The Effect of Predictive Testing in Adult-Onset Neurodegenerative Diseases on Social and Personal Life

Genetic diagnosis of individuals at risk of CADASIL: prospect for future therapeutic development

CADASIL is the most frequent hereditary cerebral small vessel disease worldwide. The disease is responsible for a slow and progressive accumulation of cerebral ischemic insults that lead to disabling cognitive and motor symptoms at late age. Although there is currently no cure for this condition, future therapies may concern subjects only at early stage of the disease. This will raise the question of the participation of asymptomatic carriers of pathogenic NOTCH3 gene mutation in future clinical trials, which will presuppose acceptance of presymptomatic genetic diagnosis. In this study, we questioned the population at risk of CADASIL who had not undergone a diagnostic procedure yet. Based on a questionnaire survey carried out by an independent team of sociologists, we analyzed what underlies the choice of people at risk to undergo or not to undergo a genetic test, and what could constitute the tipping point that could lead people who were initially not interested in their diagnosis to have recourse to it. Our results suggest that, far from being a simple, unequivocal path, the decision-making process leading to the choice of diagnosis is initially slowed down by the need to distance oneself from the disease so that it doesn't take over one's life, and then evolves under the influence of a complex tangle between advancing age, the presence of early symptoms, and the personal relationship with uncertainty. It cannot be ruled out that the real and imminent prospect of therapy may also modify responses to this type of survey.

Demographic Characteristics Associated With Perceptions of Personal Utility in Genetic and Genomic Testing: A Systematic Review

Importance

The expansion of genetic and genomic testing in health care has led to recognition that these tests provide personal as well as clinical utility to patients and families. However, available systematic reviews on this topic have not reported the demographic backgrounds of participants in studies of personal utility, leaving generalizability unclear.

Objective

To determine the demographic characteristics of participants in studies examining the personal utility of genetic and genomic testing in health care.

Evidence Review

For this systematic review, we utilized and updated the results of a highly cited 2017 systematic review on the personal utility of genetics and genomics, which identified relevant articles published between January 1, 2003, and August 4, 2016. We also used the original methods to update this bibliography with literature published subsequently up to January 1, 2022. Studies were screened for eligibility by 2 independent reviewers. Eligible studies reported empirical data on the perspectives of patients, family members, and/or the general public in the US on the personal utility of any type of health-related genetic or genomic test. We utilized a standardized codebook to extract study and participant characteristics. We summarized demographic characteristics descriptively across all studies and by subgroup based on study and participant characteristics.

Findings

We included 52 studies with 13 251 eligible participants. Sex or gender was the most frequently reported demographic characteristic (48 studies [92.3%]), followed by race and ethnicity (40 studies [76.9%]), education (38 studies [73.1%]), and income (26 studies [50.0%]). Across studies, participants disproportionately were women or female (mean [SD], 70.8% [20.5%]), were White (mean [SD], 76.1% [22.0%]), had a college degree or higher (mean [SD], 64.5% [19.9%]), and reported income above the US median (mean [SD], 67.4% [19.2%]). Examination of subgroups of results by study and participant characteristics evidenced only small shifts in demographic characteristics.

Conclusions and Relevance

This systematic review examined the demographic characteristics of individual participants in studies of the personal utility of health-related genetic and genomic testing in the US. The results suggest that participants in these studies were disproportionately White, college-educated women with above-average income. Understanding the perspectives of more diverse individuals regarding the personal utility of genetic and genomic testing may inform barriers to research recruitment and uptake of clinical testing in currently underrepresented populations.

Psychological Impact of Predictive Genetic Testing for Inherited Alzheimer Disease and Frontotemporal Dementia: The IT-DIAfN Protocol

AIM

Our aim was to evaluate the psychological impact of predictive genetic testing in individuals at-risk for inherited dementia who underwent a structured counseling and testing protocol.

METHODS

Participants were healthy at-risk relatives from families with at least one affected patient, in whom a disease-associated genetic variant had been ascertained. A comprehensive psychological assessment (personality, anxiety and depression, quality of life, coping strategies, resilience and health-related beliefs) was administered at baseline, at 6 months and 12 months follow-up.

RESULTS

Twenty-four participants from 13 families were included. Sixteen participants underwent blood sampling and genetic analysis; 6 resulted to be carriers of pathogenic variants (1 in PSEN1, 1 in PSEN2, 4 in GRN). Carriers showed higher score on the Resilience Scale for Adults (RSA) - social competence, and on Multidimensional Health Locus of Control - internal, than noncarriers (P=0.03 for both). Ten at-risk relatives who completed the follow-up showed improvement in RSA - planned future (P=0.01) with respect to baseline.

DISCUSSION

Our case series showed that at-risk individuals undergoing predictive testing showed benefit on personal life and no detrimental impact on a broad range of psychological outcomes. Higher social skills and lower internal health locus of control in carriers may be an early psychological correlate of preclinical dementia.

