The Globe and Mail
February 17, 2011
It was billed as one of the pivotal moments in the history of medicine. A decade ago this month, researchers published their long-awaited results of deciphering the human genome – providing the genetic blueprint of our species.
Many experts claimed the new knowledge would spark a genetic revolution. They said doctors would soon be able to accurately predict who among their patients was most at risk of developing certain diseases. And patients, in turn, would be able to take corrective action – either by adjusting their behaviour or using new gene-based therapies.
But a retrospective paper, which will be published Friday in the journal Science, points out the “revolution” has not lived up to expectations – at least not yet.
The article, “Deflating the Genomic Bubble,” was penned by geneticist James Evans of the University of North Carolina, bioethicist Eric Meslin of Indiana University, psychologist Theresa Marteau of King’s College London and law professor Timothy Caulfield of the University of Alberta.
“The predictive value of so much of this genetic risk information is really quite low,” Prof. Caulfield said in an interview. “It has proven to be far more complex and far more nuanced than imagined.”
Or, simply put, just because you are born with a certain group of genes, it doesn’t mean you are going to get a particular disease or steer clear of it either.
Dr. Evans said it was naive to assume that genes would provide a crystal-ball view into a person’s future, “because common diseases have many causes and genetics is only one factor.”
He added that it was equally naive to assume that people would adjust their behaviour – like eating a healthier diet or quitting smoking – when genetic tests implied they were at risk of an early death if they didn’t mend their ways.
Another disappointment is that there has not been the anticipated flood of new therapies spilling forth from the $3-billion (U.S.) that is spent annually on genetic research worldwide.
Dr. Evans and his co-authors still have high hopes for the field. “We don’t want to trash genomics.” In fact, they say, there have been a few major discoveries that have profoundly affected the lives of some individuals. Women born with mutations in the so-called BRCA1 and BRCA2 genes face an 85-per-cent lifetime risk of getting breast cancer. And genetic tests can now help determine who will benefit most from certain cancer therapies.
But, he said, those specific examples are the exceptions rather than the rule. For the most part, the true promise of genomics lies in its ability to lay bare the mechanisms of disease. “That will ultimately have great payoff in human health. It is just going to take a long time,” Dr. Evan said.
Meanwhile, inflated claims of immediate genomic benefits could threaten the long-term credibility
of the field. To make matters worse, an over-emphasis on genes “may also distract our gaze from other promising approaches to preventing disease and improving health,” the authors warn in the article.
“Our argument is that we are not doing the field of genetics any favours if we unrealistically hype its promise,” said Dr. Evans. “Indeed, by doing so, we risk a backlash that will set the field back.”