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Genetic Linkage

Genetic Counselors Best to Interpret DTC Genetic Tests

Genetic counselors know more about genetic testing than other health care professionals.
Can health care providers adequately explain results from direct-to-consumer (DTC) DNA tests to patients? “Consumer Perceptions of Interactions With Primary Care Providers After Direct-to-Consumer Personal Genomic Testing,” a study published March 1, suggests a disconnect between what consumers expect and what their doctors can deliver.

Genetic counselors are the obvious professionals to fill that growing need – they’re the experts when it comes to genetics, genomics, DNA testing, and people.

Genetic Testing Ups and Downs

Researchers from the Impact of Personal Genomics Study group at the University of Michigan gave an online survey to people who’d taken tests from 23andMe or Pathway Genomics, two U.S. companies that remain in the DTC space after several companies debuted their offerings at the American Society of Human Genetics annual meeting in late 2007.

Six years later, FDA banned 23andMe from marketing certain genetic tests DTC as “information.” The agency ruled that the company’s "Personal Genome Service" violated the Federal Food, Drug and Cosmetic Act, but on February 19, 2015, okayed a well-validated carrier test for Bloom syndrome. Pathway Genomics offers standard genetic tests that must be ordered through a health care provider, and also the DTC DNA Insight® General Health and Wellness Genetic Tests.

Despite the happy ads, DTC doesn’t mean simple, and the potential for misinterpretation and subsequent unnecessary and possibly even dangerous interventions, from patients and/or their providers, is real. Some knowledge of genetics is required for context. For example, certain DTC tests, particularly for multifactorial conditions, are risk estimates based on genome-wide association studies (GWAS) that track many common single nucleotide polymorphisms (SNPs). That's far less clinically meaningful than a traditional and well-validated genetic test that detects a specific "causal variant" (aka "mutation").

A GWAS result might actually mean “your gene variants account for 4 percent of the observed variation in blood pressure in your population” rather than “you’re going to develop heart disease from hypertension.” Would the average consumer know that distinction? With high levels of uncertainty and complex testing, it’s little wonder that some physicians are not entirely comfortable when a patient comes in waving DTC findings. In one study from 2012, only 15% of 382 surveyed family and internal medicine practitioners in North Carolina felt prepared to answer questions about DTC genetic tests.

Happy With Testing, With Docs, Not So Much

The new study considered serious DNA-based tests, such as pharmacogenomics results that might affect prescribing, and specific disease risks, rather than frivolous DTC fare like eye color or whether cilantro tastes good. Surveys were taken 2 weeks and 6 months after testing.

About two-thirds of the 947 customers of 23andMe and 517 of Pathway Genomics hung in for the 6-month evaluation, with 1026 of them weighing in on interactions with health care providers.

At the study’s start, nearly two-thirds of the participants planned to discuss results with a provider, but only 27% actually did so. For reasons they cited not considering results important enough to share, no time, and privacy concerns.

The paper, which is unfortunately behind a paywall, is data-dense. Responses are parsed by whether participants discussed results with their “PCP, other HCP only, no HCP, and no response.” That is apparently the extent of the type-of-provider taxonomy. Here’s what jumps out at me:

• People were quite satisfied with the DTC testing experience, understood most results, and found the information helpful.DNA data should be included in the medical record.

• Most felt that DNA data should be included in the medical record.

• Input from health care providers isn’t really necessary to understand test results.

Most interesting was response to the statement “I believe my PCP understands genetics well enough to advise me on the implications of my results for my health”: 10% strongly disagreed, 18% somewhat disagreed, 38% neither agree nor disagree, 24% somewhat agree, and 10% strongly agree. That is, all over the map.

The paper includes a few intriguing comments and two cases, but it’s difficult to tell to what degree these are cherry-picked. While it was easy to envision “[My] PCP backed away from the report like it was something to be afraid of,” I was cheered by this observation: “He was not interested in the printable summary of my results without digging into the underlying genome data. But the underlying data was hard to get and impossible to print out, so I couldn’t really share it with him.”

I hope the dismissive docs – one called DTC testing “entertainment” -- may soon be outnumbered by those wanting to learn more.

A Failure to Communicate?

The mismatched expectations may have come from company advice to discuss test results with HCPs, assuming a familiarity with genetics and genomics that might not exist, at least not widely and not yet.

Conclude the researchers, “Given the increasing importance of genetic considerations in primary care over the past decade and repeated calls for physician education initiatives in genomics, all PCPs should have adequate clinical skills to at least engage in a discussion about genetic testing that describes its benefits and limitations and provides an account of why further action is or is not recommended.”

Some providers may actually learn from their patients. Wrote one participant: “I think by my diligence I can help expose my [doctors] to consider the advantages of such genetic information. I took this test, knowing full well that it was a new tool in the medical treatment and diagnosis. I saw it as my part to participate in this new era in medicine.”

Genetic Counselors Are the Experts

Despite the density of the data in the study, one word conspicuously absent is “counselor,” as in “genetic counselor.” Presumably this type of expert is subsumed under “other HCP.”

A genetic counselor is the ideal professional with whom to discuss any genetic test results, from the seemingly trivial direct-to-consumer ability-to-taste-cilantro variety to cancer tests. I've seen physicians flummoxed over the abbreviation VUS, for example, on a BRCA test result, even when I explain "variant of unknown significance." Failure of physicians to recognize the potential importance of a VUS has led to some disasters, such as told in Everyone's Worst Nightmare or in this recent article in the New York Times.

Genetic counselors have both the technical knowledge and the skills to discuss test results with patients – and for much more than 15 minutes.

Many testing companies have genetic counselors to talk to, or consult the National Society of Genetic Counselors to find one. DTC genetic testing and personal genomics are here to stay.

(I have provided genetic counseling, albeit very rarely, for a large private medical practice since 1983. I am not presently a member of the NSGC. Thanks, NHGRI, for the graphic. This post was originally published March 10 on my DNA Science blog at Public Library of Science.)







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