SUMMARY
# LRRK2/GBA Mutation Carrier Resilience — Why Some Carriers Never Develop PD
## Background and Rationale
Parkinson's Disease (PD) affects 1-2% of individuals over 65, with genetic mutations in LRRK2 and GBA significantly increasing disease risk. LRRK2 G2019S mutations confer 30-74% lifetime PD risk, while GBA mutations increase risk 5-10 fold. However, substantial numbers of mutation carriers remain disease-free throughout their lives, suggesting the existence of protective factors that could be
METHODOLOGY NOTES
Phase 1 (Months 1-6): Recruit 500 asymptomatic LRRK2/GBA carriers (aged 50-80, mutation-positive >10 years, MDS-UPDRS-III <6), 300 symptomatic carriers, and 400 matched controls through international consortiums. Perform comprehensive clinical phenotyping including MDS-UPDRS, MoCA, detailed family/medical history, and lifestyle questionnaires. Collect biospecimens: blood (50mL), saliva (5mL), stool samples, and CSF (optional, 15mL). Phase 2 (Months 4-18): Conduct whole genome sequencing (30x coverage) using Illumina NovaSeq platform. Perform untargeted metabolomics via LC-MS/MS, proteomics using TMT-labeling and mass spectrometry, and methylation analysis using EPIC arrays. Analyze microbiome composition via 16S rRNA sequencing and shotgun metagenomics. Execute neuroimaging protocols including DAT-SPECT, structural/diffusion MRI, and resting-state fMRI. Phase 3 (Months 12-36): Implement machine learning algorithms (random forest, neural networks) for multi-omics integration and biomark