Genetic testing for cardiomyopathy is often overlooked but an important component of disease management. It can help to confirm a diagnosis by identifying the genetic mutation that causes cardiomyopathy. In rare cases where cardiomyopathy appears to be caused by another disease (secondary cardiomyopathy), additional genetic tests may be needed.
A person’s DNA (deoxyribonucleic acid) and RNA (ribonucleic acid) carries the genetic information responsible for the organization and functioning of body cells. A genetic test examines a person’s DNA, RNA, chromosomes, proteins or metabolites and identifies genetic abnormalities related to an inheritable disorder. Testing involves extracting DNA through saliva, blood, or heart tissue.
Purpose of Testing
With cardiomyopathy, genetic testing is primarily used for diagnostic purposes to identify a disease-causing genetic mutation in a child with signs or symptoms. It is also used for screening and predictive or pre-symptomatic purposes. Since cardiomyopathy can be familial without symptoms, other family members can be tested for the identified genetic mutation to determine if they unknowingly have cardiomyopathy. Testing may reveal that a family member has the genetic mutation for cardiomyopathy but has not developed the disease yet. These test results can provide guidance on which family members need to be monitored and which members can discontinue being screened by echocardiogram and EKG.
Genetic Testing Process
The process of genetic testing begins with a medical consultation with a geneticist and genetic counselor. The first step involves a pedigree analysis which is a genetic representation of a family tree in the form of a diagram. The geneticist, working with the pediatric cardiologist, will evaluate your child’s cardiomyopathy type, symptoms, and medical condition to recommend a specific genetic testing plan for your family.
Genetic testing can be performed in a clinical setting or a research lab setting. Fee based genetic testing, with results communicated to the family, are done in a commercial laboratory under Clinical Laboratory Improvement Amendment (CLIA) regulations. There are no fees with research testing done at an academic medical center, but it may not be possible for results to be given to patients in a timely manner.
There are many factors for families to consider before genetic testing. The impact of test results on health and life insurance coverage should be weighed against the impact on treatment and screening of family members. The following points will most likely be covered by the geneticist and genetic counselor:
- Genetic tests that are appropriate for your child and your family
- Accuracy of the recommended genetic tests
- Process of genetic testing
- Cost of testing and insurance coverage
- Processing time for test results
- Possible test results and the interpretation of findings
- Privacy concerns on genetic testing results
- Possibility of discrimination by health insurer or employer
Interpreting Test Results
Genetic testing results usually take several weeks to become available. A geneticist or genetic counselor will explain the test results and answer questions related to:
- Whether a genetic mutation (single or multiple) was identified to cause cardiomyopathy
- Whether additional diagnostic testing is needed to confirm another disorder associated with cardiomyopathy
- When test results should be communicated to children
- Whether the treatment plan needs to be modified
- Who should get genetic testing in the immediate and extended family
If a genetic test identifies a genetic mutation in your child, it is important to assess the risk of cardiomyopathy in other family members. Additional questions related to family testing include:
- Which family members are diagnosed with cardiomyopathy
- Whether diagnosed family members have the same genetic mutation as your child
- Which members have tested positive for the genetic mutation but have not developed cardiomyopathy
- Which family members should continue to be screened on a regular basis
- What are the implications for family planning
While genetic testing can confirm and exclude at-risk family members, it cannot predict whether an asymptomatic individual with the genetic mutation will develop the disease. It also cannot predict when symptoms will manifest nor the severity of the disease.
For additional information about genetic testing, view CCF’s educational video, Know Your Heart: Genetic Testing for Cardiomyopathy Families. This short video provides families with a basic overview of the genetic testing process and covers what genetic testing is, when it should be considered, how the process works, and why it can be beneficial to certain families.