Navigating “The Wild West” Marketplace of Consumer Genetic Testing–and Other Needed Information About Our DNA

In an article in The New York Times Sunday Review, genetics counselor Laura Hercher described a man named Matthew Fender, who—after searching for heredity data through 23andMe—had placed his genetic test results into Promethease, a DNA search engine that probes such data for variants cited in the medical literature.  Fender had sought to learn his risk for developing a pulmonary embolism, the condition that had killed his sister, a seemingly healthy young woman of 23. The report didn’t mention that, but it did provide the alarming news that he carried a mutation (PSEN1) strongly associated with early onset Alzheimer’s, as well as two copies of a gene variant (ApoE4) that indicates greatly increased chances of developing late-onset Alzheimer’s. After getting no satisfactory guidance from his primary care doctor and other professionals, Fender checked out a competing genetics company, Ancestry DNA,  to see what his results there would say about the PSEN1 variant. They said nothing. He then persuaded his doctor to order the test, which proved negative.... It’s worth noting that both companies claimed their tests were 99.9% accurate. Yet a 23andMe representative told Hercher that “a 99.9% accuracy can still mean errors.”