throat

What other parts of the body can be affected?
Shoulders, upper legs, and hips

How many people are affected?
Less than 1 in 100,000 people of all ages

Who is more likely to be affected: males or females?
Males

When does muscle weakness typically begin?
Childhood

Which parts of the body show weakness first?
Arms, legs, heart, and joints

What other parts of the body can be affected?
Throat, shoulders, and hips

References for this page
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