A little knowledge goes a long way … but could it go too far if taken out of context? With genomic data becoming increasingly available to clinicians, providers are having to learn to navigate the line between sharing important information and needlessly scaring a patient.
A new study led by investigators at Vanderbilt University Medical Center found a genetic test suggesting a patient might be at increased risk for potentially fatal arrhythmias very often wasn’t as ominous as it first appeared. Out of the group of 2,022 patients, 63 were identified who had genetic variations considered to be “potentially pathogenic.” However, the electrocardiograms of the individuals in this group were no different than those without the genetic variances.
Sara Van Driest, MD, PhD, an assistant professor of Pediatrics and Medicine at VUMC and the paper’s first author, said the results “warn us to be very careful about returning genetic results, particularly to people who have no signs or symptoms of heart disease.”
The researchers fully expected to find genomic variants when sequencing healthy people. Van Driest said everyone has some variations that could potentially cause disease. Yet, those ‘red herrings’ are often just that – harmless anomalies that don’t progress to disease. Van Driest noted, “We were interested in learning what the potential implications were for incidental findings in these genes.”
She explained the study came about as part of the eMERGE (Electronic Medical Records & Genomics) Network. Funded by the National Human Genome Research Institute, Vanderbilt is actively involved in this national, multicenter research project and serves as the network’s coordinating center. According to the website, eMERGE combines DNA repositories with EMR systems for large scale, high-throughput genetic research in support of implementing genomic medicine.
As the field of genomic medicine continues to grow, the list of gene variants linked to different diseases also grows. However, Van Driest pointed out, “The difficulty is so far nearly all the data we have to base our decisions on comes only from people or families with the disease … people who have already been diagnosed or with very high risk.”
She continued, “It’s only when we take a step back and look at both people with and without the disease that we can determine how accurate the variant is in actually predicting the disease.” Simply having a variant, even one that does increase risk, doesn’t necessarily mean the disease will manifest, she stated.
Dan Roden, MD, senior author and professor of Medicine and Pharmacology at VUMC, added there has been a big push to return every genetic result back to patients. “This is one way of saying, ‘Hold on. Let’s make sure we’re doing this the right way,’” he noted of the study’s findings.
The team found that relying solely on genetic testing without consideration of the ECG and other data found in an individual’s EMR might needlessly alarm the patient and could also lead to expensive and unnecessary treatments – in this case, an implantable defibrillator.
“I think we need to educate clinicians, as well as patients, that with these variants, we’re still learning what the real clinical implications are,” Van Driest said. “A genetic variant doesn’t determine their fate.”
She added there are a couple of downstream outcomes that would ideally develop from this study: “1) We need to have large sequencing efforts in extremely large cohorts of patients so we can determine how impactful the variants are, and 2) we should never look at a variant in isolation.”
The good news is that by studying the genomic data of a large mix of patients with and without disease and using other tools at hand including family history, medical records, and prior test and lab results, researchers should begin to get a handle on how much weight each genetic variation carries over time.
Indeed, some variants have already been well characterized, but many others have not. “We just have a lot more to learn,” Van Driest concluded.
For more information, results of the study were published last month in the Journal of the American Medical Association.
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