They calculate that for 23 of the 24 diseases examined, most people who have their genome sequenced will receive negative results—that is, their genome sequence will show no increased risk for a disease such as diabetes as compared to the general population. That negative answer, however, is not a free pass—it would simply mean that person had nearly the same chance of developing the disease as the rest of the population.
Nonetheless, for more than 90 percent of people who’ve had their genome sequenced, the information may alert them to an increased risk for at least one of the 24 diseases examined, and thus could make them more proactive about fighting it.
For some experts, the estimates bring a much-needed reality check. “Genomics is going to be very valuable, and it has already proven very valuable to some patients, but whole-genome sequencing and the like will not be a panacea or a magic bullet for everybody out there, especially with regard to common disease,” says James Evans, a clinical cancer geneticist at the University of North Carolina at Chapel Hill School of Medicine. “In the end, we all pay for each other’s medical care, either because we are in an insurance plan or we are in Medicare, so it’s in nobody’s interest to indiscriminately apply technology and new modalities to people who don’t need them and won’t benefit from them.”
Yet other experts say the study shows only what we already knew. No one trying to translate clinical genomics into clinical practice is using prediction of risk for common disease traits, because it doesn’t work, says James Lupski, clinical geneticist at Baylor College of Medicine. However, with less common syndromes with clear genetic causes, defining the genes involved and identifying them in diagnosis is extremely powerful, says Lupski. “I don’t want people throwing out the baby with the bathwater.”
George Church, a professor of genetics at Harvard Medical School and director of the Center for Computational Genetics, says we will save many more lives if whole-genome sequencing is done on the whole population. “Even if the majority of individuals will receive negative test results, you don’t know until you check,” said Church by e-mail. “It is analogous to fire insurance; you don’t know in advance if you are in the majority who will not lose their house.”