From lab to lifestyle: translating genomics into healthcare practices

Abstract

Contemporary genomic sciences are uncovering genetic factors implicated in common complex diseases such as type 2 diabetes. It is suggested that such knowledge could be developed into tests for susceptibility to the disease that would allow preventive action through lifestyle modification. This paper presents research on responses to this suggestion by genetic specialists, diabetologists, and general practitioners – three groups of health professionals whose practices are likely to be affected by such testing services. It shows how the responses of the different groups are related to the professional culture of practice. I suggest that the perspective a profession has of its potential role in relation to the emerging technology can illuminate the early stages of co-constitution by which the technology that is used and the community of practice that use it are mutually reshaped.

Keywords:

• genetic susceptibility testing
• type 2 diabetes mellitus
• translation

Introduction

The way that contemporary genomic science might be translated into healthcare practices in the form of a “genomic medicine” has started to become a topic of debate. “Genomic medicine” is considered to be distinct from earlier “genetic medicine” (Guttmacher and Collins 2002, Khoury 2003), drawing on genomic rather than genetic science. Genetic research has been focused on identifying the DNA mutations causing single gene disorders such as Huntington's disease. Genomic science, in contrast, elucidates genetic components implicated in common diseases including diabetes, coronary heart disease and cancers through the use of technologies such as Genome Wide Association Studies (e.g. Wellcome Trust Case Control Consortium 2007). In these complex conditions, it is the interaction between genetic and environmental variables that leads to ill health. In this situation, scientists suggest, a test indicating genetic susceptibility can provide the information individuals need to guide their lifestyle choices in order to reduce their risk of developing disease (see for example Peltonen and McKusick 2001, Guttmacher and Collins 2003), a suggestion that is becoming accepted in policy circles (House of Lords: Science and Technology Committee 2009).

It has been proposed that this genomic medicine will involve healthcare practitioners dealing with “the concept of genetic information in all disease” (Khoury 2003, p. 266). Professionals themselves are considering how this concept might be accommodated within their practice. Studies have, for example, examined the attitudes of different professional groups to the use of genetic information within their work, and the educational needs of health professionals if they are to be prepared to deal with genomic medicine as part of their practice (e.g. van Langen et al. 2003, Harris et al. 2006, Farndon and Bennett 2008, McCarthy et al. 2008, McInerney 2008, Whelan et al. 2008, Carroll et al. 2009). In these studies, there is a tendency to conceptualize genomics as a novel technology that will challenge the existing skill base of practitioners, requiring their training in new techniques. The focus on the novel implications of genomic technologies for healthcare practice can be understood as a spill-over of the scientific rhetoric that emphasizes the transformative potential of the new genomic science (Brown et al. 2000, Hedgecoe and Martin 2003). However, while transformative rhetorics are important in bringing a new science into being, as that science is translated from laboratory research into tools for application in healthcare it is likely to be configured as techniques that can be “incorporated into existing clinical practices rather than sweeping them aside in a revolution” (Hedgecoe and Martin 2008, p. 826). Sociological studies of the uptake of genetic diagnostics in medical practice have shown how these new technologies “are articulated and aligned in complex ways with the pre-existing ones” as they make their way into the clinic (Keating and Cambrosio 2004, p. 19; see also Keating and Cambrosio 2003, Shaw et al. 2003, Rabeharisoa and Bourret 2009). Research into the relationship between healthcare practitioners and genomic technologies has begun to explore how professional cultures of practice might be more or less receptive to genomic medicine, according to how the technology aligns with “what we do” as a profession (Robins and Metcalfe 2004, Miller et al. 2008). This work adds to such studies by reporting how three different professions – tertiary care genetics specialists, diabetes specialists working in secondary care, and general (primary care) practitioners – consider the possibility of using genetic testing to identify and manage susceptibility to type 2 diabetes mellitus (T2DM) within their clinical practice.

Methods

I draw on two sources of data: interviews with UK-based health professionals and documentary material on the role of the three health professions studied. The main sources of documentary material were the membership organizations of UK health professions: the British Society of Human Genetics (BSHG) and its member groups, the Clinical Genetics Society and the Association of Genetic Nurses and Counsellors; the Royal College of General Practitioners; and the Royal College of Physicians (whose members include diabetes specialists) and the Association of British Clinical Diabetologists. Further material came from the UK Department of Health and the National Health Service, and from key journals such as the BMJ and the Lancet.

