Direct-to-consumer genetic testing is pilloried but pushes back. Gene regulation, pro and con. Why cystic fibrosis is not a WASP disease and other genetic errors.
[We have an RSS feed. No orange icon, but click here. If that doesn't work, the URL is http://www.nasw.org/rss.xml]
CONSUMING GENETIC TESTING. The controversies about direct-to-consumer genetic testing are heating up for real, thanks to a semi-shocking report the Government Accountability Office released last week. Get details from two Singers, Natasha at the New York Times's Prescriptions blog and Emily at Technology Review..
The report documents that customers of the testing companies would likely get conflicting reports on their gene-based risks for disease depending on which company they patronized and what data each company was basing its findings on. Which, if you've been paying attention to this increasingly fashionable consumer pastime at all, is probably not news to you. (For data on the public embrace of genetic testing, see Bertalan Mesko's recent post at ScienceRoll. In just 10 years, the number of sequenced personal genomes is projected to grow to 25 million from about 1000 this year.)
GAO also showed some companies engaging in marketing practices that are outright deceptive, complete with videos of the agency's sting operations. The report was followed immediately by a congressional hearing featuring Henry Waxman and his patented expressions of high dudgeon. (This is not a complaint; the country needs regular infusions of the Waxman waxing wroth.)
DTC GENETIC TESTING TAKES OFFENSE. What has been particularly interesting, though, is the amount of pushback to the report and the hearing. 23andMe, perhaps the most prominent DTC genetic testing company, posted a long unsigned critique on its blog. The company castigated the report as being "unscientific," which is perfectly true, as the report noted itself. (Aside: The precious bodily fluid that the consumer provides to 23andMe for testing is saliva, so the blog is called The Spittoon. It gets extra credit for its glorious slogan: "more than you've come to expectorate.")
Not all the testy responses came from genetic testers. Or even folks with obvious industry ties. Daniel MacArthur at Genetic Futures, a blog that largely favors genetic testing, called the hearing
a vicious, one-sided affair, starring a biased report on a "sting" operation performed by the US Government Accountability Office. Along with other recent moves by the FDA, it potentially sets the scene for draconian regulation to be laid down on the industry.
The Food and Drug Administration is said to be considering regulating DTC genetic tests as medical devices. MacArthur opposes FDA regulation but does call for more transparency, in the form of
creating a mandatory database of genetic testing products containing information about the scientific basis of companies' claims - preferably by building on the NIH's proposed Genetic Testing Registry - [which] would provide a platform for consumers to make an informed comparison of reputable tests. It would also provide an even playing field for public critiques of the markers and algorithms used by each company, spurring the industry as a whole towards improving their products.
MacArthur also contributes to Genomes Unzipped, a group blog about the DTC genome testing industry, where the opinions are more diverse. This week, prompted no doubt by the GAO report, the posts have mostly been about regulation and potential regulation of this young industry. On the other side, "If you're predicting disease, you should be regulated," say Jeff Barrett and Katherine Morley, who are statistical geneticists (or maybe one should say genetic statisticians?)
Mike the Mad Biologist concurs that
First, the DTC industry has to realize that they are in the medical testing device business. Like it or not, once they moved beyond vanity genomes for rich or well-connected white guys, and started to make medical claims, well, that makes genetic testing a diagnostic device.
He recommends a structure similar to the one set up for assessing antibiotic resistance in disease organisms.
I came away from Gene Expression not at all sure of Razib Khan's position. He says he favors "light" regulation and notes "that fraud, error and misrepresentation are rife across many health-related sectors in American society." He then observes:
I don't think that the fraud and misrepresentation one can find in DTC personal genomics is exceptionally worrisome or notable to warrant such attention or focus. This is an inefficient allocation of concern and regulatory resources, driven more by the industry's puffed up claims and the apocalyptic projections of the skeptics.
Does he mean that genetic testers should be permitted puffed-up claims? That it's ok to sell people nutritional supplements they have been told are designed specifically for their genes? That's not puffery, that's a lie.
Khan also drops this bomb, which I include because it's useful, if startling, to learn what others are saying about our profession, even about publications that generally practice a pretty high level of medical journalism:
Bad journalism on the health beat causes way more suffering than DTC genomics kits ever will, as people who are not intelligent make precipitous decisions based on the latest result which managed to slip through the p-value gauntlet and are sexy enough to be written up in USA Today.
WHY CYSTIC FIBROSIS IS NOT REALLY A WASP DISEASE. If you can read just one thing on this topic, make it Ed Yong's post at Not Exactly Rocket Science describing his experience with genome testing. Yong is nearly always worth reading, this whole post more than most.
On one particular point this post was for me specially instructive. I suspect Yong's experience with testing is probably about average: "fun but a little disappointing" is how he described it. But here's the instructive part. In describing one of his results, he made a mistake. He said results showed he ran no risk of fathering a child with cystic fibrosis.
A couple of commenters pointed out the error. Most cases of cystic fibrosis are due to a particular mutation in the gene for cystic fibrosis transmembrane conductance regulator (CFTR), an ion channel. So if you don't have that specific mutation, there's quite a good chance that you won't have a baby with CF.
But it's not a perfect chance. That's because there are many other mutations — more than a thousand of them are now known — that can lead to CF. Each one is quite rare individually, but the fact that they exist out there in the population means that, in the absence of perfect tests for them all, none of us can say "My potential children are 100% safe from CF."
In haste I declare that I am not teasing Yong for this small mistake, and the fact that he made it is not why the post was instructive for me. What was instructive is that when I read the post, I made exactly the same mistake. I said to myself, "Of course no CF; CF is a WASP disease." I didn't realize my mistake until I got to the corrective comments.
To compound my embarrassment, I knew better. Years ago I wrote a thing about how variability in CF mutations was creating occasional problems in genetic counseling. (At that time only about 100 of those rare mutations had been identified; now there are 10 times as many.) I had simply forgotten about that variability. What came back to me is what I learned in grad school back in the last century, before anyone knew about the CFTR gene: cystic fibrosis is a WASP disease. The truth is that CF is only mostly a WASP disease.
My point being that the problem with DTC genetic testing is not, as Razib Khan would have it, that "people who are not intelligent" make wrong medical decisions on the basis of incomplete and incorrect information. The problem is that information about this stuff changes constantly and is so complex that even people who are intelligent (moi) and — more important — reasonably well schooled in genetics (moi aussi) can't possibly hold it all in their heads all the time.
When you add to the native complexity of genes the almost incomprehensible complexity of gene regulation — well. The mind reels. The multitude of mechanisms controlling gene behavior, known as epigenetics, begins to make your genes themselves seem almost irrelevant. DTC genetic testing may foster the quite erroneous notion that a particular gene (or a particular mutation) will lead to a particular outcome. What really matters is what the world does to your genes — what turns them on and off, and how, and in what cells, and at what time in life.
That's hyperbole, but not much. I don't know where that leaves us with respect to DTC genetic testing. At least with some sort of oversight, I hope, and an end to the preposterous claims that nutritional supplements can be specially tailored to your personal genome.
