Genetic variants that are thought to be pathogenic don't always turn out to cause disease. For instance, the Boston Globe notes that Robert Green at Brigham and Women's Hospital carries a variant linked to Treacher Collins syndrome, a condition marked by facial deformities, that he doesn't have.
“Most likely this is not a meaningful mutation,” Green says. “I know this, but imagine if you’re a pregnant woman and someone reported that mutation out to you about your baby. Can you imagine?”
This and other examples, the Globe says, underscore that one's DNA doesn't predict one's future and that more work needs to be done to figure just what all these variants mean.
Part of the problem is how disease-causing or –related variants were uncovered, adds the Broad Institute's David Altshuler. "You will get the wrong answer, in a very predictable way, if you take a set of data collected in individuals with extreme, rare disease and take a person who doesn’t have any disease and try to extrapolate what their risk would be based on people who were selected precisely because of their rare disease," he says.
And then, Heidi Rehm from Partners HealthCare Laboratory for Molecular Medicine tells the Globe that different labs interpret those results differently. “There’s going to be a massive awareness of what we don’t know and the discrepancies about what people are saying about things,” she says, adding that the problems will be addressed after that happens.