Study: DNA sequencing dubious as disease prevention tool

DNA sequencing may not be so useful after all for determining future health risks and ways to prevent them, according to a new Johns Hopkins University study.

Using a mathematical model based on studying genomic registry data from twins, they determined that patients whose DNA was known to them or healthcare providers were just as likely as patients without DNA sequencing to succumb to a number of different diseases.

Many have predicted that the process of mapping a person's DNA would be crucial to predicting what future diseases are coming, or might come, your way. But the finding, after a massive analysis of data from international genomic registries involving more than 53,666 identical twins, puts that theory into the realm of doubt. This is big news, to the point that The New York Times, Associated Press and many other publications have highlighted the research. Details are published in the journal Science Translational Medicine.

As The New York Times explains, the research team led by Dr. Bert Vogelstein analyzed identical twin genomic data looking at how often each twin either ended up with or didn't end up with 24 different diseases. They realized that figuring out the likelihood of a disease didn't prevent it from coming anyway, even if the risk was low. They determined, for example, that more than 93% of women in the study had a minimal breast cancer risk, but they could still come down with the cancer.

It's not all bad. The article notes, for example, that as many as 90% of people with DNA sequencing could determine that they are at high risk of coming down with at least one disease. And gene sequencing is also useful for identifying conditions like heart disease and Alzheimer's disease, zeroing in on up to 75% of patients who will develop those diseases down the line. But even those benefits are dubious, the story argues, because while you can treat heart disease, conditions like Alzheimer's are--at this point at least--inevitable, if you are genetically predisposed to developing them. Take ovarian cancer, for example--a person at high risk isn't necessarily going to get it, based on their data evaluation.

Of course, some physicians insist DNA sequencing remains useful and argue that sequencing can still be a valuable tool, The New York Times notes, such as helping to determine a patient's chance for recovery, or even helping doctors assign drugs to specific patients to help prevent heart disease down the line.

- here's the NYT story
- read the Associated Press piece, via USA Today
- consider ABC News' coverage
- check out the journal abstract