IntroductionPaul Griffiths considers the issue of direct-to-consumer genetic testing
"The availability of direct-to-consumer genetic tests has increased dramatically over the last ten years and needs to come under general guidelines" according to the Human Genetics Commission (HGC) which this week launched its Consultation on a Common Framework of Principles.
Egenis Visiting Professor Paul Griffiths considers the issue of direct-to-consumer tests in an article in the autumn edition of the gen, the EGN newsletter. The newsletter will be available online shortly, but you can read Prof Griffiths' article below.
Consumer Genetics: Mendel in the Big Brother House
The concerns of regulators and social scientists are unlikely to have much impact on the rise of consumer genetics. Direct to consumer genetic testing, or ‘consumer genetics’ as some advocates prefer, allows the consumer to deal directly with the laboratory - supplying the sample and receiving the result. The consumer does not have to be sick, nor need they be referred by their general practitioner. Consumer genetics construed more broadly might include tests initiated by the consumer but where the results are delivered to their doctor, like the now discontinued GRK3 test for bipolar disorder from California-based Psynomics Inc, and advertising directly to the consumer tests which they can access through their GP.
A wide range of tests are now available to consumers. Paternity testing is the best known form of family relationship testing, but there are many more. In many countries, for example, genetic tests are accepted by the courts as evidence of family relationship for immigration purposes. In Australia, consumers can test their sporting ability, or that of their children with the ACTN3 ‘sports gene’ aptitude test supplied by Melbourne-based Genetic Technologies Ltd. But most attention focuses on health-related testing. Diagnostic tests for serious medical conditions and powerful predictive tests for disorders where specific mutations confer high risk are normally not generally offered directly to consumers. Consumer genetics companies focus on testing for small increases or decreases of risk for developing common health problems, such as cardio-vascular disease. Even these tests are not marketed so much for predicting disease as for indicating where the consumer should focus their efforts at healthy living. This ‘lifestyle genetics’ is presented as a form of personal empowerment, providing information which “helps you understand what your genes have to say about the future of your health, and gives you action steps to take control of your health today - so you can have a healthier tomorrow.” (http://www.navigenics.com).
Can consumer genetics actually lead us to a healthier tomorrow? There are good grounds for scepticism. The value of genetic tests is commonly assessed against the four ‘ACCE’ criteria. A is for Analytic. An analytically valid test reliably detects a DNA variation, and most lifestyle tests are analytically valid. Lifestyle testing is mostly SNiP detection (single nucleotide polymorphisms), now an unproblematic activity for any competent lab. The second criterion is Clinical validity – does this DNA variation provide reliable information about health outcomes? According to one recent assessment of the evidence base: “Our review of meta-analyses found significant associations with disease risk for fewer than half of the 56 genes that are tested in commercially available genomic profiles. Various polymorphisms of these genes were associated with risk for 28 different disorders. Many of these disorders were unrelated to the ostensible target condition, and the associations were generally modest.” 1
The third criterion is Clinical utility, which the tests also usually lack. Even if we assume that the associations on which they are based are real, they involve quite small odds ratios (the ratio between risk of the disorder in the general population and risk in a group with a particular genetic variant), typically between 1.0 (no increased risk) and 1.5. For comparison the odds ratio for smoking and lung cancer is close to 20.0. Since genomic profiles include both risk factors and protective factors, testing more loci does not lead to larger departures from the risk in the general population. So whether classified by their genomic profile as ‘high risk’, ‘normal risk’ or ‘low risk’ for common diseases, the recipients of these results are in fact close to the level of risk in the general population and would all be well-advised to follow standard public health recommendations.
Then final letter in ACCE stands for Ethical, Legal and Social Implications (ELSI). Information papers issued by government agencies and the social science literature have each raised ELSI concerns about direct to consumer testing. However, there seems to be an emerging consensus that formal regulation of lifestyle genetic testing is neither practicable nor ethically desirable. It is impractical because testing is not nationally based and involves untraceable sample collection procedures, such as 23andMe’s mail order saliva sample kit (Time magazine’s 2008 invention of the year!).
The ethical argument against regulation has two strands. The first is a libertarian one: “if individuals wish to explore their own genome, then it is their information to explore and no government or medical body has a right to deny them access.”2 This argument is made in the broader context of the rhetoric of the internet age. 23andMe is a private company co-founded by Anne Wojcicki, wife of one of the founders of Google. Customers are invited to monitor regularly their changing risk profile online as new studies are factored in, and to join online communities where they can interact with individuals with a similar genetic profile. In this context, restricting access to genetic testing seems as passé as objecting to your house appearing on Google Street View.
Complementing the libertarian argument is the claim that lifestyle genetics creates no substantive harms to justify restricting consumer choice. These are weakly predictive tests. Learning that you have a slightly higher risk of Type II diabetes than the population average is probably less traumatic than viewing public health advertising, especially if you are a smoker or a drug user. There are some obvious replies to this argument. Genetic tests for mental illness may have a much greater personal impact than those for other illnesses. This is a question which requires attention from social scientists. Moreover, it is easy to obtain DNA from someone else and send it to a direct to consumer service, with obvious potential for harm, although obtaining a DNA sample without consent has been specifically legislated against in the UK and probably soon will be in Australia.
One pattern that is becoming apparent is that consumer genetics companies will adjust their practices so as to avoid triggering formal regulation.3 Some go to great lengths to state that their tests are not diagnostic tests, and that they are not predicting illness. The distinction that exists today between the pharmaceutical industry on one hand and the cosmetics and nutritional supplement industries on the other may also develop in genetic testing. Just as a ‘DNA-based’ cosmetic is likely to have a ‘no biological effect’ disclaimer tucked away somewhere, future genetic tests, albeit presented as the key to your future health, may have in very small print ‘for entertainment only’.
1 Janssens, A.C.J.W., et al., A Critical Appraisal of the Scientific Basis of Commercial Genomic Profiles Used to Assess Health Risks and Personalize Health Interventions. American Journal of Human Genetics, 2008. 82(March): p. 593–599.2 Anon, In need of counseling? Nature Biotechnology, 2008. 26(7): p. 716.3 Saukko, P., Pitching products, pitching ethics: Selling nutrigenetic tests as lifestyle or medicine, in Nutrition and Genomics: Issues of Ethics, Law, Regulation and Communication, D. Castle and N. Ries, Editors. 2009, Elsevier Science. p. 205-222.