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.
Summary
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.
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.
We have greater knowledge about the genetic contributions to Parkinson’s disease (PD) with major gene discoveries occurring in the last few decades and the identification of risk alleles revealed by ...genome-wide association studies (GWAS). This has led to increased genetic testing fueled by both patient and consumer interest and emerging clinical trials targeting genetic forms of the disease. Attention has turned to prodromal forms of neurodegenerative diseases, including PD, resulting in assessments of individuals at risk, with genetic testing often included in the evaluation. These trends suggest that neurologists, clinical geneticists, genetic counselors, and other clinicians across primary care and various specialties should be prepared to answer questions about PD genetic risks and test results. The aim of this article is to provide genetic information for professionals to use in their communication to patients and families who have experienced PD. This includes up-to-date information on PD genes, variants, inheritance patterns, and chances of disease to be used for risk counseling, as well as insurance considerations and ethical issues.
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.
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.
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.
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.
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.
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).
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.
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