It's getting easier than ever to stumble across single genes linked to potential heart risks, but deciding what to do with such findings requires caution, says a new report aimed at helping health care professionals and their patients navigate the process.
The report, published Monday as a scientific statement from the American Heart Association in its journal Circulation: Genomic and Precision Medicine, addresses what to do when testing uncovers genetic abnormalities, or variants, associated with cardiovascular disease.
Such variants often are uncovered when people are screened for non-cardiac diseases or through home DNA testing kits. But the report says that such "incidentally" identified single-gene variants may or may not be risk factors for disease and spells out ways to interpret results carefully.
"The scope and use of genetic testing have expanded greatly in the past decade with the increasing ease and reduced cost of DNA sequencing," Dr. Andrew P. Landstrom, chair of the report's writing committee, said in a news release. "Where we would once look for genetic changes in a handful of genes, we can now sequence every gene and, potentially, the whole genome, allowing us to make genetic diagnoses that would have been impossible in the past."
But the increased testing brings more surprises, including finding genes that might be associated with cardiovascular disease, said Landstrom, an associate professor of pediatrics and cell biology at Duke University School of Medicine in Durham, North Carolina. "If we interpret these incidental variants incorrectly, it may lead to inappropriate care, either by suggesting patients have a risk of cardiac disease when they do not or by not providing care to those with increased risk for a serious condition."
The report offers a framework for health care professionals to assess individual variants, communicate findings with patients and their families and, when needed, create a multidisciplinary care team.
The authors strongly encourage pretest genetic counseling for patients to discuss the possibility of unexpected findings, decide whether such findings will be communicated and look at potential implications for family members.
If an incidental variant for heart disease is found, the report suggests a way to classify the finding as benign, uncertain or disease-causing. It says health care professionals should relay information to patients only about variants that are known to be associated with cardiovascular disease and only if patients agreed to be informed.
For variants that may increase the risk of cardiovascular disease, the report suggests that a health care expert, preferably a specialist who is part of a multidisciplinary team, conduct a family history and a medical evaluation to look for symptoms.
Landstrom said it was important to consult with genetics specialists "to custom tailor an evaluation and treatment plan" to the individual and the variant to ensure the highest level of care possible.
The variant itself needs to be re-evaluated periodically, because its link to disease may be reclassified, the report says.
Depending on the variant, a full evaluation could lead to medical intervention, regular heart-specific tests or having relatives genetically screened.
According to the report, the American College of Medical Genetics and Genomics recognizes 42 clinically treatable, secondary variant genes that increase the risk of sudden cardiac death, heart failure and other types of cardiovascular disease.
The report is the first to focus on inherited single-gene conditions that can be passed on within families, such as hypertrophic cardiomyopathy (a thickening of the heart walls) or long QT syndrome, where the heart electrically resets slower than normal after each contraction, sometimes leading to fainting, arrhythmias or sudden death.
"The list of incidental variants related to cardiovascular disease continues to evolve," Landstrom said. "This statement provides a foundation of care that may help people with a CVD-related genetic variant and their health care professionals take the next step in determining the individual and familial risk that a variant may or may not carry."