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DMD-associated dilated cardiomyopathy
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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.
How do people inherit DMD-associated dilated cardiomyopathy?
DMD-associated dilated cardiomyopathy has an X-linked pattern of inheritance. The DMD gene is located on the X chromosome, which is one of the two sex chromosomes. In females (who have two X chromosomes), a mutation in one of the two copies of the gene in each cell usually leads to relatively mild heart disease that appears later in life. In males (who have only one X chromosome), a mutation in the only copy of the gene in each cell causes more severe signs and symptoms that occur earlier in life. A characteristic of X-linked inheritance is that fathers cannot pass X-linked traits to their sons.
Where can I find information about diagnosis or management of DMD-associated dilated cardiomyopathy?
These resources address the diagnosis or management of DMD-associated dilated cardiomyopathy and may include treatment providers.
General information about the diagnosis and management of genetic conditions is available in the Handbook. Read more about genetic testing, particularly the difference between clinical tests and research tests.
To locate a healthcare provider, see How can I find a genetics professional in my area? in the Handbook.
Where can I find additional information about DMD-associated dilated cardiomyopathy?
You may find the following resources about DMD-associated dilated cardiomyopathy helpful. These materials are written for the general public.
You may also be interested in these resources, which are designed for healthcare professionals and researchers.
What other names do people use for DMD-associated dilated cardiomyopathy?
What if I still have specific questions about DMD-associated dilated cardiomyopathy?
Where can I find general information about genetic conditions?
The Handbook provides basic information about genetics in clear language.
These links provide additional genetics resources that may be useful.
What glossary definitions help with understanding DMD-associated dilated cardiomyopathy?
arrhythmia ; benign ; cardiac ; cardiomyopathy ; cell ; chromosome ; dilated ; gene ; heart failure ; inheritance ; muscular dystrophy ; mutation ; pattern of inheritance ; prevalence ; protein ; sex chromosomes ; skeletal muscle ; wasting
You may find definitions for these and many other terms in the Genetics Home Reference Glossary.
See also Understanding Medical Terminology.
References (7 links)
The resources on this site should not be used as a substitute for professional medical care or advice. Users seeking information about a personal genetic disease, syndrome, or condition should consult with a qualified healthcare professional. See How can I find a genetics professional in my area? in the Handbook.