Huntington's disease influences employment before and during clinical manifestation: A systematic review

Huntington's disease (HD) is an inherited neurodegenerative disease. People at risk for HD can choose to get predictive testing years before the clinical onset. HD is characterized by motor, cognitive and psychiatric symptoms and has a mean age at onset between 30 and 50 years, an age at which people are usually still working. This systematic review focuses on summarizing which disease-specific characteristics influence employment and working capacity in HD. Twenty-three studies were identified and showed that while employment and working capacity in HD are negatively influenced by cognitive decline and motor impairments, apathy already plays a role in the prodromal stage. Moreover, the influence of HD transcends the clinical manifestation of the disease, as some people at risk are already experiencing the impact of HD on employment through fear of or actual genetic discrimination. Employment and working capacity are not influenced by predictive testing for HD in and of itself.

Considerations regarding a diagnosis of Alzheimer's disease before dementia: a systematic review

BACKGROUND

The NIA-AA research framework proposes a purely biological definition of Alzheimer's disease (AD). This implies that AD can be diagnosed based on biomarker abnormalities, irrespective of clinical manifestation. While this brings opportunities, it also raises challenges. We aimed to provide an overview of considerations regarding the disclosure of AD pathology before the onset of dementia.

METHODS

A systematic literature review was conducted and reported according to PRISMA guidelines. We searched PubMed, Embase, APA PsycINFO, and Web of Science Core Collection (on 10 December 2020) for references on conveying AD biomarker results to individuals without dementia. Our query combined variations on the terms Alzheimer's disease, disclosure, or diagnosis, preclinical or prodromal, and biomarkers. Two reviewers independently screened the resulting 6860 titles and abstracts for eligibility and examined 162 full-text records for relevance. We included theoretical articles in English, on communicating amyloid and/or tau results to individuals with mild cognitive impairment, subjective cognitive decline, or normal cognition. MAXQDA-software was used for inductive data analysis.

RESULTS

We included 27 publications. From these, we extracted 26 unique considerations, which we grouped according to their primary relevance to a clinical, personal, or societal context. Clinical considerations included (lack of) validity, utility, and disclosure protocols. Personal considerations covered psychological and behavioral implications, as well as the right to (not) know. Finally, societal considerations comprised the risk of misconception, stigmatization, and discrimination. Overall, views were heterogeneous and often contradictory, with emphasis on harmful effects.

CONCLUSIONS

We found 26 diverse and opposing considerations, related to a clinical, personal, or societal context, which are relevant to diagnosing AD before dementia. The theoretical literature tended to focus on adverse impact and rely on common morality, while the motivation for and implications of biomarker testing are deeply personal. Our findings provide a starting point for clinicians to discuss biomarker-based diagnosis with their patients, which will become even more relevant in light of the conditional approval of a first disease-modifying drug for AD.

"I have to start learning how to live with becoming sick": A scoping review of the lived experiences of people with Huntington's disease

Person-centered care (PCC) is recognized as a key component of the delivery of quality healthcare and a model for healthcare systems worldwide. The experience of illness through a person's perspective is one domain defining PCC contributing to a growing interest in examining the lived experiences of illness. This scoping review sought to examine what is known from the existing literature about the lived experiences of persons gene-positive for or living with Huntington's disease (HD) as described in their own voices and to outline prominent psychosocial themes of those experiences. Five databases were systematically searched and analyzed resulting in 19 publications for inclusion. Using a thematic analysis, five prominent psychosocial themes were identified: grappling with control, avoidance as an escape from realities, adaptation to new realities, managing emotions, and appreciation for life. Variation in themes existed across HD life stage of being undiagnosed or diagnosed with HD. The findings of this review demonstrate that individuals who are gene-positive for or living with HD require support well beyond the disclosure of genetic testing and that it may be beneficial for healthcare providers to consider where along the life stage trajectory a person affected by HD may be to ensure the delivery of quality PCC.

Classification using fractional anisotropy predicts conversion in genetic frontotemporal dementia, a proof of concept

Frontotemporal dementia is a highly heritable and devastating neurodegenerative disease. About 10–20% of all frontotemporal dementia is caused by known pathogenic mutations, but a reliable tool to predict clinical conversion in mutation carriers is lacking. In this retrospective proof-of-concept case-control study, we investigate whether MRI-based and cognition-based classifiers can predict which mutation carriers from genetic frontotemporal dementia families will develop symptoms (‘convert’) within 4 years. From genetic frontotemporal dementia families, we included 42 presymptomatic frontotemporal dementia mutation carriers. We acquired anatomical, diffusion-weighted imaging, and resting-state functional MRI, as well as neuropsychological data. After 4 years, seven mutation carriers had converted to frontotemporal dementia (‘converters’), while 35 had not (‘non-converters’). We trained regularized logistic regression models on baseline MRI and cognitive data to predict conversion to frontotemporal dementia within 4 years, and quantified prediction performance using area under the receiver operating characteristic curves. The prediction model based on fractional anisotropy, with highest contribution of the forceps minor, predicted conversion to frontotemporal dementia beyond chance level (0.81 area under the curve, family-wise error corrected P = 0.025 versus chance level). Other MRI-based and cognitive features did not outperform chance level. Even in a small sample, fractional anisotropy predicted conversion in presymptomatic frontotemporal dementia mutation carriers beyond chance level. After validation in larger data sets, conversion prediction in genetic frontotemporal dementia may facilitate early recruitment into clinical trials.