Alongside the collection of documentary material, semi-structured interviews were carried out with workers from professions that already deal with genetic conditions or with diabetes and which may have a role to play in testing for genetic susceptibility to T2DM: genetics specialists (n = 7), diabetologists (n = 5), and general practitioners (primary care doctors) (n = 4). Genetics specialists included both clinical geneticists (medically qualified doctors) and genetic counselors. Although the precise division of work varies in different locations, both clinical geneticists and genetic counselors may consider referrals, assess risk and counsel clients. Because of the significant overlap of work, clinical geneticists and genetic counselors were considered as one professional group. Participants came from two Primary Care Trusts (a Trust being an administrative group of primary care practices) and two hospitals in one geographical region of the NHS, one of the hospitals being home to the Regional Genetics Centre. Ethical approval was obtained from the NHS Local Research Ethics Committee. Interviews lasting between 45 and 90 minutes were carried out either by phone or in the interviewee's place of work, according to their preference. Topics covered three broad areas: current practice, future developments that participants thought might be useful to practice, and perspectives on the use of genetic testing for susceptibility to T2DM. Interviews were transcribed with participants' consent.

The analysis took an iterative approach, going between material from documentary sources and interview transcripts. The number of practitioners interviewed was small, and I make no claim that the data provides a comprehensive account of the professional view in a way that is generalizable. The aim was rather to elicit and interpret key themes in professional discourse in relation to the roles and responsibilities laid out in documentary material from professional bodies.

It should be noted at the outset that genetic susceptibility testing for T2DM is not yet part of clinical practice within the UK. The identification of genes predisposing to T2DM is, however, the subject of considerable scientific interest (for overview see Malecki 2005, Frayling and McCarthy 2007), and the condition has become something of an exemplar for researchers promoting the use of genetic susceptibility testing and provision of targeted lifestyle (particularly dietary) advice as a tool for disease prevention (Uusitupa 2005, Kaput et al. 2007, Nino-Fong et al. 2007). This scientific enthusiasm is spurring a good deal of discussion among healthcare practitioners who deal with genetics and/or diabetes. As such, it is an ideal case for studying the way that health professionals are constructing the technology and its potential role in their working practices.

This discussion among practitioners does not accept that genetic susceptibility testing and personalized lifestyle advice will become part of mainstream healthcare. Indeed, there is fierce debate on this issue, with some influential scientists maintaining that the utility of genomic knowledge will come from the greater understanding of disease mechanisms it affords rather than from any direct application as a diagnostic tool (evidence given by Professor Bobrow: House of Lords 2008). If such testing is to become part of clinical practice, there is a widespread understanding that it must be on the basis that it has been proven to be scientifically robust: the House of Lords report on Genomic medicine noted that “a commonly expressed view [of respondents] was that new genetic tests were potentially of value but required evaluation before being brought into mainstream clinical practice” (House of Lords: Science and Technology Committee 2009, p. 107). Genetic tests are required to demonstrate both clinical validity and clinical utility before introduction into routine practice within the NHS (UK Genetic Testing Network 2009), and it is considered that susceptibility tests should be no exception to this procedure. Clinical validity means that the test has been shown to predict increased disease risk in the individual; clinical utility means that it has been proven that testing leads to an improved health outcome. In discussing genetic susceptibility testing, members of all the professions I talked to expressed the caveat that it could only become part of their practice if it had been properly evaluated and shown to be scientifically robust; as one GP put it “I would just want to see the science behind that in some detail, and see just how valid it is, and how respected the actual science is” (GP 1). However, this cautiousness did not prevent them seeing past the current limitations of the technology to reflect on how, if it was proven useful in healthcare, it might or might not be useful to them in their practice.

Genetics specialists: bounded by the family

Talking to genetics specialists, I found little enthusiasm for an expansion of their remit to cover the identification of susceptibility to common complex diseases such as T2DM, even were the science behind such testing to be proven. Resources were a concern; as one clinical geneticist put it:

I suspect diagnosis of genetic susceptibility won't come through the specialist genetics services, just simply because of the sheer volume of the workload that is going to be involved when we are talking about common multifactorial diseases. (Genetics specialist 7)

However, the argument that susceptibility testing could not be provided with current resources was commonly elided with a view that such a service should not be provided by genetics specialists. So, for example, one genetic counselor considered that dealing with situations where

they've got a two-fold population risk of getting heart disease but it is not a single gene situation, or there are not lots of people in their family, it is just that they have got a slightly increased risk polymorphism, I think that would overwhelm the genetic services. I don't think we could do that. […] We have big waiting lists. For important things. (Genetics specialist 5)

This specialist went on to clarify what she considered “important things”:

If it is a Mendelian thing […] then we would see them. But if it is something like a polymorphism that is “associated” we wouldn't. We don't see families unless it looks very strongly genetic.

