Tests like 23andMe were revolutionary 10 years ago. But their ability to predict risks of developing specific diseases have not always been very accurate, except for carrier status. Things are evolving fast now that millions of individuals have been sequenced specifically to find new genes involved in diseases. DNA tests can now (or soon) predict not only if someone will develop a medical condition, but also around what age based on their lifestyle.

MIT Technology Review: Forecasts of genetic fate just got a lot more accurate

"Last year Anders Dale, a brain researcher at the University of California, San Diego, announced his intention to market a risk calculator for Alzheimer’s disease. It will guess whether a person will develop the disease and, if so, at what age.

The service won’t launch until this summer, but Dale says drug companies immediately got in touch. Now he is helping three of them test the DNA of people in clinical trials for Alzheimer’s drugs (he declined to name them). Despite the billions spent developing such drugs, every one tried so far has flopped. The problem is that when no one knows who will get the disease, it’s difficult to know whether a preventive drug is working. If companies could test the drugs only on people with a high risk of Alzheimer’s, it would be much easier. It’s possible future drugs will be labeled “Recommended for those with polygenic scores 90 and above.”


Other doctors believe risk scores will give people the push they need to think harder about their well-being. “I love the idea of polygenic risk scores because the future is health, not medicine,” says Steven Tucker, a physician who practices in Singapore. He likes his patients to use wearable devices and trackers, and risk scores could be combined with those. Someone at high risk for atrial fibrillation, for instance, might wear a smart watch with a heart monitor built into it. “My patients want to manage the future,” says Tucker. “If you can define it more accurately, there is a better chance you can do something about it.”

Beyond medicine, DNA tests are also getting more accurate at predicting traits. It's now possible to determine someone's height within 4 cm, an amazing feat considering that many people are considerably taller than their parents (sometimes by more than 10 cm). Predicting someone's genetic intelligence remains controversial.

"In addition to predicting disease, geneticists can build models to predict any human trait that can be measured, including behaviors. Is this person destined for a life of crime and recidivism? Will that one be neurotic, depressed, or smarter than average?

The scoring technology, scientists say, will soon shed uncomfortable light on such questions. In January, two leading psychologists argued that direct-to-consumer DNA IQ tests will soon become “routinely available” and will predict children’s ability “to learn, reason, and solve problems.” They believe parents will test toddlers and use the results to make school plans.

To some, using foggy genetic horoscopes to decide who goes to college and who ends up in trade school sounds like an extraordinarily bad idea. On his blog Gloomy Prospect, Eric Turkheimer, a prominent psychologist at the University of Virginia, says the danger is that the scores will be overinterpreted to “recommend some truly dreadful social policies.” That, he thinks, would be “the worst possible kind of biologically determinist discrimination.” To Turkheimer, polygenic scores are “less than meets the eye” and about as fair as “predicting your IQ from a cousin you haven’t met.” Such views aren’t stopping the rapid pace of genetic exploration. Until last year, no gene variant had ever been tied directly to IQ test results. Since then, studies involving more than 300,000 people’s DNA have linked 206 variants to intelligence. It means genetic scores can now account for 10 percent of a person’s performance on an IQ test. That could reach 25 percent within a few years, as more data accumulates.