At-home genetic test kits face scrutiny for providing information that may provide consumers with an incomplete picture of their genetic health risks and ancestry
Genetic testing for disease risk and heritage are hugely popular. But though clinical laboratory and pathology professionals understand the difference between a doctor-ordered genetic health risk (GHR) test and a direct-to-consumer (DTC) genetic test, the typical genetic test customer may not. And misunderstanding the results of a DTC at-home genetic test can lead to confusion, loss of privacy, and potential harm, according to Consumer Reports.
To help educate consumers about the “potential pitfalls” of at-home DTC testing kits offered by companies such as Ancestry and 23andMe, Consumer Reports has published an article, titled, “Read This Before You Buy a Genetic Testing Kit.” The article covers “four common claims from the manufacturers of these products, whether they deliver, and what to know about their potential pitfalls.”
Are Genetic Ancestry Tests Accurate?
Ancestry and 23andMe are the DTC genetic test industry leaders, with databases of genetic information about 18 million individuals and 10 million individuals respectively. According to a Consumer Reports survey, as of October 2020 about one in five Americans had taken a DTC genetic test. Reported reasons for doing so included:
- 66% of respondents wanted to learn more about their ancestry.
- 20% wanted to locate relatives.
- 18% wanted to learn more about their health.
- 11% wanted to learn if they have or are a carrier for any medical conditions.
- 3% wanted to get a medical test they could not get through their doctor.
As Consumer Reports notes, doctor-ordered genetic health risk (GHR) testing typically aims to answer a specific question about a patient’s risk for a certain disease. DTC at-home genetic testing, on the other hand, examines a “whole range of variants that have been linked—sometimes quite loosely—to a number of traits, some not related to your health at all.
“Think of it this way: When your doctor orders genetic testing, it’s akin to fishing for a particular fish, in a part of the ocean where it’s known to live,” Consumer Reports noted, “A DTC test is more like throwing a net into the ocean and seeing what comes back.”
In its article, Consumer Reports addressed four common DTC genetic test claims:
- The Tests Can Find Far-Flung Relatives: While the tests can unearth people in its database whom you might be related to, 9% of respondents in the Consumer Reports survey discovered unsettling information about a relative.
- Testing Can Uncover Where Your Ancestors Are From: Genetic tests may show the percentage of your DNA that comes from Europe or Asia or Africa, but accuracy depends on how many DNA samples a company has from a particular region. As genetic test manufacturers’ reference databases widen, a customer’s genetic ancestry test results can “change over time.” Also, finding a particular variation in genetic code does not definitively place someone in a specific region, or ethnic or racial group.
- Genetic Tests Can Reveal Your Risk for Certain Diseases: Testing companies such as 23andMe are authorized by the Food and Drug Administration (FDA) to offer physician-mediated tests, which are analyzed in a federally-certified clinical laboratory. However, test results may provide a false sense of security because DTC tests look for only select variants known to cause disease.
- The Tests Can Tell What Diet Is Best for You: Incorporating genetic information into diet advice has the potential to be transformative, but the science is not yet there to offer personalized nutritional advice.
Consumer Reports pointed to a 2020 study published in the MDPI journal Nutrients, titled, “Direct-to-Consumer Nutrigenetics Testing: An Overview,” which evaluated 45 DTC companies offering nutrigenetics testing and found a need for “specific guidelines” and “minimum quality standards” for the services offered. For example, the study authors noted that more than 900 genetic variants contribute to obesity risk. However, weight-loss advice from DTC test companies was based on a “limited set of genetic markers.”
In the Consumer Reports article, Mwenza Blell, PhD, a biosocial medical anthropologist and Rutherford Fellow and NUAcT Fellow at Newcastle University in the United Kingdom, said “genetic ancestry tests are closer to palm reading than science.”
GHR Test Results Also Can Produce Confusion
In an article, titled, “The Problem with Direct-to-Consumer Genetic Tests,” Scientific American reviewed consumer-grade GHR products and came to similar conclusions regarding health-based assessments. The article’s author, oncologist Heather Cheng, MD, PhD, Director of the Prostate Cancer Genetics Clinic at the
Seattle Cancer Care Alliance and an Associate Professor of Oncology at the University of Washington, fears consumers “miss important limitations on a test’s scope” or “misunderstand critical nuances in the results.”
Cheng says the ability to use flexible or health savings accounts (HSAs) to cover the cost of 23andMe’s GHR assessments, as well as the FDA’s approval of 23andMe’s Personal Genome Service Pharmacogenetic Reports test on medication metabolism, may have added to the confusion.
“This may further mislead people into thinking these tests are clinically sound. Again, they are not,” Cheng wrote.
As an oncologist, Cheng is particularly concerned about consumer GHR testing for heritable cancer risk, which screen for only a handful of genetic variants.
“The results are inadequate for most people at high risk of cancers associated with inherited mutations in BRCA1 or BRCA2 genes, including families whose members have experienced ovarian cancer, male breast cancer, multiple early breast cancers, pancreatic cancer, or prostate cancer,” Cheng wrote. “Put simply, this recreational test has zero value for the majority of people who may need it for true medical purposes.”
DTC genetic health-risk assessments may one day lead to consumers collecting samples at home for tests that aid in the diagnosis of disease. In the meantime, clinical laboratory professionals can play a role in educating the public about the limitations of current DTC genetic test offerings.
—Andrea Downing Peck