Guest post: Barbara Prainsack on public attitudes to DTC genetic testing

Barbara Prainsack is senior author on a paper published last week exploring public attitudes to direct-to-consumer genetic testing. She kindly agreed to summarise the key findings of the paper for our readers.

Much has changed since the first personal genome testing (PGT) companies three launched years ago. Vivid discussions are taking place about the ethical and societal dimensions of especially the direct-to-consumer sector of PGT, and debates continue on how to regulate the field: Advisory commissions in many countries are issuing recommendations, and regulators have stepped in. In the meantime, Harvard’s Personal Genome Project (PGP) has reached over 1,000 participants, and PGT companies have dropped prices considerably and later raised them again. Of the three PGT companies (23andMe, deCODEme, Navigenics) which launched in autumn 2007, only one (23andMe) continues to sell their tests solely DTC (Navigenics offer their tests through doctors, and deCODEme do both), but numerous other companies have joined the DTC market. This shows that there is clearly an ongoing need for raising awareness and facilitating debates about personal genomics.

The launch of Genomes Unzipped (GNZ) last June, and to an even greater extent, the unzipping of the genome data of its core members, mark important steps on that road. One of the largest achievements of GNZ so far is that it has pushed the debate beyond hypothethical scenarios but enables a discussion of an actual scenario of real people publicly sharing their PGT results.

We hope that with findings from a survey published last week we can also make a small contribution to the debate. Early in 2008, our group at the Department of Twin Research and Genetic Epidemiology, and the Centre for Biomedicine & Society at King’s College London, started wondering what the potential market for such tests would be, for what reasons people would take the test, and what they would do with the results. In autumn 2008, we sent out questionnaires about PGT to 6,510 volunteers, aged 17-91, in the TwinsUK registry. 4,050 people responded to the survey, which to the best of our knowing makes ours the largest survey of public understandings of PGT so far.

The survey

In the questionnaire, PGT was presented to our participants as follows:

‘Since 2007 it has been possible to order a personal genetic screen over the internet. You send a sample of saliva to a commercial company who look at selected genetic markers. Based on these markers they estimate your personal lifetime genetic risk of developing around 20 common diseases (such as heart disease, Alzheimer’s disease, glaucoma or diabetes). Results are sent via an email alert to a private web-link.’

We found that only 13% of our respondents were even aware that PGT existed. This may be partly due to the fact that, as mentioned, the survey was carried out in autumn 2008, barely a year after the launch of the first PGT companies (deCODEme, 23andMe, and Navigenics). On the other hand, media coverage of PGT was very intense especially during the first year, rendering it likely that those with an even moderate interest in genetic testing would have heard or read about direct-to-consumer PGT by the time we sent out our questionnaires. Unsurprisingly, younger people were more likely to be aware of PGT than older people (other than age, no socio-demographic parameters were found to correlate).

Only 5% of our respondents stated that they were either ‘very likely’ or ‘fairly likely’ to take a PGT if the test cost £250 (roughly the equivalent of $400, which is a bit under the price of the health-only package of 23andMe, for example; yet tests focusing on fewer phenotypes are available for less). Respondents from lower socio-economic backgrounds were underrepresented in this group.

The percentage of those who said they were likely to order a PGT if it were available for free rose to a stunning 48%, with younger people and males being overrepresented, and those with the highest socio-economic status being underrepresented in this group.

When drawing conclusions for how this could predict actual uptake of PGT, we need to be cautious as we know that people tend to be more willing to say that they will take a test than they are willing to actually take one. However, what this relatively high number of those who are interested in free PGT does convey is that a considerable proportion of the population, at least in the UK, does not seem to be afraid of receiving their genome data – either because they would definitely want to undergo PGT and the main obstacle is affordability, or because when offered a free test they are less likely to consider the consequences.

What would they do with the test results? The vast majority (93%) of those who, in our survey, stated that they would be likely to take a PGT, would do so to encourage them to adopt a healthier lifestyle if found to be at high risk of disease (please take a look at our paper to read our discussion of the use of the phrase ‘if found to be at higher risk of disease’). 79% said that they would want the PGT to enable their doctor to monitor their health more closely, and the same proportion (80%) said they would take it to be able to convey genetic risk information to their children. Women, older people, and people with children were more likely to agree with both these statements. These reasons were the most commonly chosen ones for why people would take the test; with regard to other reasons – such as being able to better plan one’s financial future – our respondents were divided.