Predictive testing for neurodegenerative diseases in the age of next-generation sequencing

The availability and cost of next-generation sequencing (NSG) now allow testing large numbers of genes simultaneously. However, the gold standard for predictive testing has been to test only for a known family mutation or confirmed family disease. The goal of this study was to investigate the psychological impact of predictive testing for autosomal dominant neurodegenerative diseases without a known family mutation using next-generation sequencing panels compared to single-gene testing of a known family mutation. Fourteen individuals from families with a known mutation and 10 individuals with unknown family mutations participated. Participants completed questionnaires on demographics, genetic knowledge, and psychological measures of anxiety, depression, perceived personal control, rumination, and intolerance to uncertainty at baseline and 1 and 6 months after receiving results. Decision regret was measured 1 and 6 months after receiving results. Participants completed a modified Huntington disease genetic testing protocol with genetic counseling and neurological and psychological evaluation. Genetic testing of either the known family mutation or an NGS panel of neurodegenerative disease genes was performed. Semi-structured interviews were performed at 6 months post-results about their experience. Two-sample t tests were performed on data collected at each time point to identify significant between-group differences in demographic variables, baseline psychological scores, and baseline genetic knowledge scores. Within-group change over time was assessed by a mixed-effects model. Results of this study indicate that NGS panels for predictive testing for neurodegenerative disease are safe and beneficial to participants when performed within a modified HD protocol. Though significant differences in psychological outcomes were found, these differences may have been driven by genetic results and baseline psychological differences between individuals within the groups. Participants did not regret their decision to test and were largely pleased with the testing protocol.

Cardiovascular health, genetic risk, and risk of dementia in the Framingham Heart Study

OBJECTIVE

To determine the joint role of ideal cardiovascular health (CVH) and genetic risk on risk of dementia.

METHODS

We categorized CVH on the basis of the American Heart Association Ideal CVH Index and genetic risk through a genetic risk score (GRS) of common genetic variants and the APOE ε4 genotype in 1,211 Framingham Heart Study (FHS) offspring cohort participants. We used multivariable Cox proportional hazards regression models to examine the association between CVH, genetic risk, and incident all-cause dementia with up to 10 years of follow-up (mean 8.4 years, 96 incident dementia cases), adjusting for age, sex, and education.

RESULTS

We observed that a high GRS (>80th percentile) was associated with a 2.6-fold risk of dementia (95% confidence interval [CI] of hazard ratio [HR] 1.23-5.29; p = 0.012) compared with having a low GRS (<20th percentile); carrying at least 1 APOE ε4 allele was associated with a 2.3-fold risk of dementia compared with not carrying an APOE ε4 allele (95% CI of HR 1.49-3.53; p = 0.0002), and having a favorable CVH showed a 0.45-fold lower risk of dementia (95% CI of HR 0.20-1.01; p = 0.0527) compared to having an unfavorable CVH when all 3 components were included in the model. We did not observe an interaction between CVH and GRS (p = 0.99) or APOE ε4 (p = 0.16).

CONCLUSIONS

We observed that both genetic risk and CVH contribute additively to dementia risk.

Genetic testing for Alzheimer's disease: trends, challenges and ethical considerations

PURPOSE OF REVIEW

Advances in personal genomics have made predictive genetic testing increasingly popular. The purpose of this review is to examine and summarize recent literature regarding the ethical concerns and considerations surrounding genetic testing for Alzheimer's disease.

RECENT FINDINGS

Four basic bioethical principles can be applied in the context of genetic testing: autonomy, nonmaleficence, beneficence and justice. The concepts of clinical validity, clinical utility and personal utility are also necessary for the ethical deliberation of genetic testing for Alzheimer's disease. Ethical considerations can differ among three distinct settings present in the literature: research, clinical and direct-to-consumer services. Studies have found that the negative psychosocial impact of genetic test results on the individual is limited, but emphasize the importance of pre/posttesting genetic counselling.

SUMMARY

The literature should ideally inform policy-making around genetic testing. There exists an urgent need for regulation, particularly in the direct-to-consumer (DTC) market, since interest for testing in this context is rapidly growing. Standardized protocols for disclosure should be developed, and there is a need to find ways to meet the growing need for genetic counselling. Importantly, comprehensive, evidence-based regulation requires that research be conducted in different contexts with more diverse participants.