For another genetic counselor:

I think you would have a cut off point. So if you have got a certain percentage then there is no point us seeing you because we would just be absolutely swamped, work wise. If they are actually at quite an increased risk, […] over above 50% of the general population risk, yes, I think it is worth us seeing them. (Genetics specialist 3)

The idea being expressed here is that the work of the genetics specialist is to do with conditions where there is a strong link between a gene and development of a disease.

It is such hereditary conditions that have been a central focus of the clinical genetics service. Diseases such as Huntington's or cystic fibrosis are monogenic (caused by one gene), and have high penetrance (a high likelihood that anyone with the gene will go on to develop the disease, unmodulated by environmental variables). These conditions thus show a defined, Mendelian, pattern of inheritance. In contrast, complex diseases such as T2DM are multifactorial (many different factors, both multiple genetic elements and environmental factors, are involved in disease development), and as such the risk conferred by one particular genetic marker is low: the polymorphism is “associated” with disease but does not “cause” it. The scientific work establishing associations between genetic variables and complex conditions looks for genotype differences between healthy and unhealthy populations. Mendelian genetic science, in contrast, studies inheritance patterns within small groups – families – looking at how characteristics are stably transmitted between generations (Kevles 1995, p. 42).

Medical genetics as a specialty is founded on this notion of the “family gene,” the gene that is inherited through families and across generations. The centrality of “the family” for their work is made clear in the logo of the British Society for Human Genetics, the professional body for UK genetics specialists:

(www.bshg.org.uk)

It is explained:

The squares and circles in the logo are taken from the standard symbols for male and female in a family tree diagram. The series of individuals one after another represents the generations in a family who may be affected by a genetic condition. (British Society for Human Genetics 2005)

This explanation points first to the importance of the family tree diagram in the work of genetics specialists. Although DNA-based diagnostics are becoming increasingly available, within clinical genetics services such genetic testing is far from routine. In practice, diagnosis relies centrally on family history information (Gibbon 2002, Nukaga 2002). It is the family history of disease that determines which referrals coming into clinical genetics centers are deemed worth further investigation, and in the genetics clinic it is the family history chart that is the primary tool used to identify whether a particular member of that family is at genetic risk, as illustrated in the NHS guidelines for management of familial breast cancer (National Institute for Health and Clinical Excellence 2006, pp. 27–28). As these guidelines make explicit, “genetic testing is only appropriate for a small number of women from high-risk families” (National Institute for Health and Clinical Excellence 2006, p. 31). More generally, the Care Pathway for clinical genetics in the NHS makes the assessment of pedigree central to the clinical encounter (Temple and Westwood 2006, p. 31).

Further, as the explanation of the BSHG logo also indicates, the profession is concerned with the wider family that may be affected by a genetic condition, not just the one individual seen in a specific clinical encounter. The focus on the family as part of working practice is made explicit in the guidelines for clinical genetics in the NHS. Lead-authored by a clinical geneticist and a genetic counselor (with input from the wider professional community), this document states:

In clinical genetics, the fundamental unit of responsibility is the “family” and includes not only the “sick” individual who presents for diagnosis and treatment but also the family members who are identified as being at-risk. (Temple and Westwood 2006, p. 6)

This idea that the specialist genetics service deals with families rather than individual patients was reflected in my interviews with individual practitioners:

Within genetics we are very aware of the family issues of genetic testing and we often feel that, you know, it can be described as being unethical to do genetic tests without consideration of the impact on other members of the family. (Genetics specialist 1)

When we see patients, we would obviously discuss with them their risk, but we would also discuss their siblings' risk, children's risk, parents' risk. (Genetics specialist 3)

It is not about a single patient, it is about a family and the relationships in a family can be affected by it. (Genetics specialist 7)

Indeed, the ability to see the wider family picture was considered a key skill that defines the specialist expertise of the clinical geneticist or genetic counselor:

techniques that we have specialized in, in terms of consent and confidentiality and thinking of the extended family and not just the patient in front of you, all that kind of stuff that is actually a bit alien to a lot of departments of medicine, they just think of the patient and not their sister. (Genetics specialist 6)

Dealing with risk as it affects the whole family is not just “what we (as genetics specialists) do” but is something that other medical specialties do not do.

