Abstract and Introduction
Direct-to-consumer genetic and genomic tests have been offered for over a decade. With the reduction in the cost of sequencing, the options for consumers will increase, with subsequent pressure on health services to interpret data and integrate the results into healthcare management. However, indications are that health professionals are grossly unprepared to deal with requests for support from those who have undertaken direct-to-consumer genetic or genomic tests. While benefits may be derived from patient-driven investigations, distinction needs to be made between the mostly uncertain clinical utility of susceptibility testing and the potential benefits of a reliably interpreted sequencing result. It is essential that we develop strategies, including enhanced professional education, to cope with the potential impact on the health services, rather than ignoring these developments. There may also be implications for the future of genetic counseling, with potential changes in the current paradigm.
The paradigm shift in medicine that has resulted from the increase in understanding of the relationship between, genes, health and disease is well documented in a range of clinical settings.[1–4] Increases in knowledge, as well as technological advances in testing, have enhanced the options for testing to determine an individual's likelihood of developing or passing on a genetic condition, or their susceptibility to more common diseases.[6,7] The term 'genetic tests' is generally used to define those tests relevant to rare single gene disorders (such as cystic fibrosis or Huntington's disease), where the main influence on the development of the disorder is a mutation or mutations in single genes. The science of genomics relates to conditions where there is both a genetic and environmental influence, in which genes interact with other genes and the environment, and genomic tests may be performed in relation to susceptibility for common diseases such as coronary heart disease. In this article, we will discuss the options for genetic or genomic testing available to patients and the potential motivation for patients seeking direct-to-consumer (DTC) genetic or genomic tests. In addition, we will consider the preparedness of health professionals to support patients considering such a route and possible implications for professional education on this topic. As we are referring to health professional competence, in this article we will use the term patient rather than client or consumer, although we acknowledge that in many cases the person seeking healthcare advice will be healthy.
In clinical practice, genetic tests based on the analysis of genetic material (typically chromosomes, DNA or RNA) are carried out in the context of: diagnostic testing for genetic conditions, carrier testing for autosomal or X-linked recessive conditions and presymptomatic testing for autosomal dominant conditions. In addition, prenatal diagnosis of a fetus at risk of a genetic condition is available for many disorders. It is strongly recommended that appropriate counseling accompanies all such testing to enable patients to make informed decisions about whether to accept or decline such a test. For example, the European guidelines for presymptomatic testing developed as part of the EuroGentest project emphasize the need for pre- and post-test counseling by trained health professionals to enable patients to determine whether the test is appropriate for them in the context of their own beliefs, values and lifestyle. European guidance on prenatal testing includes the same requirements. To achieve this, an individualized approach to each patient is required. However, an ethical question can be raised by this requirement; if a patient does not wish to have counseling, is this simply an expression of their individual choice and should the health professional insist? Patients may feel that they have given sufficient thought to the decision over years or even decades, while the health professional who is offering an intervention in the form of a test has a responsibility to ensure as far as possible (within the boundaries of professional practice) that the intervention causes no harm to the patient. While the need for informed consent is paramount in the health professional's perception of ethical practice, evidence suggests that the public place more emphasis on the access to appropriate information, which is of course one component (alongside voluntariness and capacity of the patient to make a decision) of informed consent. This does, however, emphasize the expectation of patients that health professionals are knowledgeable about both genetic and genomic testing offered within the health service,[14,15] and they may also expect them to understand health-related tests offered by private companies.
With the developments in genomics, it has become possible to undertake what are termed susceptibility tests to determine the likelihood of an individual developing a multifactorial condition caused by a combination of genetic and environmental influences. Susceptibility testing is usually based on genome-wide association studies and these tests are far less likely to be offered in clinical practice because of the lack of clinical utility associated with the results. For example, in a scenario provided on the '23andMe' website, a patient is told that their risk of coronary disease between the ages of 45 and 79 is 46.3%, compared with the risk within the general population of 46.8%. This is likely to offer less relevant information about management than that obtained via taking a family history, taking account of BMI, lifestyle choices, and measuring cholesterol and lipid levels. In fact, the majority of respondents to one study of DTC users said they had not altered their lifestyle or health management at all since receiving the results. While knowledge of increased genetic predisposition may motivate some patients to pursue a healthier lifestyle or screening, others may see the disease state as inevitable due to genomic factors and take less responsibility for their health.[19,20]
Personalized Medicine. 2013;10(7):673-682. © 2013 Future Medicine Ltd.