The Parkinson’s Progression Markers Initiative (PPMI) offers the unique opportunity to address key gaps in knowledge regarding clinical, biomarker and genetic differences in LRRK2-associated parkinsonism with and without evidence of asyn aggregates, given that the cohort has had in vivo assessment of asyn aggregates in CSF as well as extensive longitudinal phenotyping in a relatively large number of cases. The gene discussed is LRRK2; the disease is Parkinson disease.