Several elements of the work of the genetics specialist are enrolled into this concern with “the family.” Medical genetics has dealt in diseases that are severe and life shortening, and which have impacts on the family along a number of lines. Identification of a risky gene within the family is not infrequently used to guide decisions on the production of new family members. Clinical genetics as a specialty is directed at providing information and support to those at genetic risk as they make such decisions (Clinical Genetics Society undated): whether to undergo pre-natal screening and possible selective abortion of an affected fetus; whether to employ pre-implantation genetic diagnosis and IVF to ensure only pregnancies free from such risky genes are initiated; potentially, whether to conceive a child from one's own gametes at all. Further, the nature of the conditions dealt with by the specialist genetics service means that identification of the disease within the family has a special impact on others who may become at risk themselves or whose loved ones may be at risk. While a greater understanding of the molecular basis of disease is starting to lead to new treatment options that can prolong life, for many of these genetic conditions medical science can still offer no cure, and where curative treatments are available (as in the familial cancers that are an increasing part of the work of the specialist genetics service) they are by no means easy and have no guarantee of effectiveness. The only “preventive” action that is so far possible in relation to such conditions is early detection through screening (so increasing the likelihood that treatment will be successful) or prophylactic surgery. Diagnosis of such conditions – where there is a high degree of inevitability that they will develop, and where treatment or preventive options are limited – has implications for the whole family.

Genetic testing for susceptibility to complex diseases such as T2DM does not raise the same issues to do with the family. While complex diseases may cluster in families, the disease trait does not segregate along Mendelian lines, and so cannot be tracked through the pedigree charts and located in specific individuals as with “genetic diseases.” Because a genetic marker is only associated with the disease, rather than conferring certainty, or at least significantly increased risk, of illness, the reverberations within the family of a diagnosis of susceptibility are not the same as for a diagnosis of genetic disease. Perhaps as importantly, because it is a combination of genetic and environmental factors that are involved in the transition from susceptibility to sickness, there are preventative actions that can be taken – watching one's diet, taking exercise, and avoiding obesity, for example, to reduce risk of T2DM. As such, diagnosis of susceptibility in one individual does not have the same implications for other family members, including that individual's own future offspring, as diagnosis of an implacable genetic disease. Mendelian genetics, and the genetic medicine upon which it is founded, situate the gene in the context of the family, as an entity that links family members together in risk, whereas contemporary genomics, and the genomic medicine that is evolving from it, situate the gene in the context of the cell, within an individual body, as one factor of risk among many others in the cellular environment.

As genetics is spreading from being a specialist area of medicine to being part of the knowledge base of all areas of healthcare, genetics professionals are caught in something of a double bind. Recognition that genetic information is important in the management of health and disease reinforces the status of genetics as a specialty, but simultaneously suggests that, if genetics is of such universal value, it should be part of the core expertise of all health professionals. Genetics specialists must establish a remit for their practice that defines it as distinct from the use of genetics more widely in medicine – what counts as genetic (and so part of their practice) and what is the use of genomic information as an aid in other areas of medicine (and so not properly part of their work). It is the focus on the family, rather than the individual, that is used to define genetics as a specialty. Envisaging genetic susceptibility testing as “not about families” configures it as “not what we do,” and as a corollary shapes “what we do” (as genetics specialists) as being about families.

Diabetes specialists: a “salvage service” for severe disease

While genetics specialists did not see testing for susceptibility to complex disease as falling within their remit, they did recognize a role for such testing as part of medicine. They suggested that such work would best be carried out within the relevant clinical specialty:

Yes, they probably will go through some type of genetic counseling, but I'd be very surprised if they actually came through us. […] So if you took diabetes for instance, you would get a specialist diabetes nurse who will go off and do a genetics course about diabetes and will then actually be able to support the patients through that route. (Genetics specialist 4)

There is a view here that, while genetic susceptibility testing is not within the remit of specialist genetics services, it is still a specialist activity, and should be carried out by those with specialist expertise in both genetics and the relevant disease area.

