Providing genetic testing and genetic counseling for Parkinson's disease to the community.

PURPOSE: To evaluate the feasibility and impact of offering genetic testing and counseling to patients with Parkinson's disease (PD), with the potential to enroll in gene-targeted clinical trials and improve clinical care. METHODS: A multicenter, exploratory pilot study at 7 academic hospital sites in the United States tracked enrollment and randomized participants to receive results and genetic counseling at local sites or by genetic counselors, remotely. Follow-up surveys measured participant/provider satisfaction, knowledge, and psychological impact. RESULTS: From September 5, 2019 to January 4, 2021, 620 participants were enrolled and 387 completed outcome surveys. There were no significant differences in outcomes between local and remote sites, with both arms reporting high knowledge and satisfaction scores (>80%). Notably, 16% of those tested had reportable PD gene variants (pathogenic/likely pathogenic/risk allele). CONCLUSION: Local clinicians, as well as genetic counselors, with educational support as needed, can effectively return genetic results for PD as we observed favorable outcome measures in both groups. Increasing access to PD genetic testing and counseling is urgent; this can inform future efforts to integrate genetic testing and counseling into clinical care for all those with PD.

International Genetic Testing and Counseling Practices for Parkinson's Disease.

BACKGROUND: There is growing clinical and research utilization of genetic testing in Parkinson's disease (PD), including direct-to-consumer testing. OBJECTIVES: The aim is to determine the international landscape of genetic testing in PD to inform future worldwide recommendations. METHODS: A web-based survey assessing current practices, concerns, and barriers to genetic testing and counseling was administered to the International Parkinson and Movement Disorders Society membership. RESULTS: Common hurdles across sites included cost and access to genetic testing, and counseling, as well as education on genetic counseling. Region-dependent differences in access to and availability of testing and counseling were most notable in Africa. High-income countries also demonstrated heterogeneity, with European nations more likely to have genetic testing covered through insurance than Pan-American and Asian countries. CONCLUSIONS: This survey highlights not only diversity of barriers in different regions but also the shared and highly actionable needs for improved education and access to genetic counseling and testing for PD worldwide. © 2023 International Parkinson and Movement Disorder Society.

Genetic Testing in Parkinson's Disease.

Genetic testing for persons with Parkinson's disease is becoming increasingly common. Significant gains have been made regarding genetic testing methods, and testing is becoming more readily available in clinical, research, and direct-to-consumer settings. Although the potential utility of clinical testing is expanding, there are currently no proven gene-targeted therapies, but clinical trials are underway. Furthermore, genetic testing practices vary widely, as do knowledge and attitudes of relevant stakeholders. The specter of testing mandates financial, ethical, and physician engagement, and there is a need for guidelines to help navigate the myriad of challenges. However, to develop guidelines, gaps and controversies need to be clearly identified and analyzed. To this end, we first reviewed recent literature and subsequently identified gaps and controversies, some of which were partially addressed in the literature, but many of which are not well delineated or researched. Key gaps and controversies include: (1) Is genetic testing appropriate in symptomatic and asymptomatic individuals without medical actionability? (2) How, if at all, should testing vary based on ethnicity? (3) What are the long-term outcomes of consumer- and research-based genetic testing in presymptomatic PD? (4) What resources are needed for clinical genetic testing, and how is this impacted by models of care and cost-benefit considerations? Addressing these issues will help facilitate the development of consensus and guidelines regarding the approach and access to genetic testing and counseling. This is also needed to guide a multidisciplinary approach that accounts for cultural, geographic, and socioeconomic factors in developing testing guidelines. © 2023 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

A cross-sectional survey of genetic counselors providing carrier screening regarding GBA variants and Parkinson disease susceptibility.

PURPOSE: Adult-onset disease risks associated with carriers of recessive disease have and will continue to be identified. As carrier screening becomes more broadly utilized, providers face the dilemma of whether they should discuss these risks during discussions with prospective parents. This study aimed to understand whether preconception/prenatal genetic counselors (PPGCs) were aware of the risk of Parkinson disease in carriers of, and persons with, Gaucher disease and the reasons behind choosing whether to discuss this risk with patients. METHODS: Eligible participants included board-certified or board-eligible genetic counselors who had counseled preconception/prenatal patients within the past 3 years. An online survey was distributed via the National Society of Genetic Counselors in November of 2017. RESULTS: One hundred twenty genetic counselors completed the quantitative survey, distributed in Fall of 2017. While the majority of respondents knew of the Gaucher-related Parkinson's link (n = 78; 65%), just over one-third reported discussing it in preconception/prenatal settings (n = 30; 38.5%). Respondents reported discussing these links more consistently when disclosing positive results or when the patient/family approached the topic. Respondents cited the lack of professional guidelines as one of the main reasons for not discussing the link. CONCLUSION: These results highlight an inconsistency in PPGCs' discussions of the Parkinson's risk in Gaucher disease carriers, and the need to develop guidelines regarding these issues to help standardize the care and education of patients.

