What is Dilated Cardiomyopathy?
A disease of the heart muscle, dilated cardiomyopathy (DCM) affects the heart’s ventricles and atria, which are the lower and upper chambers of the heart, respectively. In patients with DCM, the heart chambers dilate and the heart muscle doesn’t contract normally, making the heart unable to pump blood very well. Over time, the heart becomes weaker, which could result in heart failure or cardiac arrest in more severe cases. DCM is a common cause of heart failure, and is the most common diagnosis in patients who require cardiac transplantation.
DCM affects individuals of both sexes and all ethnicities, but is more commonly diagnosed in middle-aged adults. It’s estimated that DCM happens in 36 out of 100,000 individuals, but it could be more prevalent as many patients with DCM are asymptomatic.
What causes Dilated Cardiomyopathy?
There are numerous causes of DCM, including severe coronary artery disease, heart valve abnormalities, alcoholism, viral infection, along with certain drugs that can damage the heart. But there are also many cases of FCM that are described as idiopathic, where the cause is unknown. And among idiopathic cases, a significant percentage have genetic links. In addition, DCM can also occur as a late manifestation of hypertrophic heart disease.
Approximately 40 percent of patients with DCM have a familial or genetic basis to their condition. Transmission can occur in autosomal dominant, autosomal recessive, or X-linked pattern depending on the causative genetic abnormality, though autosomal dominant transmission is most common.
Why test for Dilated Cardiomyopathy?
As there is a high probability of genetic links in cases of DCM that have no known causes, genetic testing in a patient manifesting symptoms can clarify the diagnosis and assist in the medical management of family members. If a genetic test finds a mutation that is likely to cause the disease in a patient, family members can undergo more simplified testing for the initial mutation found – this allows for genetic identification of at-risk family members who are clinically asymptomatic. With early identification, preventative treatment could be carried out to halt or reverse the progression of the disease. Genetic testing can also be used for prenatal or preimplantation genetic diagnosis.
How does the test work?
The DCM genetic test is a blood test ordered by your physician. Your DNA is extracted from the blood and analyzed by searching specifically for mutations in any genes that are associated with DCM. The test takes approximately 10 weeks to complete, and the results will be sent to your physician, who will explain the test results to you.
We will need two tubes of blood (about 7 to 10ml) and a signed consent form from you to send to the laboratory. We recommend genetic counselling before genetic tests are ordered to discuss the implications of the testing and potential results.