Genetics research has already had some impact on the specialty of diabetology. A number of genetic mutations resulting in decreased sensitivity to insulin and leading to a subtype of T2DM known as Maturity Onset Diabetes of the Young (MODY) have been identified (Fajans et al. 2001). MODY typically presents in the second or third decade of life, and is not associated with obesity. As such, it was frequently diagnosed as type 1 diabetes, brought about by a defect in insulin secretion and requiring lifelong therapy with injected insulin. The preferred treatment for MODY is, in the first instance, dietary modification and oral medication. However, there was no clear suggestion among diabetes specialists that genetic testing itself was useful for identifying those with MODY rather than type 1 diabetes:

We can directly measure their insulin levels in the body, so if the levels are very low we know the problem is with secretion, whereas if the level is high then we know it is type 2 diabetes. So we already have tools to do that, if we want to. We are often fairly certain what we are dealing with. From a clinical presentation. (Diabetologist 1)

Another (Diabetologist 4) commented that MODY was commonly identified from family history, and she often did not bother with genetic testing to confirm. She considered that for further such developments to be useful it would be necessary “to have the genetics actually identified clearly, and available without having very expensive tests to perform.” In other words, although the genetic research has allowed stratification of T2DM into different sub-types, genetic testing itself is not a particularly necessary or useful clinical tool, and is unlikely to replace clinical judgment in diagnosing disease. Such a prioritization of clinical judgment over new technological aids for diagnosis of genetic risk has been shown to operate within genetics clinics (Wood et al. 2003).

Not only did diabetologists prioritize clinical judgment over technological aids for diagnosis, they also suggested that

we do know that there are some families in which there is definitely a genetic component. I think unfortunately anyway the treatment is the same, it doesn't change our treatment. (Diabetologist 4)

Whereas the scientific identification of MODY as a sub-type of T2DM has made a difference to treatment, the perception here is that genetic testing for generalized predisposition to T2DM will not alter the therapeutic options for the patient, and it therefore has little utility. A similar perspective on pharmacogenetic testing has been identified among UK oncologists (Hedgecoe 2004, p. 108). In this vein, I found that when the issue was presented to diabetologists as one of using genetic testing to identify those who were highly predisposed to developing complications related to their underlying disease (rather than to stratify patients according to the sub-type of disease), their response was more positive:

AH: And would genetic testing be useful in relation to complications that might develop?

Diabetologist 1: I think that is very useful probably, because we have seen people who have very poor control but that doesn't give any complications, some people have good control and in a very short time they develop complications. I think that is a very interesting area, if you can see if there is a genetic predisposition to develop complications. That is an interesting area.

Both Diabetologist 2 and Diabetologist 3 cautioned that such testing would only be useful (rather than an interesting prospect) if it made it possible to “do something about it,” but they did foresee such a possibility, in terms of being “more aggressive in terms of metabolic control” (Diabetologist 4), either through patient education or through medication.

Diabetes specialists regarded genetic testing to identify those at risk of developing complications as being properly part of their professional role:

AH: And if genetic testing for susceptibility to complications came in is that something that you would like to see being done in a diabetic clinic, or a genetic clinic or primary care?

Diabetologist 2: It would have to be normal diabetes.

Such enthusiasm for testing that might help in dealing with diabetic complications can be related to the core work of the diabetes specialist. One specialist explained how “management of diabetes is being devolved into primary care, more and more” (Diabetologist 2), largely because of the sheer numbers of people developing the condition. Nowadays, even those type 2 diabetics who require transition to insulin are being managed in primary care. For the secondary care diabetes service:

What we are going to be is sort of the “insulin failure service” [seeing those who are on insulin therapy, but having problems]. So then they will be that much further down the complications. So we will be salvaging complications. That is what we do here at the moment. We salvage complications. (Diabetologist 2)

As a service that is centered on salvaging complications, the use of genetics to identify those most at risk of such complications is therefore a potentially useful addition to the repertoire of skills used by the diabetes specialist.

Diabetes specialists are, then, involved in preventive healthcare, but this is tertiary prevention: prevention of complications arising from extant disease. The focus of diabetology as a clinical specialty is made clear in the chapter of the Royal College of Physicians publication Consultant physicians working with patients (Royal College of Physicians 2008, p. 136) on diabetes and endocrinology:

The best current estimate is that the increased prevalence and longevity of people with diabetes and the increased complexity of care […] will mean an increase in the workload of diabetes specialists. The nature of that work is likely to change quite radically with more time devoted to problem solving and support of primary and specialist colleagues.

