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The scope of genome-informed medicine is vast. Alan Guttmacher, former acting director of the National Human Genome Research Institute, noted at a 2009 Institute of Medicine meeting that all current drugs, including over-the-counter, prescription, and street drugs, target only 500 or so of our genes. That’s maybe 2.5 percent of the entire human genome. It may be that only half of our genes are druggable, but that leaves huge scope for new disease treatments targeted at specific genes.
Can people be trusted with their own genetic information?
The field of genetic testing has already attracted some charlatans. In 2006, for example, the Government Accountability Office (GAO) investigated the claims being made by a number of “nutrigenetic testing” companies that promised to give customers dietary advice tailored to their genetic proclivities and sell them “personalized” supplements. According to the GAO report, “The results from all the tests GAO purchased mis-lead consumers by making predictions that are medically unproven and so ambiguous that they do not provide meaningful information to consumers.”
People and companies peddling fraudulent information of any sort should be prosecuted. But government’s criticism extends beyond such chicanery. In July the GAO reported on another sting of genetic testing companies, including 23andMe and Pathway Genomics. The GAO declared that the results of genetic screening tests were “misleading and of little or no practical use.” The chief basis for this conclusion was that the GAO’s investigators sent the same genetic samples from five people to all four screening companies and were surprised that the results were not identical.
The results differed, however, largely because each of the screening companies selects the markers it considers most relevant and the studies it deems most illuminating. That’s why 23andMe and Pathway Genomics disagreed about my risk for heart attack. But is the information offered by the main genotype screening companies accurate and valid?
Yes, it is. “I ran an analysis on personal genome results obtained from 23andMe and DeCODE for me,” says the Princeton biologist Lee Silver. “There were about 300,000 data points that overlapped between the two tests. There was not a single data point (among 300,000) that was scored positive in one test and negative in the other.”
Nevertheless, genetic information is complicated; many customers are likely to misunderstand some of it. For some bioethicists, the solution is to keep consumers ignorant by banning or at least strictly regulating access to genetic tests. Hank Greely, director of Stanford’s Center for Law and the Biosciences, told The Washington Post in May that offering Pathway Genomics tests on drugstore shelves is “reckless.” While “information is powerful,” he said, “misunderstood information can be powerfully bad.”
But how big is that risk? A 2009 study led by Colleen McBride of the National Human Genome Research Institute evaluated the responses of patients who accepted an offer for genetic susceptibility testing for eight different conditions. The results were reassuring: “We found no evidence that those who considered or sought testing were inclined to overestimate the contributions of genetics to common health conditions or to underestimate behavioral risk factors.” There was a bonus: Many people whose tests suggested they were at higher risk for some diseases were motivated to engage in healthier activities, such as losing weight and exercising more.
People can misunderstand new information. But the way that consumers learn how to use any new product is by trying it out. If the first purchasers of the new Pathway Genomics tests find them confusing or not very useful, they will tell their friends and neighbors, and Walgreens will find some new vitamin mixture or cosmetic to take up that shelf space. Instead of trying to slow down social learning about genomics, we should let companies and consumers interact so they both can learn how better to explain and understand the information such testing provides.
Gene screening may not be for everybody right now, but I am confident most people will find it useful and even entertaining sooner rather than later. Before the end of this decade, if federal regulators stay out of the way, advances in personal genomics will bring enormous health benefits to the public. More medications will be targeted to the specific genetic makeup of individual patients, improving the chances of a cure while minimizing debilitating side effects.
Already cancer treatments are being honed using genetic tests of individual patients’ tumors. For example, patients who score low on the Oncotype DX genetic test for breast cancer recurrence can avoid the physically brutal consequences of traditional post-surgical chemotherapy. Researchers are working on wide-spectrum tests that could identify the genetic signatures of diseases in patients before they are manifest. Other tests will warn prospective parents of possible deleterious gene combinations in their future progeny. The ongoing exponential growth in our genetic knowledge may even uncover ways to retard the aging process.
We are in the Apple II era of genetic testing. It would have been silly to ban the Apple II just because it was not as easy to use or immediately comprehensible as the MacBook Air. Standardization of test results will come as information accumulates about the interaction between genetic variants and environmental influences. The current tests function as practice runs for curious consumers. As one of those early adopters, I don’t want or need federal regulators to protect me from my own test results. There are things I want to keep private, but my genes aren’t one of them, no matter what they may reveal about my intelligence and genitals.
Ronald Bailey (firstname.lastname@example.org) is reason's science correspondent.