What are the implications of these findings? A key finding here seems to be the high proportion of individuals (79%) who said that they would take the test results to their doctor. This would clearly have consequences for health care systems. As professional and advisory bodies in several countries have pointed out in recent months, strategies need to be devised on how to deal with such requests from test-takers, and on who carries the costs. In addition, there is a clear need for better informational and educational resources for medical professionals who may be faced with requests from their patients to help them interpret, or respond to, PGT results (in this context it is noteworthy that some PGT companies actively encourage their customers to approach doctors or genetic counsellors for further information or testing). Furthermore, the fact that 80% of those in our survey who were interested in taking a PGT test said they would want to do it to convey risk information to their children suggests that the implications that the relevance of PGT results for biological relatives – an issue which has been highlighted on GNZ – remains a serious challenge.

However the generalisability of our study may be limited due to several factors: The study group was mostly female (85%, this has to do with the composition of our volunteer cohort), and middle and higher social classes were overrepresented. All respondents live in the UK and therefore do not rely on private health insurance. Finally, all of our respondents were twins who have volunteered for genetic research, and are therefore likely to have given more thought to the topic of genetic testing than ‘average’ people.

What next?

One question that our paper cannot answer, of course, is how people who have actually taken a PGT put the information to use (if at all), and how they understand it in the first place. Much has been written about the possibility that PGT takers may not be not being able to understand the test results correctly, and as a result, suffer from increased anxiety, or groundless relief of health fears. As some of us pointed out two years ago, we are in need of solid empirical research on what those having undergone a PGT do with the results. However some of us (personal views differ among our group) also believe that the emphasis on individuals’ hypothesized inability to correctly understand their test results is rooted in an outdated understanding of genetic information as something stable and immutable, whereas PGT takes place in an era that undermines that notion of stability in many ways: Previously stable boundaries have become blurry, boundaries between medical and non-medical information, between education, information, and diagnosis, and between experts and lay people. It is certainly no longer true, in the field of genetic testing, that the expert vs non-expert divide follows the lines of professional training.

Also, it is possible that a side-effect of PGT would be that we, as a society, obtained a more realistic and nuanced image of science and scientific progress (it’s not linear, not necessarily stable, and it’s not infallible!), and of what genetic information can actually tell us – and what it can’t. However this is not meant to imply that there are no issues that need consideration with regard to the societal and regulatory aspects of PGT; many of these issues will become more, not less, pertinent if sequencing ever goes cheap and DTC. These issues include aspects of data protection and confidentiality, disclosure and applicability to family members, and ways of incorporating PGT into clinical care. For those of us who live in countries with publicly financed health care, the latter aspect raises the question of who should carry the costs for clinical consultations which take place in the context of PGT as well. For all these reasons, the activities of the members of GNZ, and the discussions on this blog, are of invaluable importance.

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3 Responses to “Guest post: Barbara Prainsack on public attitudes to DTC genetic testing”

  • Our colleague, Paul G Thorne, finds this post understandably hilarious ;-) (Think initials)

  • Daniel MacArthur

    Fantastic to see some real data being produced in this area – there’s been far too much commentary based on idle speculation over the last couple of years.

    I fully agree with Barbara that one welcome side-effect of DTC genetic testing will (hopefully) be an increase in public understanding both of genomics and science in general – although of course this will be contingent on most DTC customers receiving accurate information from testing companies (which I’d argue is currently largely the case).

    As Barbara notes, it will be particularly interesting to see the next phase of studies on people who have actually taken these tests (we’ll actually be reporting on some of these from the ASHG meeting next week).

    Hi Ed,


  • Great article. As a company employing genetic tests as part of our health profiling, we feel strong about the current DTC approach that does not involve the physician. navigenics has probably positioned themselves well to include doctors as they have a backend to their site that allows an interactive portal.

    we are employing the concept of Pathology supported genetic testing – utilizing clinical, history and pathological data to determine current status while genetic profiles allow for targeted intervention. taking the test is one thing, implementing change another. Heloise

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