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.