Genetic Fortune-Telling —Antonio Regalado

One day, babies will get DNA report cards at birth. These reports will offer predictions about their chances of suffering a heart attack or cancer or getting hooked on tobacco, and of being smarter than average.

Genetic Fortune Telling
  • BreakthroughScientists can now use your genome to predict your chances of getting heart disease or breast cancer, and even your IQ.
  • Why It MattersDNA-based predictions could be the next great public health advance, but they will increase the risks of genetic discrimination.
  • Key PlayersHelix; 23andMe; Myriad Genetics; UK Biobank; Broad Institute
  • availability now

The science making these report cards possible has suddenly arrived, thanks to huge genetic studiessome involving more than a million people.

It turns out that most common diseases and many behaviours and traits, including intelligence, are a result of not one or a few genes but many acting in concert. Using the data from large ongoing genetic studies, scientists are creating what they call “polygenic risk scores.”

Though the new DNA tests offer probabilities, not diagnoses, they could greatly benefit medicine. For example, if women at high risk for breast cancer got more mammograms and those at low risk got fewer, those exams might catch more real cancers and set off fewer false alarms.

Pharmaceutical companies can also use the scores in clinical trials of preventive drugs for such illnesses as Alzheimer’s or heart disease. By picking volunteers who are more likely to get sick, they can more accurately test how well the drugs work.

The trouble is, the predictions are far from perfect. Who wants to know they might develop Alzheimer’s? What if someone with a low-risk score for cancer puts off being screened, and then develops cancer anyway?

Polygenic scores are also controversial because they can predict any trait, not only diseases. For instance, they can now forecast about 10 percent of a person’s performance on IQ tests. As the scores improve, it’s likely that DNA IQ predictions will become routinely available. But how will parents and educators use that information?

To behavioural geneticist Eric ­Turk­heimer, the chance that genetic data will be used for both good and bad is what makes the new technology “simultaneously exciting and alarming.” 

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