DMD-associated dilated cardiomyopathy - Genetics Home Reference

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DMD-associated dilated cardiomyopathy

On this page:

• Description
• Genetic changes
• Inheritance
• Diagnosis
• Additional information
• Other names
• Glossary definitions

Reviewed February 2012

What is DMD-associated dilated cardiomyopathy?

DMD-associated dilated cardiomyopathy is a form of heart disease that is caused by mutations in the DMD gene. Dilated cardiomyopathy enlarges and weakens the heart (cardiac) muscle, preventing the heart from pumping blood efficiently. Signs and symptoms of this condition can include an irregular heartbeat (arrhythmia), shortness of breath, extreme tiredness (fatigue), and swelling of the legs and feet. In males with DMD-associated dilated cardiomyopathy, heart problems usually develop early in life and worsen quickly, leading to heart failure in adolescence or early adulthood. In affected females, the condition appears later in life and worsens more slowly.
Dilated cardiomyopathy is a feature of two related conditions that are also caused by mutations in the DMD gene: Duchenne and Becker muscular dystrophy. In addition to heart disease, these conditions are characterized by progressive weakness and wasting of muscles used for movement (skeletal muscles). People with DMD-associated dilated cardiomyopathy typically do not have any skeletal muscle weakness or wasting, although they may have subtle changes in their skeletal muscle cells that are detectable through laboratory testing. Based on these skeletal muscle changes, DMD-associated dilated cardiomyopathy is sometimes classified as subclinical Becker muscular dystrophy.
Read more about Duchenne and Becker muscular dystrophy.

How common is DMD-associated dilated cardiomyopathy?

DMD-associated dilated cardiomyopathy appears to be an uncommon condition, although its prevalence is unknown.

What genes are related to DMD-associated dilated cardiomyopathy?

DMD-associated dilated cardiomyopathy results from mutations in the DMD gene. This gene provides instructions for making a protein called dystrophin, which helps stabilize and protect muscle fibers and may play a role in chemical signaling within cells. The mutations responsible for DMD-associated dilated cardiomyopathy preferentially affect the activity of dystrophin in cardiac muscle cells. As a result of these mutations, affected individuals typically have little or no functional dystrophin in the heart. Without enough of this protein, cardiac muscle cells become damaged as the heart muscle repeatedly contracts and relaxes. The damaged muscle cells weaken and die over time, leading to the heart problems characteristic of DMD-associated dilated cardiomyopathy.
The mutations that cause DMD-associated dilated cardiomyopathy often lead to reduced amounts of dystrophin in skeletal muscle cells. However, enough of this protein is present to prevent weakness and wasting of the skeletal muscles.
Because DMD-associated dilated cardiomyopathy results from a shortage of dystrophin, it is classified as a dystrophinopathy.
Read more about the DMD gene.