GBPDC: Gut-Brain in PD Consortium Master Protocol

The objectives of the master protocol are to establish a common platform that: (1) assures the collection, integration, and analysis of a set of uniformly collected data across all participating centers, and (2) follows the objective of the Gut-Brain Parkinson's Disease Consortium (GBPDC) with the goal "to enhance our understanding of the temporal onset of GI symptoms in PD and changes in gut-brain communication that can be used to leverage the potential role of the GI tract in the pathogenesis and progression of PD and to improve patient diagnosis, care, and outcomes." Primary Objective 1\. To collect prospective cross-sectional and longitudinal participant biospecimens with temporally coordinated evaluations of GI and neurological symptoms and functions to better characterize the phenotype of people with PD versus those without. Secondary Objectives 1. To elucidate the biological processes and pathways relevant to the role of the GI tract in the pathogenesis and progression of PD. 2. To characterize GI symptoms, pathology, and gut-brain communication in PD to detect early and longitudinal changes in gut function and activity that correspond to the development or progression of PD. Exploratory Objectives 1. To identify possible novel gut-based biomarkers (functional, molecular, etc.), diagnostic tools, and therapeutic targets. 2. To investigate the impact of neuroimmune interactions and other pathways in the GI tract on gut-brain communication and PD risk. In conjunction with clinical, social, and environmental characterization, biospecimen collection within the GBPDC master protocol will provide the opportunity to probe and characterize the pathophysiologic underpinnings of the gut-brain axis in PD, refine existing biomarker testing for PD, and identify new biomarkers that could allow early detection of PD or new targets for treatment. Duke University will serve as the biorepository for the GBPDC. Participants and study site personnel will collect, process, and ship biospecimens according to the GBPDC Biorepository Manual of Procedures using standard kits assembled specifically for the GBPDC master protocol. Biospecimens will be shipped from the study sites to the GBPDC central biorepository at Duke University for accessioning, storage, tracking, and subsequent distribution for use in approved future research. Throughout the conduct of the master protocol, a portion of the biospecimens received by the GBPDC central biorepository will be transferred to the NIDDK biorepository for approved research use. Any biospecimen aliquots remaining at the GBPDC central biorepository at the termination of the GBPDC program will be transferred to the NIDDK biorepository. Statistical Design This is a prospective, observational, longitudinal cohort study designed to characterize gut-brain communication in Parkinson's Disease. The study employs a longitudinal design, including cross-sectional analyses of baseline data, to evaluate gastrointestinal and neurological functions in participants with PD compared to household controls and a prodromal cohort, as well as comparisons among PD severity subgroups. Study Design Features: * Multi-center observational study across 5 GNRCs * Three participant cohorts: people with PD, people with prodromal features of PD, and household controls. The PD cohort will be further classified as mild, moderate, or severe PD. * Longitudinal design with assessments at baseline, 6, 12, 18, and 24 months * Comprehensive biospecimen collection coordinated with clinical assessments * Household control design where controls are matched to people with PD when available