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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.
DMD-associated dilated cardiomyopathy appears to be an uncommon condition, although its prevalence is unknown.
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.
Changes in this gene are associated with 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.
These resources address the diagnosis or management of DMD-associated dilated cardiomyopathy and may include treatment providers.
You might also find information on the diagnosis or management of DMD-associated dilated cardiomyopathy in Educational resources (http://www.ghr.nlm.nih.gov/condition/dmd-associated-dilated-cardiomyopathy/show/Educational+resources) and Patient support (http://www.ghr.nlm.nih.gov/condition/dmd-associated-dilated-cardiomyopathy/show/Patient+support).
General information about the diagnosis (http://ghr.nlm.nih.gov/handbook/consult/diagnosis) and management (http://ghr.nlm.nih.gov/handbook/consult/treatment) of genetic conditions is available in the Handbook. Read more about genetic testing (http://ghr.nlm.nih.gov/handbook/testing), particularly the difference between clinical tests and research tests (http://ghr.nlm.nih.gov/handbook/testing/researchtesting).
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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.
For more information about naming genetic conditions, see the Genetics Home Reference Condition Naming Guidelines (http://ghr.nlm.nih.gov/ConditionNameGuide) and How are genetic conditions and genes named? (http://ghr.nlm.nih.gov/handbook/mutationsanddisorders/naming) in the Handbook.
Ask the Genetic and Rare Diseases Information Center (http://rarediseases.info.nih.gov/GARD/).
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 (http://www.ghr.nlm.nih.gov/glossary).
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