Predictive genetic test decisions for Huntington's disease: elucidating the test/no-test dichotomy

Predictive testing for Huntington disease over 24 years: Evolution of the profile of the participants and analysis of symptoms

BACKGROUND

Huntington disease (HD) is a devastating neurodegenerative autosomal dominant genetic condition. Predictive testing (PT) is available through a defined protocol for at-risk individuals. We analyzed the over-24-years evolution of practices regarding PT for HD in a single center.

METHODS

We gathered data from the files of all individuals seeking PT for HD in Lyon, France, from 1994 to 2017.

RESULTS

448 out of 567 participants had exploitable data. Age at consultation dichotomized over 24 years toward an eightfold increase in individuals aged >55 (2/94 vs. 30/183; 2% to 16%; p < .0001) and twice as many individuals aged 18-20 (3/94 vs. 12/183; 3%-7%; p < .05). Motives for testing remained stable. The rate of withdrawal doubled over 24 years (9/94 vs. 38/183; 9%-21%; p < .02). Independently of the time period, less withdrawal was observed for married, accompanied, at 50% risk, and symptomatic individuals, and in those able to explicit the motives for testing or taking the test to inform their children. We also assessed the consistency between the presence of subtle symptoms compatible with HD found before the test by the team's neurologist, and the positivity of the molecular test. The concordance was 100% (17/17) for associated motor and cognitive signs, 87% (27/31) for isolated motor signs, and 70% (7/10) for isolated cognitive signs. Furthermore, 91% (20/22) of individuals who requested testing because they thought they had symptoms, were indeed found carriers.

CONCLUSION

This over-24 years study underlines an increasing withdrawal from protocol and a dichotomization of participants' age. We also show a strong concordance between symptoms perceived by the neurologist or by the patient, and the subsequent positivity of the predictive molecular test.

Perceptions of the impact of chorea on health-related quality of life in Huntington disease (HD): A qualitative analysis of individuals across the HD spectrum, family members, and clinicians

Chorea, a hallmark symptom of Huntington's disease (HD), is characterized by jerky involuntary movements affecting the whole body that can interfere with daily functioning and impact health-related quality of life (HRQOL). To characterize chorea's impact on everyday functioning and HRQOL and identify patterns of perception and experiences of chorea among patients, caregivers, and providers. Data from focus groups of individuals with manifest HD (n = 8 early-stage HD; n = 16 late-stage HD), individuals at-risk or prodromal HD (n = 16), family HD caregivers (n = 17), and HD clinicians (n = 25). Focus group recordings were transcribed verbatim and analysed via constant comparison to identify meaningful and salient themes of living with chorea. Global themes of chorea's impact identified included: watching for chorea, experiences of stigma, and constraints on independence and relationships. Themes distinct to specific respondent groups included: Vigilance (at risk, prodromal); adaptation to chorea (early-stage); loss of autonomy and social life (late-stage); monitoring engagement (family caregivers) and safety (clinical providers). Living with chorea significantly constrains daily functioning, interactions, and HRQOL across the HD disease spectrum. Addressing these impacts via appropriate management of chorea can potentially enhance functioning, HRQOL, and overall satisfaction for persons with HD and their families.

Analysis of the Reasons for Non-Uptake of Predictive Testing for Huntington's Disease in Spain: A Qualitative Study

Children of persons affected by Huntington's disease (HD) have a 50% chance of inheriting the disease. Genetic testing in Spain is offered to individuals (presymptomatic test) or mothers of fetuses (prenatal) who run the risk of suffering from HD. The objective of this study is to analyze the factors that influence the decisions of adult children of persons affected with HD regarding predictive testing. A qualitative research methodology was used involving 4 focus groups (FGs) made up of adult children of persons with HD in different cities in Spain. The results of the study showed that over half of the focus group participants were inclined to decline genetic testing. The main explanatory determinants for taking or not taking the predictive test are: Maturity of the individual at risk, which was directly related to age; Ability to cope with a positive test result; Experience of living with HD sufferers; Information about testing and psychological support; Attitude of the family; Social visibility of genetic testing; Personality and temperament of each subject at risk of HD. These results imply that these factors should be analyzed in more detail in quantitative studies in order to help the Spanish Department of Health understand why some children of parents with HD decline genetic testing, so that they may and apply these data when creating specific policy regarding this issue.

