A new scientific statement from the American Heart Association recommends that genetic testing for inherited cardiovascular disease should be reserved for four specific types of heart diseases – cardiomyopathies, thoracic aortic aneurysms and dissections, arrhythmias, and familial hypercholesterolemia – and should enlist skilled geneticists and genetic counselors in the care team.
Dr. Kiran Musunuru
The guidance comes in a scientific statement published online in the journal Circulation: Genomic and Precision Medicine.
Kiran Musunuru, MD, PhD, MPH, ML, chair of the writing group for the scientific statement, described in an interview the rationale for publishing the statement at this time. “There was no prior single statement that summarized best practices for the whole gamut of inherited cardiovascular diseases in adults, only statements for individual diseases,” he said in an interview. “With genetic testing seeing explosive growth in the past few years, both in the clinical setting and with direct-to-consumer testing, we felt that cardiovascular practitioners would benefit from having a single document to serve as a general resource on genetic testing.”
The statement describes two types of patients who would be suitable for genetic testing for cardiovascular disease (CVD), Dr. Musunuru noted: “Patients who have been diagnosed with or are strongly suspected to have a cardiovascular disease that is often inherited and family members of patients who have been diagnosed with an inherited cardiovascular disease and found by genetic testing to have a mutation that is felt to be the cause of the disease.”
The statement also spells out two crucial elements for genetic testing: thorough disease-specific phenotyping – that is, using genetic information to identify the individual’s disease characteristics and a comprehensive family history that spans at least three generations. Testing should only proceed after patients has had genetic counseling and made a shared decision with their doctors.
“Genetic counseling is absolutely essential both before genetic testing to educate patients on what genetic testing entails and what potential results to expect, as well as the risks of testing; and after genetic testing, to review the results of the genetic testing and explain the potential consequences for the patient’s health and the health of family members, including children,” Dr. Musunuru said.
The process should involve board-certified geneticists or at least cardiovascular specialists well-versed in genetics and genetic counselors, the statement noted. The latter are “critical” in the care team, Dr. Musunuru said.
After the decision is made to do genetic testing, the next step is to decide the scope of the testing. That can range from targeted sequencing of a single gene or a few genes linked to the disease to large gene panels; the latter “may not increase the likelihood of clinically actionable results in adult patients,” Dr. Musunuru and colleagues wrote.
But genetic testing is no guarantee to identify a cause or confirm a diagnosis of CVD, the statement noted. “The yield for any genetic testing for any inherited cardiovascular disease remains <100%, usually much less than 100%,” the writing committee stated.
Dr. Musunuru explained that the results can sometimes be inconclusive. “In many cases, genetic testing reveals a mutation that is uninterpretable, what we call a variant of uncertain significance,” he said. “It is not clear whether the mutation increases the risk of disease or is entirely benign, which makes it very challenging to counsel patients as to whether anything should be done about the mutation.”
Even in a diagnosed patient the test results can be uncertain. “This makes it challenging to explain why the patient has the disease and whether any of the family members are at risk,” Dr. Musunuru said.
According to the statement, providers should encourage patients with a confirmed or likely pathogenic variant for CVD to share that information with “all of their at-risk relative,” the statement noted, suggesting “family letters” given to patients are a way to navigate HIPAA’s privacy limits.
The statement was written on behalf of the American Heart Association’s Council on Genomic and Precision Medicine; Council on Arteriosclerosis, Thrombosis and Vascular Biology; Council on Cardiovascular and Stroke Nursing; and Council on Clinical Cardiology.
Dr. Musunuru and writing group members have no relevant financial relationships to disclose.
SOURCE: Musunuru K et al. Circ Genom Precis Med. 2020 Jul 23. doi: 10.1161/HCG.0000000000000067.