The Role of Genetic Testing for Parkinson's Disease.

PURPOSE OF REVIEW: To describe current practices and attitudes about genetic testing for Parkinson's disease (PD) among neurologists, highlight the changing scene of genetic testing for PD, and provide guidance on facilitating PD genetic testing in a clinical practice. RECENT FINDINGS: Since the 1990s, researchers have discovered several major gene variants contributing to PD etiology. A large body of literature now exists supporting the frequency of these variants in different populations and their effects on phenotype and clinical course. Recently, clinical trials have emerged with therapies targeting genetic forms of PD, specifically LRRK2 and GBA. Despite this growing knowledge, genetic testing for PD is not typically offered by neurologists including movement disorder specialists. Neurologists express concerns about the financial and practical issues of genetic testing as well as the potential impact on their patients. Researchers and specialists in the field are questioning this hesitation as clinical utility and consumer demand increase. Consideration of genetic testing for PD is shifting, as we enter a new era of precision medicine and gain clinical knowledge about PD. Barriers to testing, as perceived by clinicians, can be overcome with education, support, and involvement of multiple stakeholders with the goal of making PD genetic testing accessible to all patients.

Outcomes of genetic test disclosure and genetic counseling in a large Parkinson's disease research study.

Genetic testing for Parkinson's disease (PD) is growing as interventional clinical trials begin to enroll participants with PD who carry pathogenic variants in the LRRK2 or GBA genes. However, the impact of receiving genetic test results and the satisfaction with receiving genetic counseling among PD populations have not yet been studied. The purpose of this study was to evaluate (1) the psychological impact of genetic testing for PD and (2) satisfaction with genetic counseling. Surveyed participants (N = 875) were individuals with PD or at risk of developing PD, initially recruited for the Parkinson's Progression Marker Initiative (PPMI) study and currently enrolled in the Widespread Recruitment Initiative (WRI) at Indiana University. Individuals were surveyed following genetic test disclosure and genetic counseling regarding results from targeted testing for pathogenic variants in the LRRK2 and GBA genes. Participants were surveyed via two tools: a modified version of the Multidimensional Impact of Cancer Risk Assessment Survey (M-MICRA), which measured the psychological impact of genetic testing and the Genetic Counseling Satisfaction Survey (GCSS). Participants were divided into affected/unaffected and variant positive/negative groups for subset analyses. The majority of participants had favorable M-MICRA scores and were satisfied with the disclosure of the genetic test results and genetic counseling for PD. However, participants with PD and those with pathogenic variants had less favorable M-MICRA scores and lower satisfaction scores compared to those without disease or pathogenic variants. This information is valuable to providers performing genetic testing of and genetic counseling to people and families affected with PD. Individuals with PD and individuals with pathogenic variants may benefit from additional interventions.

Evaluation and classification of severity for 176 genes on an expanded carrier screening panel.

BACKGROUND: Disease severity is important when considering genes for inclusion on reproductive expanded carrier screening (ECS) panels. We applied a validated and previously published algorithm that classifies diseases into four severity categories (mild, moderate, severe, and profound) to 176 genes screened by ECS. Disease traits defining severity categories in the algorithm were then mapped to four severity-related ECS panel design criteria cited by the American College of Obstetricians and Gynecologists (ACOG). METHODS: Eight genetic counselors (GCs) and four medical geneticists (MDs) applied the severity algorithm to subsets of 176 genes. MDs and GCs then determined by group consensus how each of these disease traits mapped to ACOG severity criteria, enabling determination of the number of ACOG severity criteria met by each gene. RESULTS: Upon consensus GC and MD application of the severity algorithm, 68 (39%) genes were classified as profound, 71 (40%) as severe, 36 (20%) as moderate, and one (1%) as mild. After mapping of disease traits to ACOG severity criteria, 170 out of 176 genes (96.6%) were found to meet at least one of the four criteria, 129 genes (73.3%) met at least two, 73 genes (41.5%) met at least three, and 17 genes (9.7%) met all four. CONCLUSION: This study classified the severity of a large set of Mendelian genes by collaborative clinical expert application of a trait-based algorithm. Further, it operationalized difficult to interpret ACOG severity criteria via mapping of disease traits, thereby promoting consistency of ACOG criteria interpretation.

The Promise and Pitfalls of Facebook Advertising: a Genetic Counselor's Perspective.