This view correlates with the notion of diabetology becoming a “salvage service” for complications. Primary prevention (preventing disease arising in the first place) is not part of diabetologists' work:

If you could identify the ones who are more likely to be prone to develop diabetes, um, it is not us, in terms of public health, I would say. […] What we do in terms of prevention is not primary prevention. (Diabetologist 4)

This is not to say that individual physicians (or the Royal College, as their professional body) are not interested in primary prevention. All of the diabetologists I interviewed were interested in strategies for reducing incidence of T2DM (such as tackling increasing levels of obesity in the population) and the problems of putting these into practice (such as lack of individual or political will). However, genetic testing for susceptibility to diabetes is not properly part of their clinical work, which is treating extant disease. Nevertheless, genetic testing could be incorporated as part of diabetes specialist practice if it was directed at tertiary rather than primary prevention: prevention of diabetic complications rather than prevention of diabetes itself, as the professional identity is evolving to become one of a “salvage service” focused on severe, complicated and complicating disease.

Primary care: treating individuals, managing risk

In contrast to genetics specialists and diabetologists, general practitioners (primary care doctors) regarded the use of genetic susceptibility testing in a more favorable light:

AH: And if genetic testing became available that could indicate susceptibility to chronic conditions, is that something you think you would be equipped to deal with in primary care?

GP 2: I think to a degree we would be. Because I think we would treat it very much as yet another risk factor just like family history would be a risk factor, and we would look at what we could do to reduce an individual's risk.

AH: If genetic testing became possible to look at susceptibility for developing some of these chronic conditions, do you think that would be a useful addition to some of the things you can do already?

GP 4: Yes, definitely. Because at the moment I am looking at risks anyway, just normal family history, and if someone has a strong family history I will be emphasizing it more anyway. So yes, that would be just another one. You know, it would just be another issue.

Two elements of GPs' work can be identified as underpinning the potential incorporation of diagnosis and management of genetic susceptibility to complex disease within existing practice, while excluding management of Mendelian conditions: they deal with identifying risk and preventing disease; and they are primarily concerned with individual patients (considered in the context of their families but not as families).

In the UK, disease prevention has become an increasingly important part of the work of general practice. Disease prevention, through practices such as health education and vaccination, has always been a part of primary care work. However, from 1990 changes to the contract between GPs and the State have encouraged the provision of a greater number of health promotion activities with primary care (Williams et al. 1993). As one GP explained:

In the old days when I started work it was basically […] getting ill people and making them better. But the emphasis has changed in the last two decades into trying to be more of a preventative service. A lot of the way the government has altered the administration of general practice is to try and prevent illness. (GP 1)

Thus today “a large chunk of our routine day-to-day work is prevention” (GP 2). Practically, this means that, as suggested in the interview extracts in the preceding paragraph, GPs are dealing with risks on a regular basis. GPs are already well versed in the use of various technologies for identification of risk, such as measurements of blood pressure, blood lipid levels, blood glucose concentrations (Getz et al. 2003, p. 498), and indeed family history information. They are adept at analyzing risk information relating to common multifactorial diseases such as cardiovascular disease using tools such as the Framingham Risk Assessment Tool, which (as GP 3 explained) allows her to input variables such as cholesterol level, blood pressure, smoking status and age and obtain an estimate of the 10-year risk of coronary heart disease. Once a patient has been identified as being at risk, a key part of the work of general practice is providing assistance to that patient to manage their risk, whether through pharmacological intervention (prescribing statins for those with high cholesterol for example) or support in making lifestyle changes:

I try and get it [lifestyle advice] into most consultations, if it is relevant. For example with most conditions lifestyle can make a difference and I will often use phrases like “well of course using a normal healthy diet which we should all be following anyway.” And emphasizing what they should and shouldn't be doing. (GP 4)

Dealing with the identification and management of risk of complex disease is, then, already a core part of the work of primary care physicians, and the use of genetic susceptibility testing can be accommodated as “just another sort of risk information,” alongside factors such as cholesterol level and family history information.

The patient, in primary care, is the individual: “GPs offer care that is personal, focused mainly on the individual patient” (Royal College of General Practitioners 2004, p. 4), or as one GP put it, “the way that we work is person-centered. Individual work” (GP 3). Of course, the GP, traditionally a “family doctor,” may treat several members of one family. They may consider family history in making a diagnosis, and take family circumstances into account in considering treatment options. But their concern in a specific consultation is with the individual patient. They are “personal doctors” (Royal College of General Practitioners, 2007b, p. 1). Further, the GP is an expert in caring for the whole patient, potentially managing multiple morbidities as they affect the patient throughout their life (Royal College of General Practitioners 2007a, p. 13), and taking into account any wider social issues and circumstances (Royal College of General Practitioners 2007a, p. 10). Their role is “seeing the patient as a unique person in a unique context” and “providing long term continuity of care” (Royal College of General Practitioners 2007a, pp. 10, 11) – taking a holistic approach to caring for the patient as an individual, with specific circumstances, over the full course of their life. While the genetics specialist is concerned with “one illness, many family members” the GP is concerned with “one person, many illnesses.”