"Awakening to" a new meaning of being at-risk for arrhythmogenic right ventricular cardiomyopathy: a grounded theory study

Efforts of social scientists to understand how individuals living in a family at risk for a genetically linked condition make health care decisions, having brought to the forefront the contextual nature of risk perception. Using a grounded theory approach, this study examines the experiences of 29 individuals living in families at risk for arrhythmogenic right ventricular cardiomyopathy (ARVC). Attention is paid to how individuals (re)construct the meaning of being at risk in relation to the developing science of gene discovery. Findings highlight that individuals living in a family at risk for ARVC juxtapose existing scientific knowledge against experiential knowledge as they "awaken to" the fact that they or a family member are at risk. This process is pragmatic and fluid and contingent upon whether and how symptoms are aligned with the constructed image of the at-risk relative.

"Am I carrier?" The patient's lived experience of thrombophilia genetic screening and its outcome

How do patients with thrombophilia experience a physician's request to undergo a genetic test? How do they experience the test outcome? To answer these questions, we conducted an interpretative phenomenological analysis study, based on 10 in-depth interviews with patients who underwent genetic testing for thrombophilia in Italy, half with positive and half with negative results. The experience of undergoing genetic screening for thrombophilia plays an important role in reconfiguring patients' signification of their illness experience. A positive outcome becomes a cue to reorganize in a more adaptive way the illness meaning at the cognitive and emotive levels, whereas a negative outcome appears more distressing and confusing. As a clinical implication of the study, clinicians should consider communicating carefully with the patients regardless from the positive/negative test results and they should explore the patient's specific reaction and understanding of test result.

The role of distress in uptake and response to predisposition genetic testing: the BMPR2 experience

This study examines psychological determinants and effects of participating in genetic testing among persons diagnosed with or at risk for developing primary pulmonary arterial hypertension. Longitudinal data were drawn from orally administered surveys with 70 affected or at-risk individuals concerning their thoughts, feelings, and decision making about testing for mutations in BMPR2. Distress was measured by use of the Impact of Events Scale. Variations in tolerance for ambiguity were also examined. Although uptake of testing was low, as is common for incompletely penetrant mutations that lack clear therapeutic interventions, we found that those who participated in testing evidenced greater reduction in distress compared to those who had not participated in testing, irrespective of test result. No differences in tolerance for ambiguity by testing status were found. Participation in genetic testing, irrespective of test results, may be particularly beneficial to individuals who may have genetic mutations and who are experiencing high levels of distress.

Impact of presymptomatic genetic testing for familial amyotrophic lateral sclerosis

PURPOSE

The Pre-familial Amyotrophic Lateral Sclerosis (Pre-fALS) study is a longitudinal study of individuals potentially at risk for developing familial amyotrophic lateral sclerosis. Our goals were to (1) explore participants' decisions of whether to learn results of presymptomatic testing or not; (2) understand the psychosocial impact of these decisions; and (3) assess preferences for receiving results by telephone or in person.

METHODS

The sample for this substudy comprised 20 participants drawn randomly from autosomal dominant mutant superoxide dismutase 1 families in the Pre-fALS study. Twenty participants completed a semistructured phone interview; prominent themes were identified and rated.

RESULTS

Fourteen participants chose to learn results; six had mutant superoxide dismutase 1 and eight had wild-type superoxide dismutase 1. Of the six who initially elected nondisclosure, three were reconsidering their decision. Regardless of the results and method of counseling, participants had adapted well, at least in the short term.

CONCLUSION

We recommend that (1) those considering presymptomatic genetic testing should undergo professional counseling to help decide whether to learn results; (2) discussion should include the option of telephone genetic counseling for those without easy access to in-person counseling; and (3) those who initially decline to learn results should be offered the opportunity to learn their mutation status as their decision evolves.

Epidemiology of Huntington's disease in Slovenia

OBJECTIVES

The objective of this study was to estimate the prevalence of Huntington's disease (HD) in Slovenia using direct mutation analysis.

MATERIALS AND METHODS

Symptomatic patients and presymptomatic individuals at risk for HD referred to the Institute of Medical Genetics between 1997 and 2007 were included in the study. The patients were ascertained through multiple sources. The prevalence was estimated on 31 December 2006.

RESULTS

A total of 116 and 68 individuals with CAG repeat number >36 were symptomatic and presymptomatic, respectively. The prevalence of HD in Slovenia was estimated at 5.16/10(5) (95% confidence interval 4.16-6.16).

