UMN Expert: Consumer genetic testing

July 26, 2018
Heather Zierhut

More than 12 million people have taken an at-home, direct-to-consumer genetic testing kit. An increased demand for personalized medicines ensures the genetic testing market will continue to grow. Consumers take these tests for a variety of reasons, from learning about their ancestry to discovering if they possess genes linked to specific diseases.

Whatever a person’s reason is, Heather Zierhut, Ph.D., assistant professor and associate director of the Genetic Counseling Graduate Program, explains there are some things to consider before taking a genetic test — specifically, an at-home test.

Heather Zierhut, Ph.D.
"The first thing to consider is that most consumer genetic tests do not look at the whole genome. Right now, most consumer DNA tests look at only about million of a person’s three million nucleotide pairs. That’s two-thirds of our genetic information that doesn’t even get looked at. It’s possible that scope could broaden in the future, but for now it is very limited.

"Not all consumer genetic testing companies are equal. Some companies use different approaches and different baseline data. That means your results — and the accuracy of them — can vary. Which test you choose should depend on what kind of information you are most interested in obtaining.

"The ability of these at-home tests to predict the chances of you developing a particular disease is complicated. Your genes are complex. In most cases, your genes are a small piece of what contributes to your risk of developing a disease. These tests do not take into account your family history, diet or other risk factors. Therefore, they generally do a poor job of testing for and estimating complicated risks.

"If you’re trying to learn more about your ancestry, it’s good to keep in mind these tests don’t get too granular. If you want to know if your family is French or German, it’s likely consumer genetic tests will tell you the percentage of your DNA that indicates you are of northwestern European descent. However, it won’t differentiate French, German or Swiss.

"If privacy is a concern, consumers should know that DNA testing companies can share and, in some cases, sell the data they collect. That means your genetic information can end up in third-party hands.”

Heather Zierhut, Ph.D., is an assistant professor in the College of Biological Sciences at the University of Minnesota. She is also the associate director of the Genetic Counseling Graduate Program, where she trains future genetic counselors and researches about the outcomes and effectiveness of genetic counseling methods currently in use.

Contact information:
Heather Zierhut
(o) 612-626-6743
zier0034@umn.edu

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