Publicly available DNA tests from Navigenics and 23andMe intended to help consumers uncover genetic predispositions for diseases disagreed one-third of the time in tests on five people. The tests covered 13 diseases.
Early human-genome mapper J. Craig Venter and colleagues find in a Nature opinion article that the accuracy of the raw data is high: genotypes of an individual's markers from the two companies agreed more than 99 percent of the time. The discrepancies in disease-risk predictions, however, may be traced back to the set of markers that each service chooses to use in calculating relative risk.
The authors offer recommendations to improve predictions, including reporting of the genetic contribution for the markers tested, monitoring behavioral outcomes, and opting for sequencing rather than genotyping.
In an editorial, Nature argues that genetic-testing regulation lags behind the growing market for DNA analyses to determine consumers' ancestry or susceptibility to disease, and that existing guiding principles don't go far enough. "The value of these tests remains debatable," the editorial says. "DNA-test providers should up their game by providing only clinically useful information and spelling out exactly how much biology remains unknown."