Direct-to-Consumer Genetic Testing
When I was a new Genetic Counselor, and I told people what I do, I was often met with confused looks, or the occasional (bad) joke about giving genes psychotherapy. Now when I tell them, they often whip out their phone and ask me to take a look at their 23andMe results. More and more companies are offering genetic testing directly to consumers like you, without middle-men (and middle-women) like me. When deciding to take an in-home genetic test, there are some things you should consider.
Types of Direct-to-Consumer Tests
There are plenty of genetic testing companies that claim they can tell you everything about yourself, from where your ancestors are from, to whether you are at risk of medical conditions, to which wine you’re more likely to enjoy. While some may seem like harmless pastimes, you should always be aware of what the potential results can or can’t tell you.
All genetic testing runs the risk of finding something we didn’t expect. In clinic, we call these incidental findings; things we weren’t really looking for, but found anyways. These could range from relatively harmless (oh no, my wine club membership is all wrong!), to life-shattering information. Ancestry services that link you to relatives have helped many families reconnect with distant relatives, but they have also revealed buried family secrets. Finding half-siblings no one knew existed; finding out your father isn’t genetically related to you; finding out that your mom and dad are cousins; finding out that your very Italian family is actually Irish… these are all possible outcomes of genetic testing.
Some studies have that found a large portion of direct-to-consumer results are inaccurate. If you have had a direct-to-consumer test, it’s best to follow-up with your doctor before taking any action based on those results. Confirming the results in a clinical lab with a good reputation should always be done before making medical decisions.
Also beware of what the test is NOT detecting. No genetic test can rule out everything, but DTC tests are notoriously limited in their scope. Many DTC test are looking at SNPs (pronounced “snips”), which are single letter changes across various parts of your genome. They’re not looking at genes in their entirety, just a letter here and there. Just because you don’t have one of the SNPs they looked at related to a condition, doesn’t mean you don’t have any of the thousands of other changes that are.
SNP-based risk assessment or ancestry testing is also the reason that different companies can give you different results for the same condition or heritage. One company might be looking at SNPs #1, 2 & 3, while another company might be looking at SNPs # 3, 4 & 5. They’re basing their assessments on different, and very limited, information.
Many of the health risks that DTC companies claim to assess are based on many different factors besides just genetics. Family history and lifestyle are often a better indicator of risk than SNPs are. Don’t ignore your family history of heart disease because your genetic test results said you were in the clear.
Go in with Eyes Open
If you do decide to have a genetic test, whether for fun on your own, or for a clinical reason with your doctor, make sure you are prepared for what the testing could mean for you. Read the consent form carefully, and check to see how your data will be used or shared. All tests have limitations, and not every testing service is reliable. You can’t un-learn something about yourself or your family once it’s been revealed. So please, test responsibly.