Genetic testing: a conceptual exploration.

Introduction

The Advisory Committee on Genetic Testing (ACGT), in its Report on Genetic Testing for Late Onset Disorder[1] under the chairmanship of Professor Peter Harper, and the US Task Force on Genetic Testing, in Promoting Safe and Effective Genetic Testing in the United States,[2] have each attempted to define genetic testing. The Advisory Committee defines it as "testing to detect the presence or absence of, or alteration in, a particular gene, chromosome or gene product"; the US Task Force as "the analysis of human DNA, RNA, chromosomes, proteins, and certain metabolites in order to detect heritable disease related genotypes, mutations, phenotypes or karyotypes for clinical purposes". The latter explicitly states that the definition "excludes tests conducted purely for research, tests for somatic mutations as opposed to heritable mutations and testing for forensic purposes".

The ACGT carefully distinguishes between diagnostic genetic testing and predictive genetic testing, categorising the latter into presymptomatic testing and susceptibility testing, but the main body of the text is confined to "presymptomatic testing of healthy relatives with a family history of serious late onset disorder with a clear genetic basis and commonly following dominant inheritance". Issues connected with population screening, the use of genetic tests in symptomatic individuals and susceptibility testing for disorders involving multiple genetic and environmental factors are dealt with cursorily in three short appendices.

A recent paper by Peter Harper entitled, What do we mean by genetic testing?,[3] defines genetic testing as "the analysis of a specific gene, its product or function, or other DNA and chromosome analysis, to detect or exclude an alteration likely to be associated with a genetic disorder". This definition includes not only DNA tests but tests of its products and function. In the paper Professor Harper also argues that the concept of a genetic test should include not only the laboratory analysis itself, but the preliminary preparation and counselling of the patient and subsequent interpretation and support. In so far as it is possible to categorise tests as being genetic, as distinct from non-genetic, I believe his definition to be correct, including not only biochemical tests, such as those for phenylketonuria and hypercholesterolaemia, but others, such as the use of renal ultrasound in polycystic kidney disease or computerised tomography in tuberous sclerosis. For the sake of simplicity I shall, in the remainder of this paper, use the term genetic testing to refer to any type of test that indicates that a person is likely to have a genetic or familial disorder, and the term gene testing to refer to tests confined to the analysis of DNA, RNA or chromosomes.

The purpose of the reports from both the US Task Force and the Advisory Committee on Genetic Testing in the UK is to protect the public from indiscriminate genetic testing without proper safeguards and controls, and to ensure that genetic information obtained as a result of such tests is used in an appropriate manner, with adequate protection of its privacy and confidentiality. This purpose appears to be quite proper and rests on the view that genetic information is somewhat special and different from other types of health information, and requires a different and special approach from both health professionals and society. One of the most important reasons behind moves to protect the public from indiscriminate genetic testing is a fear of genetic discrimination, and of the negative actions employers, insurers, mortgage and other lenders might take against people known to have a genetic disease or susceptibility to a multifactorial disorder.[4 5] I shall attempt in this paper to look at four issues: first, to explore the meaning of genetic information and to ask if it can be adequately set apart from other types of health information; second, to explore in a similar fashion, the concept of genetic testing as a separate, identifiable category of medical test; third, to argue that the notion of regulating genetic testing as the means of addressing the problems of potential genetic discrimination and of protecting the patient and the public is misconceived, and that the morally relevant features that require certain aspects of medical practice to be regulated are not those which relate to the categorisation of a test as being genetic (as …