Given their role in caring for the individual and their skills at dealing with risk, primary care can be considered the proper place for genetic susceptibility testing, which allows identification of a person's specific risk of disease, to take place:

If we were able to do a test in primary care and then find out a person was prone to a disease, we could then give the initial focused preventative care to that patient, before referring to secondary care if further treatment was required. […] I think quite definitely genetic testing if it can be done in primary care should be. Because we are the ones who get to know patients over many years, and they develop a trust in the GP which they may not have in a hospital consultant who is very erudite but only sees them once in a blue moon. As a GP you can get a certain sort of rapport. (GP 1)

The above extract reflects the key characteristics of the primary care practitioner that are identified in the 2003 White Paper on genetics produced by the UK Department of Health as suiting them for a leading role in dealing with the genetic susceptibility to complex disease:

They work with individuals in the context of their families over time. They are adept at identifying health problems and making appropriate referrals. They co-ordinate the care of the affected patient. And they are at the forefront of health promotion and prevention. (Department of Health 2003, pp. 39–40)

For the GP identification and management of a patient's risk of disease is already a core part of their work. As such, genetic susceptibility testing is a new tool to add to the armory of techniques already employed by the GP, rather than an activity that would require reconfiguration of existing practice.

Discussion

In this article, I report that general practitioners give a generally positive response to the potential for using genetic testing for susceptibility to conditions such as T2DM within their practice. Previous research has indicated ambivalence among GPs to genetics. It has been reported that GPs recognize that they are likely to have to deal with genetics, but are concerned that they lack the requisite knowledge and skills, the conclusion being that education of primary care providers in genetics is necessary (Emery et al. 1999, Watson et al. 1999, Greendale and Pyeritz 2001). As an alternative to this “knowledge deficit” model, it has been suggested that their response is “about how GPs relate genetics to their professional practices and identity” (Robins and Metcalfe 2004, p. 225). In this vein, earlier studies have proposed that genetic medicine is in conflict with core values of general practice in the way it is understood to overly prioritize biological explanations of disease (rather than giving consideration to the multiple factors – biological social, psychological, environmental – that impact on patients' well-being) and in the “therapeutic gap” with which it is associated wherein there is a lack of effective options that the physician can offer in the face of a genetic diagnosis (Kumar 1999, Kumar and Gantley 1999, Elwyn et al. 2002). My study suggests that GPs recognize the distinction between genetic and genomic medicine that is emerging from science, with the latter situating the gene as one element in the complex process of disease development, understanding of which is producing more effective options for preventive intervention. As such, genetic susceptibility testing is regarded by GPs as a tool that could be a useful addition to professional practice because it aligns with their role as doctors who identify health risks and help patients to manage those risks through lifestyle modifications.

Conversely, for diabetologists and genetics specialists, susceptibility testing to identify individuals at risk is not part of “what we do” (cf. Miller et al. 2008). However, the idea that genetic susceptibility testing does not fit easily within specialist genetics or diabetology practices as they are currently configured does not mean that such testing could not be accommodated. The professional culture is not static, and genetics services have evolved alongside the development of new types of genetic diagnosis. The genetics service has changed: from being a service focused on pre-natal screening, it has incorporated identification and support of those carrying genes for late onset disorders such as Huntington's disease, and more recently has expanded its role to include counseling those at risk of hereditary cancers. The role of the genetics specialist has evolved alongside the new technologies to include working to support individuals in disease prevention activities, such as having regular mammograms or colonoscopies to detect early signs of breast or bowel cancer. As such, the founding principle of genetic counseling, non-directiveness, is now being joined by the principle of prevention (Koch and Svendsen 2005, Stemerding and Nelis 2006). The reconstitution of professional communities of practice around the development of new technologies does not necessarily take the form of a turf war between existing disciplines over who should control the technology. Diagnosis and management of hereditary cancers, for example, is not a practice that is exclusive to either genetics specialists or oncologists. There are indications that a new hybrid or super-specialty is emerging around cancer genetics, as evidenced in the establishment of the “Cancer Genetics Group” as a constituent group of the British Society of Human Genetics.

