ATLANTA — At-home DNA kits are a popular holiday gift.

They entice you to find out about your ancestry and learn about your health, but when it comes to showing your risk for getting certain diseases in the future, doctors say watch out.

For only $129, the company 23andMe says they’ll find your ancestry and test your genetic risk factor for certain diseases including Type 2 Diabetes, late-onset Alzheimer’s, and BRCA 1 and BRCA 2, commonly associated with breast cancer.

Dr. Cecelia Bellcross is a board-certified genetics counselor, an associate professor for Emory University’s Department of Genetics, and director of their Genetic Counseling Training Program.

She says you should take every result you’re given with a grain of salt.

“If [people] are reading those results as this is for sure, 100 percent accurate prediction, and ignoring things like their family history or their lifestyle and environment, then they are getting a very skewed and inaccurate picture of their actual risk,” Dr. Bellcross said.

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Because of better technology, genetic medicine has exploded, and testing your own DNA has become quite popular.

Thanks to several direct-to-consumer kits, with a quick spit or swab, people can do it from home, but Dr. Bellcross says interpreting the results is not so easy. She says to think of it like a puzzle with a thousand pieces.

“We are trying to figure out the puzzle picture with only 50 of those puzzle pieces, so there’s a lot of missing information,” she said.

On their website, 23andMe admits they only test for certain variants in a gene. That means if you have a variant they don’t test for, you could still be at risk. It also mentions that even if the results show you’re in the clear, you could still develop the disease.

“Genetics is not a crystal ball,” Dr. Bellcross said.

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The FDA limits how much at-home kits can say, so some people have gone the extra step of sending those results to a third-party lab.

“One of the things one company does is it will sequence your entire genome, but legally it can’t interpret it. However, for not much money, you can send it to a third-party that will interpret your entire genome,” she said.

Dr. Bellcross says that’s where the real harm comes in.

“A little over a year ago, a study was released showing that 40 percent of the results coming out of that third-party lab are false positives,” she said. “An individual was told he had a presenilin one mutation, which is associated with 100 percent risk for early-onset Alzheimer’s disease, and you can imagine what getting that kind of results would mean.”

23andMe sent us this statement:

  • 23andMe is a broad screening tool for certain genetic health conditions. If an individual has a family history of a medical condition or other indications for clinical testing we always recommend consulting a health care provider first. 23andMe results can and do facilitate valuable conversations with health care providers. In fact we've had many cases where customers have taken a 23andMe result to their doctors, been prescribed confirmatory testing and have had preventative treatment as a result. 
  • We’ve conducted extensive user comprehension testing as part of the FDA authorization process to ensure customers understand the information we provide, including that a 0 variant (or "negative") result does not necessarily mean they're not at risk for developing a condition. 
  • Also through the FDA regulatory process, we've proven our test to be over 99% accurate as compared to Sanger sequencing, the industry gold standard, and over 99% repeatable and reproducible, per the review process. As for the health conditions we test for, 23andMe tests for predispositions of certain health conditions such as Type 2 Diabetes, Celiac Disease and Parkinson's disease. You can find a full list on our website, linked here
  • We do not share customers' data with third parties without their separate, explicit consent. Customers are in control of how their data is shared, and how their data is stored. 

Dr. Bellcross agrees there is value to these kinds of tests, especially if it encourages someone to exercise more or go see their doctor.

“I’m not saying there is no value whatsoever to these tests, but they have to be taken very much in context to their limitations,” she said. “To me, the better impact is someone taking a look at their health and taking that into their doctor who then can say, ‘Well you have that genetic marker, but you also have three relatives with early heart disease, and you are overweight,’ so putting it together in context.”

The last thing to consider – think about if you’re ready for whatever the test could show.

“If you find out you have a high-risk predisposition through a verified genetic test for early-onset Alzheimer’s, there’s not anything we can do about it right now, so part of the decision-making is [asking these questions]: ‘Is now a good time to know? What would I do with that information? How would I feel if I tested positive? How would I feel if I tested negative? How would I feel if I didn’t get tested?’ and processing that,” Dr. Bellcross said.

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