Dilated cardiomyopathy is a disease of the heart muscle, usually starting in your heart's main pumping chamber (left ventricle). The ventricle stretches and thins (dilates) and can't pump blood as well as a healthy heart can. The term "cardiomyopathy" is a general term that refers to the abnormality of the heart muscle itself.
Mutations in more than 30 genes have been found to cause familial dilated cardiomyopathy. These genes provide instructions for making proteins that are found in cardiac muscle cells called cardiomyocytes.
Familial dilated cardiomyopathy has different inheritance patterns depending on the gene involved.
In 80 to 90 percent of cases, familial dilated cardiomyopathy is inherited in an autosomal dominant pattern, which means one copy of the altered gene in each cell is sufficient to cause the disorder. In most cases, an affected person inherits the mutation from one affected parent. However, some people who inherit the altered gene never develop features of familial dilated cardiomyopathy. (This situation is known as reduced penetrance.) Other cases result from new mutations in the gene and occur in people with no history of the disorder in their family.
In rare instances, this condition is inherited in an autosomal recessive pattern, which means both copies of the gene in each cell have mutations. The parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene, but they typically do not show signs and symptoms of the condition.
In other rare cases, this condition is inherited in an X-linked pattern. In these cases, the gene associated with this condition 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 increases the risk of developing heart disease, but females with such a mutation may not develop familial dilated cardiomyopathy. In males (who have only one X chromosome), a mutation in the only copy of the gene in each cell causes familial dilated cardiomyopathy. A characteristic of X-linked inheritance is that fathers cannot pass X-linked traits to their sons.
Dilated cardiomyopathy might not cause symptoms, but for some people it can be life-threatening. A common cause of heart failure — the heart's inability to supply the body with enough blood — dilated cardiomyopathy can also contribute to irregular heartbeats (arrhythmias), blood clots or sudden death.
If you have dilated cardiomyopathy, you're likely to have signs and symptoms of heart failure or arrhythmias caused by your condition. Signs and symptoms include:
Complications from dilated cardiomyopathy include:
Doctors usually treat dilated cardiomyopathy with a combination of medications. Depending on your symptoms, you might need two or more of these drugs:
Implantable devices used to treat dilated cardiomyopathy include:
You may be a candidate for a heart transplant if medications and other treatments are no longer effective.
Genetics Home Reference - www.ghr.nlm.nih.gov
The American Heart Association - www.heart.org