CONCLUSIONS

This is the first report on the epidemiology and prevalence of HD in Slovenia. The prevalence of HD is comparable with previously reported data in other European countries. In Slovenia, a higher proportion of individuals at risk for HD decide on predictive mutational testing as compared with the estimated numbers for Europe, United States, Canada and Australia.

Attitudes towards and beliefs about genetic testing in the haemophilia community: a qualitative study

Widespread genetic testing for haemophilia has recently been introduced in Victoria, Australia. While attitudes towards predictive testing have been studied in other conditions, such as cancer, there is limited knowledge about the attitudes of members of the haemophilia community towards predictive testing. This study aimed at exploring attitudes towards, and beliefs about, genetic testing amongst members of the haemophilia community in Victoria prior to the widespread introduction of testing. The study was qualitative and descriptive. In-depth face to face interviews were held with a sample of 39 individuals, including men with haemophilia, female carriers and family members. Data were analysed thematically using cross-case analysis techniques. There was considerable knowledge about the proposed introduction of widespread genetic testing. However, not everyone thought that testing was accessible or user friendly, and there was confusion about who needed to be tested. Most thought that testing was necessary for adolescent girls to determine carrier status to help prepare families for a child with haemophilia, rather than leading them to choose to terminate a pregnancy or not to have children. A minority of women stated that if there was a history of inhibitors in a family then a termination might be considered. The study revealed strong religious beliefs among those studied, which may have influenced attitudes and approaches towards testing. Further investigation is needed into how people with a possible haemophilia genotype negotiate decisions about their further identification, and how this knowledge is placed within cultural, religious and family contexts.

Decision-making about reproductive choices among individuals at-risk for Huntington's disease

We explored how individuals at-risk for HD who have or have not been tested make reproductive decisions and what factors are involved. We interviewed 21 individuals (8 with and 4 without the mutation, and 9 un-tested) in-depth for 2 hours each. At-risk individuals faced a difficult series of dilemmas of whether to: get pregnant and deliver, have fetal testing, have pre-implantation genetic diagnosis, adopt, or have no children. These individuals weighed competing desires and concerns: their own desires vs. those of spouses vs. broader moral concerns (e.g., to end the disease; and/or follow dictates against abortion) vs. perceptions of the interests of current or future offspring. Quandaries arose of how much and to whom to feel responsible. Some changed their perspectives over time (e.g., first "gambling," then being more cautious). These data have critical implications for genetic counselors and other health care workers and future research, particularly as more genetic tests become available.

Engagement with genetic discrimination: concerns and experiences in the context of Huntington disease

It has been over 20 years since the inception of predictive testing for Huntington disease (HD), yet the social implications of knowing one's genetic risk for HD have not been fully explored. Genetic discrimination (GD) is a potential risk associated with predictive testing. Although anecdotal reports of GD have been documented, there is a paucity of research on the nature and experiences of GD in the context of HD. The purpose of this study was to describe the concerns and experiences of GD in the HD community. Semistructured interviews were conducted with 45 genetically tested and 10 untested individuals and analyzed using grounded theory methods. Our findings demonstrate that a majority of individuals were concerned about (37/55) and experienced GD (32/55) across a variety of contexts that extend beyond the traditionally examined contexts of insurance and employment to include family, social, government, and health-care domains. We describe a process of engagement with GD in which individuals formed meaningful interpretations of GD and personalized its risk and consequences in their lives. Our findings provide an insight into some of the specific processes and factors influencing engagement with GD. These results help identify areas where more education and support is needed and provide direction to genetic professionals supporting their clients as they confront issues of GD and genetic testing.

Living at risk: concealing risk and preserving hope in Huntington disease

Much of the qualitative research on Huntington disease has focused on the genetic testing aspects of HD. The overall purpose of this qualitative study was to gather information about the everyday experience of living with the risk of developing Huntington disease in a sample of individuals at risk for HD who have chosen not to pursue genetic testing. Data for this article was obtained from unstructured, open-ended qualitative interviews of a sample of people participating in the PHAROS study. PHAROS, the Prospective Huntington At-Risk Observational Study, is a multi-site study that aims to establish whether experienced clinicians can reliably determine the earliest clinical symptoms of Huntington disease in individuals at 50% risk for HD who have chosen not to undergo genetic testing. Interviews were conducted at six PHAROS research sites across the United States. In this paper, the research team used qualitative description to construct and explore two main themes: (1) careful concealment of risk as an act of self-preservation and (2) preserving hope.

