Direct-to-consumer genetic testing kits vary in predictions of disease risk

(Medical Xpress)—An in-depth analysis and comparison study conducted by investigators at Emory's Rollins School of Public Health demonstrated variations in predicted disease risks by companies that offer direct-to-consumer personal genome testing.

Led by Cecile Janssens, PhD, research professor of Epidemiology, the team investigated DNA test results from three "direct- to-consumer" genome testing companies (23andMe, deCODEme, and Navigenics) to assess and compare their predictive abilities. Results show that predicted risks differed among the companies and were contradictory for certain traits in certain individuals.

The complete findings are available in the online edition of Genetics in Medicine.

"Although two of the companies that we studied are no longer operating, and sequencing is becoming less expensive and testing such as this is increasingly popular," explains Janssens. "The methods used for predicting these types of results are of important concern."

Test results provided by the three companies indicated an individual's risks for a large number of diseases. The study was conducted by creating DNA data for a hypothetical population of 100,000 individuals which is a less expensive and equally valid method for demonstrating the variations in predicted risk among the companies.

Predicted risks were calculated using the prediction methods of the three companies, obtained from their websites. Predicted risks were assessed and compared for six diseases: , prostate cancer, , Crohn disease, age-related , and .

The variations in predicted risks were explained by three factors:

  • The companies considered a different number of genetic variants in the risk calculations. Generally a larger difference in the number of variants implied more variation in predicted risks.
  • All three companies used an estimate for the average population disease risk as a starting point for their predictions. Differences in average risks affect predicted risks of all consumers to the same extent. For example, when the average odds is two times higher, all predicted odds are also two times higher.
  • The companies applied different mathematical formulas. The formulas of two companies led to an overestimation of risks when predicted risks were higher and even predicted risks that were higher than 100 percent.

"Our study provides insight into the methodology and performance of risk estimation for personal genome tests," Janssens explains. "Future efforts to design predictive models will benefit from understanding the strengths and limitations of these current models and formulas."

More information: www.nature.com/gim/journal/vao… full/gim201380a.html

Related Stories

Genetic testing kits get closer look in Loyola study

Jul 15, 2013

(Medical Xpress)—Several companies sell genetic testing directly to consumers, but little research has been done on how consumers experience such tests. The tests have raised questions about the validity and accuracy of ...

Are we selling personalized medicine before its time?

Feb 06, 2009

We may be a long way off from using genetics to reliably gauge our risks for specific diseases, say researchers at the University of Pittsburgh Graduate School of Public Health in a study published on Feb. 5 in the online ...

Recommended for you

Science of romantic relationships includes gene factor

Nov 23, 2014

(Medical Xpress)—Adolescents worry about passing tests, winning games, lost phones, fractured bones—and whether or not they will ever really fall in love. Three Chinese researchers have focused on that ...

Stress reaction may be in your dad's DNA, study finds

Nov 21, 2014

Stress in this generation could mean resilience in the next, a new study suggests. Male mice subjected to unpredictable stressors produced offspring that showed more flexible coping strategies when under ...

More genetic clues found in a severe food allergy

Nov 21, 2014

Scientists have identified four new genes associated with the severe food allergy eosinophilic esophagitis (EoE). Because the genes appear to have roles in other allergic diseases and in inflammation, the ...

Brain-dwelling worm in UK man's head sequenced

Nov 20, 2014

For the first time, the genome of a rarely seen tapeworm has been sequenced. The genetic information of this invasive parasite, which lived for four years in a UK resident's brain, offers new opportunities ...

User comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.