Facebook advertising is a powerful tool for increasing the outreach and recruitment of research participants. We describe our experience as genetic counselors within the context of an internet-based research study, recruiting subjects for a Parkinson disease (PD) biomarker study.

Connecting Gaucher and Parkinson Disease: Considerations for Clinical and Research Genetic Counseling Settings.

There are multiple autosomal recessive disorders in which carriers may be at risk for other diseases. This observation calls into question the previous understanding that carriers of autosomal recessive disorders escape clinical consequences. We also know that childhood genetic conditions may have adult disease counterparts (Zimran et al., The Israel Medical Association Journal: IMAJ, 16(11), 723-724, 2014). Individuals who have Gaucher disease and carriers of the disorder are at increased risk for a seemingly unrelated and complex neurological condition, Parkinson disease. Parkinson disease is, in part, caused by the same mutations in the GBA gene that lead to Gaucher disease, and the two conditions are thought to have shared pathophysiology. Briefly reviewed are how these two diseases historically became linked, where their paths cross, potential problems and considerations in disclosure of the link, and current guidelines and research in this area. Genetic counseling experience with a large Parkinson disease cohort is used as a starting point to question the state of clinical and nonclinical practice in disclosing this unusual connection We conclude that more research and discussion are needed to inform practice regarding the crossroads of Gaucher and Parkinson disease.

Factors Influencing Patient Disclosure of Parkinson's Disease Genetic Testing Results to Relatives.

BACKGROUND: Persons with Parkinson's disease (PD) who have received genetic test results are faced with the decision of whether, and how, to share that information with family. Studies in other specialties have shown high rates of disclosure motivated by a sense of responsibility. Rates of, and attitudes surrounding, disclosure have yet to be reported in this population. OBJECTIVES: To explore the disclosure practices and motivations of patients with PD regarding genetic test results, allowing insight to guide genetic counseling and navigation of test result discussions. METHODS: A cross-sectional online survey was distributed to adults with PD and previous genetic test results. Survey questions assessed demographics, genetic testing results and delivery, sharing behaviors, perceptions of PD, and motivations and barriers to family disclosure. RESULTS: Among respondents, 88.9% shared results with at least one family member, most often a child (73.5%) or sibling (65.4%). Seventy-four percent reported sharing results with someone outside of their family, most frequently a friend (88.4%). The most common motivation for disclosure was the perception that family members would want to know. Barriers to disclosure were lack of close relationships, understanding results, and perceived utility. CONCLUSIONS: Disclosure rates in this PD population were consistent with those in previously reported populations. Motivations were anchored in perceptions of utility and family desire for information, suggesting a need to adjust patient education to improve retention and to explore family dynamics and perceptions of results.

The commercial genetic testing landscape for Parkinson's disease.

INTRODUCTION: There have been no specific guidelines regarding which genes should be tested in the clinical setting for Parkinson's disease (PD) or parkinsonism. We evaluated the types of clinical genetic testing offered for PD as the first step of our gene curation. METHODS: The National Institutes of Health (NIH) Genetic Testing Registry (GTR) was queried on 12/7/2020 to identify current commercial PD genetic test offerings by clinical laboratories, internationally. RESULTS: We identified 502 unique clinical genetic tests for PD, from 28 Clinical Laboratory Improvement Amendments (CLIA)-approved clinical laboratories. These included 11 diagnostic PD panels. The panels were notable for their differences in size, ranging from 5 to 62 genes. Five genes for variant query were included in all panels (SNCA, PRKN, PINK-1, PARK7 (DJ1), and LRRK2). Notably, the addition of the VPS35 and GBA genes was variable. Panel size differences stemmed from inclusion of genes linked to atypical parkinsonism and dystonia disorders, and genes in which the link to PD causation is controversial. CONCLUSION: There is an urgent need for expert opinion regarding which genes should be included in a commercial laboratory multi-gene panel for PD.

Genetic Testing for Parkinson Disease: Are We Ready?

PURPOSE OF REVIEW: With the advent of precision medicine and demand for genomic testing information, we may question whether it is time to offer genetic testing to our patients with Parkinson disease (PD). This review updates the current genetic landscape of PD, describes what genetic testing may offer, provides strategies for evaluating whom to test, and provides resources for the busy clinician. RECENT FINDINGS: Patients with PD and their relatives, in various settings, have expressed an interest in learning their PD genetic status; however, physicians may be hesitant to widely offer testing due to the perceived low clinical utility of PD genetic test results. The rise of clinical trials available for patients with gene-specific PD and emerging information on genotype-phenotype correlations are starting to shift this discussion about testing. SUMMARY: By learning more about the various genetic testing options for PD and utility of results for patients and their care, clinicians may become more comfortable with widespread PD genetic testing in the research and clinical setting.