The roles of family members, health care workers, and others in decision-making processes about genetic testing among individuals at risk for Huntington disease

PURPOSE

To understand how individuals at risk for Huntington disease view the roles of others, e.g., family members and health care workers, in decision making about genetic testing.

METHODS

Twenty-one individuals (eight mutation-positive, four mutation-negative, and nine not tested) were interviewed for approximately 2 hours each.

RESULTS

Interviewees illuminated several key aspects of the roles of family members and health care workers (in genetics and other fields) in decision making about testing that have been underexplored. Family members often felt strongly about whether an individual should get tested. Health care workers provided information and assistance with decision making and mental health referrals that were often helpful. Yet health care workers varied in knowledge and sensitivity regarding testing issues, and the quality of counseling and testing experiences can range widely. At times, health care workers without specialized knowledge of Huntington disease offered opinions of whether to test. Input from families and health care workers could also conflict with each other and with an individual's own preferences. Larger institutional and geographic contexts shaped decisions as well.

CONCLUSION

Decision-making theories applied to Huntington disease testing have frequently drawn on psychological models, yet the current data highlight the importance of social contexts and relationships in testing decisions. This report, the first to our knowledge to explore individuals' perceptions of social factors (particularly family and health care worker involvement) in Huntington disease testing decisions, has critical implications for practice, education, research, and policy.

Managing genetic discrimination: strategies used by individuals found to have the Huntington disease mutation

The introduction of predictive testing for Huntington disease (HD) over 20 years ago has led to the advent of a new group of individuals found to have the HD mutation that are currently asymptomatic, yet destined in all likelihood to become affected at some point in the future. Genetic discrimination, a social risk associated with predictive testing, is the differential treatment of individuals based on genotypic difference rather than physical characteristics. While evidence for genetic discrimination exists, little is known about how individuals found to have the HD mutation cope with the potential for or experiences of genetic discrimination. The purpose of this study was to explore how individuals found to have the HD mutation manage the risk and experience of genetic discrimination. Semi-structured individual interviews were conducted with 37 individuals who were found to have the HD mutation and analysed using grounded theory methods. The findings suggest four main strategies: "keeping low", minimizing, pre-empting and confronting genetic discrimination. Strategies varied depending on individuals' level of engagement with genetic discrimination and the nature of the experience (actual experience of genetic discrimination or concern for its potential). This exploratory framework may explain the variation in approaches and reactions to genetic discrimination among individuals living with an increased risk for HD and may offer insight for persons at risk for other late-onset genetic diseases to cope with genetic discrimination.

Discovering the family history of Huntington disease (HD)

A considerable body of research has explored both predictive genetic test decisions for Huntington disease (HD) and the impact of receiving a test result. Extant research reveals little, however, about how and when at risk persons first discover their family history of HD. Drawing upon 24 semi-structured interviews with at risk persons and their family members, this study explored initial discovery of HD in the family. Qualitative data analysis revealed four different, though sometimes related, trajectories of discovery: (1) something is wrong, (2) out of the blue, (3) knowing, but dismissing, and 4) growing up with HD. These pathways highlighted the importance of the temporal and historical contexts in which genetic risk for HD was discovered. Notably, ignorance about HD was the most salient feature shaping participants' narratives of discovery. Implications for research and clinical practice are discussed.

Gender Differences in Attitudes Among Those at Risk for Huntington's Disease

This report presents and discusses selected findings regarding gender differences from an Australian-based study that investigated attitudes of individuals at risk for Huntington's disease (HD) towards genetic risk and predictive testing. Clear gender differences emerged regarding perceived coping capacity with regard to predictive testing, as well as disclosure of the genetic risk for HD to others. Female participants were more likely to disclose their genetic risk to others, including their medical practitioners, while male participants were three times more fearful of disclosing their genetic risk to others. These findings are of interest in light of gender differences that have consistently been reported regarding the uptake of predictive testing for HD, other genetic conditions, and health services more generally. While gender differences cannot provide a fully explanatory framework for differential uptake of predictive genetic testing, men and women may experience and respond differently to the genetic risk for HD and possibly other inherited disorders. The meanings of genetic risk to men and women warrants further exploration, given anticipated increases in genetic testing for more common conditions, especially if post-test interventions are possible. These issues are also relevant within the context of individuals' concerns about the potential for discrimination on the basis of genetic risk or genetic test information.