'It was the missing piece' Predictive genetic testing in young people for adult onset conditions

2017-05-22T04:15:16Z (GMT) by Mand, Cara Maree
Predictive genetic testing for adult onset genetic conditions, such as Huntington’s disease, is an accepted element of the standard of care for at risk adults. Conversely, there is continuing controversy in regard to testing young people, specifically those younger than 18 years, at risk for adult onset genetic conditions for which there are no effective medical interventions before adulthood. Guidelines recommend testing is deferred in these cases until a young person reaches the age of majority. Arguments against testing have concentrated upon potential harms flowing from testing, and have questioned the capacity of young people to provide informed consent. Recent evidence shows some clinicians are making their own determination as to the best interests and capacities of individual young people and are providing testing in some cases. These tests have largely occurred outside of a research framework; missed opportunities to move from an opinion-driven discourse and build an evidence base to guide future practice. This thesis aims to address this research gap by directly engaging with young people to explore their experiences and views to inform the current ethical discourse and contribute to a developing empirical evidence base. Following on from an overview of relevant international guidelines and literature review I show that, despite increasing opportunities for directly relevant empirical research, opinions regarding the likely consequences of predictive testing in young people rely on extrapolation from adult research combined with speculation built upon supposed special vulnerability in childhood and adolescence. Against this background, I present my own empirical research, incorporating qualitative methodology in conducting and analysing in-depth interviews with two groups of young people. First, I describe the findings from interviews with eight of a possible nine young people across two Australian states who have participated in predictive genetic testing as minors for adult onset conditions including familial cancer syndromes and neurogenetic conditions where no effective intervention is available prior to adulthood, if at all. Secondly, I describe the outcomes of ten interviews with young people at risk for Huntington’s disease, none of whom had participated in a predictive genetic test. For the first time, I present evidence that potential adverse consequences of testing raised by commentators may have been overstated and highlight a range of previously unreported harms and benefits associated with both gene- positive and negative test results. Of concern, institutional testing processes were almost universally a focus of strong dissatisfaction and participants identified these processes as an independent cause of distress. Findings from the untested group at risk for Huntington’s disease reinforce previous research findings that living at risk in a family affected by a genetic condition may be associated with harms independent of considerations of testing. For both groups, I highlight the unique individual circumstances from which a request for testing may emerge, and the danger in assuming that these young people conform to an adolescent stereotype or that a generic list of potential harms and benefits may be applied in every case. Some young people living at risk in a family affected by a genetic condition are thinking about and want to talk about predictive genetic testing. The evidence presented in this thesis suggests that a highly personalised assessment, considering past experiences and personal beliefs to measure task specific competence and predict potential harms and benefits, may find young people who are competent to provide informed consent and for whom predictive testing is in their best interests.