Wednesday, November 10, 2010

GWAS, hype and cashing in -- DTC genetic testing

In our opinion, the problems with direct-to-consumer (DTC) genetic testing has never been so accurately described as it is by Murray et al. in the latest issue of Trends in Genetics (well, except maybe when we did it here).
 Among the estimated 480 different traits covered in the collective offerings of current DTC genetic-testing companies there are tests for the creative, musical, linguistic, and shyness ‘genes’, as well as for intelligence, athletic aptitude, and bad behavior.One company promotes a testing package for ‘inborn talent’ as the ‘result of the Human Genome Project’ ( Other companies use ‘proprietary technology’ to offer personalized nutritional products based on genetic testing ( Often without citing a single DNA variant or gene, companies promote their products under the protective cloak of legitimate science.
The authors provide a number of examples of tests these companies offer for genetic susceptibility to traits like athletic ability or 'avoidance of error' based on data from small studies or results that haven't been replicated.  They do say that the quality of supporting scientific evidence offered varies by company, with some being at least more formally careful than others to tell their customers that the evidence isn't strong.  But Murray et al. rightly point out that to offer the tests at all, under the guise of scientific authority, is misleading and wrong.
Why are these tests being put on the market at all? Their very offering with the accompanying ‘information’ implies that the test results are meaningful, and thus misrepresents how the scientific community comes to accept conclusions as valid.
They go on to say that scientists publishing new genetic findings have the responsibility to publicly and pre-emptively state that their results are not definitive, and are not for commercial use.  Editorial writers for journals should point out the same thing when they highlight these kinds of results.  The distortion (their word) of science in the way that the DTC companies offer should be countered by "active engagement of the public by scientists in a way that both informs and encourages debate over the social consequences of new scientific findings".

We heartily agree.  Even when a company posts some quality evaluation of studies they cite, as if they're informing the customer, they know very well what the impression of the customer  will be.  If the studies are weak, an honorable company would not do the test (and reduce costs and claims accordingly).

The issue of FDA oversight of these companies has gotten a lot more play than the question of whether they are offering anything of actual value to the consumer, or the extent to which this is just a new version of snake-oil salesmen.  These companies are often, perhaps largely using results from GWAS and other similar kinds of studies, that by now every candid person knows have not delivered nearly the promised goods in regard to clearly causal, reliable, risk-estimable results.

Of course, some alleles can be tested for and have high predictive power, but those can, and often if not usually have, been the purview of legitimate genetic counseling services.  And most people who use the services out of the blue won't have such alleles, or they or their family would already have the condition, if the allele is due to a reliably predictive allele.  If they do, they should already be under the care of a specialist clinic.  And recessive traits involve mates not just individual customers, and are generally much trickier to understand from DNA sequence data.  And a negative DTC result does not mean a clean bill of health, for too many reasons to go into here.

This is all if we're talking disease.  If we're talking designer children and whether to make your kid practice his/her football or violin, who knows?  Or deciding how you should vote  based on your genotype.  What unconstrained kinds of nonsense are afoot!

Of course the companies want to stay in business (is it fair to say 'cash in' while they can?)  but there is probably, for some at least, a more than trivial objective of doing good for customers.  But the overall industry doesn't seem much like a responsible, ethical endeavor.  Some of the scientists involved in the best companies know very well what they are doing. 

At the very least, as in any technical industry in which consumers have no way at all to defend themselves adequately, we need strong evidence-based regulation of this industry.  Otherwise it will cost the health care system enormous amounts of money chasing down false signals, will provide fodder for all sorts of malpractice suits, and in doing so will show that culpably casual acceptance and promotion of GWAS-like studies that promise 'personalized genomic medicine' have been damaging rather than benefiting to public health.  Casual hype is not idle play, and is short-term gain for a few with long term costs for many.

The recent studies claiming that, in a contorted way, a genetic variant determines how you vote, and some of the 'talent' claims of DTC companies that we mentioned above, have more than a little whiff of similarity to the same kinds of claims made, starting with Darwin and through the eugenics movement up to World War II.   Triggered by the 'liberal gene' study, we have promised to expound on that and other fashionable social-behavior genetics and we'll do it, but we've been too busy this week and last.

Even if nobody in the DTC companies has a new eugenics or a new round of social Darwnism in mind, the potential for their hyped promotion of genetic determinism to be used for corporate or government policy, with potential societal abuse, is obvious.  Dismissing DTC as a fad is playing with matches.

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