DNA Testing Unlocks Secrets But Leaves Footprints

(Bloomberg) -- DNA tests are to 2018 what the iPhone was to 2007: a game-changing technology poised to reshape how we see ourselves and live our lives. So-called direct-to-consumer DNA testing companies like 23andMe, Ancestry and Helix advertise the ability to reveal your ancestry, inform you of your health status, and even guide you on how to exercise and eat -- all for $200 or less. Recent headlines have highlighted the role of the personal genomics revolution in solving crimes. Once your genetic information is out in the world, it can be hard to control how it is used.

1. What can you learn from a consumer DNA test?

A little bit of saliva can go a long way. The tests are nearly 100 percent accurate when it comes to telling you who you’re related to. DNA is great at identifying familial relationships like parents, grandparents, aunts, uncles and even second and third cousins. Beyond that, it gets fuzzy. A test by 23andMe Inc. can identify whether you might carry a marker for a certain genetic disease, but that doesn’t necessarily mean you’ll wind up developing it. And tests that claim to extract from your genome insights to improve your beauty, diet and fitness regimen are even less useful. In most cases, the science isn’t developed enough to tell you, say, how to maximize your workout routine based on your genetics.

2. How good is the science behind DNA testing?

When you swab your cheek or spit in a test tube, most consumer DNA testing companies ship your sample to a third-party lab for testing. From there, most companies don’t actually sequence your DNA but instead analyze it through a process called genotyping, which hunts for the presence of well-known bits of genetic code. Many genes associated with breast cancer, for example, have been thoroughly studied, so a test just has to determine whether a customer’s DNA has those variants. The genes that make you a superfast runner or that identify you as Irish are less well-studied. The accuracy of any one test depends on the data your DNA is being compared to. One 2009 journal article said consumer DNA tests were akin to horoscopes exploiting the human tendency to hunt for patterns in meaningless data.

3. So what does it mean when a test says I’m 25 percent Irish?

It’s a misconception that these tests can tell you where your DNA was in the past. Humans have constantly mixed and mingled throughout history, so it’s hard to say definitively where your ancestors might have lived. If a test tells you that you’re 25 percent Irish, what it actually means is that you are genetically similar to other people who are a part of the reference data set of Irish DNA that the company has collected. Because each company uses a different algorithm and data set, your results may vary based on which company you use. And because people of European ancestry are best represented in that data, results are likely to be more accurate for people with European origins. In other words: Take all this with one very large pinch of salt!

4. What if I find out I have a terrible disease?

Genetic tests don’t diagnose disease -- they identify whether you have genes that make you at risk of developing one. If you do have a marker for a disease, the probability of actually developing it varies widely. Only in rare cases, such as with Huntington’s disease, the genetic disorder in which nerve cells in the brain break down over time, does having the gene mean you are almost certain to develop the disease. It’s worth noting that 23andMe is the only direct-to-consumer DNA testing company with U.S. Food and Drug Administration approval to tell customers about their disease risk, and so far the company only offers this for fewer than a dozen conditions. Any troublesome result should be verified by a doctor: Sometimes the tests are wrong.

5. How popular are consumer DNA tests?

Very! On Black Friday weekend last year, Ancestry.com Inc. alone sold 1.5 million genetic testing kits. The direct-to-consumer industry has grown from about $15 million in sales in 2010 to more than $99 million in 2017, and is projected to reach $310 million by 2022, according to market-research company Kalorama Information.

6. Are the tests as popular outside the U.S.?

DNA testing is definitely a trend that took off in the U.S, where tracing one’s immigrant roots is a longstanding obsession. But major companies like Ancestry and 23andMe also sell their tests in other countries, where they are starting to catch on. And DNA testing upstarts are starting to boom in places like China and the U.K.

7. Could employers or insurers get access to my genetic info?

In 2008, Congress passed the Genetic Information Nondiscrimination Act, or GINA, with the intent of protecting people against health-insurer and employer discrimination based on genetic information. The trouble is, GINA has a lot of loopholes. The law doesn’t apply to life-insurance companies, for example. This means that if you took a consumer DNA test, a life insurer could request that data and make coverage decisions based on the findings.

8. Can law enforcement get my DNA results?

Possibly. Most company privacy policies spell out clearly that they may have to share your genetic information with law enforcement if a court order compels it. Ancestry and 23andMe release annual transparency reports, and in recent years neither company has complied with law enforcement requests for consumer genetic information. But it turns out company permission may not be necessary. In April, police in Sacramento County, California, believe they cracked the long-cold case of the Golden State Killer by matching DNA from a crime scene to genetic data belonging to the suspect’s relatives that had been posted on an open-source genealogy website, without even seeking the website’s permission. Police have used the same method several times since, raising questions about how the growing repositories of consumers’ most intimate data could be used by authorities.

9. Who else could access my genetic information?

Companies frequently share anonymized consumer genetic data with third parties, including researchers and business partners. It’s all there in the fine print! Hacking is also a risk. Recently, the genealogy website MyHeritage.com revealed it was the victim of a major breach, though it appears no genetic information was accessed by the hackers. And many consumers don’t realize that when they share their genetic information, they’re also sharing details about their relatives.

10. Is the DNA testing industry regulated?

Sort of. Critics complain that existing rules don’t allow adequate oversight of the biggest testing companies. The FDA cracked down on 23andMe in 2013 for telling consumers about their disease risk. It took another four years before the agency granted the company the right to do so, and so far, it’s the only consumer DNA testing company to seek FDA approval for its product. Beyond that, the FDA has pretty much stayed out of the debate over how consumer tests should be regulated. U.S. Senator Chuck Schumer has asked the Federal Trade Commission to investigate the claims and privacy practices of testing companies. In Europe, recently enacted privacy-protection rules known as the General Data Protection Regulation could provide consumers more transparency about how their data is used.

The Reference Shelf

©2018 Bloomberg L.P.