Conclusions

The “genetic test” is not scientific knowledge stabilized into an artifact that can be used by medicine, and neither do medical professions have a fixed identity. The question is not one of identifying a likely “fit” between technology and profession, for both the profession and the technology are open to (re)shaping. As studies in the sociology of technology have shown, technology and society are mutually constituted (Bijker and Law 1992, Oudshoorn and Pinch 2005) such that users are shaped by the technology as they simultaneously play a part in its configuration. There has been a process of “ongoing mutual adjustments between laboratory and clinical practices” (Keating and Cambrosio 2004, p. 39) for any new technique that has entered routine clinical use.

Users of medical technologies include not just health professionals, but also those on whom the technologies are applied as diagnostic or therapeutic tools. Those who take a genetic susceptibility test and receive targeted lifestyle advice, whether as patients in a clinical context, or indeed as consumers purchasing such services directly without the mediation of a health professional, will also shape and be shaped by the technology, as I have started to investigate elsewhere (Harvey 2009, 2010). My focus in this paper has been on the health professional as user. For such users, the professional “community of practice” (Clarke 1998) and the tools used as part of practice – what “we do” and the tools we use to do it – are mutually constituted. The technology achieves meaning in the context of its use (Wailoo 1997) and simultaneously use of the technology confers meaning on professional practice.

It is not only the professional culture that is fluid. Genetic susceptibility testing is not a black-boxed product produced by the laboratory to be applied in healthcare practice. Users and potential users will be integral to the form it takes as it is translated from the laboratory to become a resource for provision of personalized risk diagnosis and lifestyle advice. As I noted earlier, all the professional groups I talked to emphasized that they would need to be assured of the scientific robustness of the technology before they would consider it suitable for use within their practice. How “robustness” is defined is likely to vary, however, between the different user groups, and the way this demand for (different forms of) “robustness” is accommodated by scientific development of the technology will be important in the translation of genomic susceptibility testing into healthcare practices.

While the co-constitution of a “robust” or “useful” genetic susceptibility test through mutual development of professional and scientific practices requires further study, there is an indication that, in their configuration of genetic susceptibility testing as part of “what we do,” GPs have a particular vision of such testing. One GP explained how she already used the Framingham Risk Assessment Tool to estimate a patient's risk of coronary heart disease, and suggested:

If you could add it in, that if you have got this gene, and this is a risk factor, that means you should eat this, why not. (GP 3)

For this GP, a genetic test was envisaged as producing a defined risk factor estimate that could be input into the Tool, in the same way as a blood pressure measurement or cholesterol level figure. In a similar vein, another GP suggested that genetic testing would help with communicating risk to patients because

patients don't like doubt. They like hard figures. […]. I would hope that we can get with genetic testing much more specific, simple to understand ways of explaining it to patients. (GP 1)

Again, the genetic test is envisaged as providing some “hard figures,” a concrete estimation of risk. Such a vision contrasts with the existing format of genetic testing, where the presence or absence of a genetic marker does not itself confer a specific degree of risk, but is a factor that is considered by the clinician alongside other relevant risk information (notably family history information) in making his/her judgment as to whether the person is “at risk.” We can, then, suggest that whether practitioners see genetic susceptibility testing as potentially part of “what we do” depends on what they see. It depends on the vision they have of the form that such testing will take, and on how they see their professional role, and whether the two align to reinforce each other.

This study has, of necessity, had little to say about the mutual shaping of the technology and the user as genetic susceptibility testing for T2DM is not currently being employed within NHS clinical practice. Further work will be needed to follow the path that genomics takes as it is translated from lab to lifestyle, to examine which, if any, of the above professions do incorporate it as part of their practice, and the process by which this happens. This process is unlikely to involve radical changes to professional practice, neither is it likely to be one of seamless integration of a well-defined technology into the repertoire of techniques already operated by a particular profession. Instead, the technology of genetic susceptibility testing and the character of the health profession are likely to be mutually (re)constituted. The perspective that a profession has of its potential role in relation to the technology can illuminate the early stages of this process of co-constitution.

Acknowledgements

This work was supported by an ESRC/MRC studentship (PTA-037-2004-00011) and an ESRC postdoctoral fellowship (PTA-026-27-1869). I would like to thank Clare Williams, Kathryn Ehrich, Barbara Prainsack, and Steven Wainwright who all provided constructive advice on earlier drafts of this paper. I would also like to thank the two anonymous NGS reviewers for their helpful comments which were greatly appreciated.