Additional Study Information: FoxBioNet ECV-004 is an observational study sponsored by the Michael J. Fox Foundation for Parkinson's Research. The purpose of this study is to investigate a gene called LRRK2. Mutations in the LRRK2 gene are associated with Parkinson's disease (PD), and mutation carriers have greater LRRK2 protein activity. The goal of this study is to identify reliable markers of LRRK2 activity in human cerebrospinal fluid. This study is enrolling volunteers aged 30 and older, with and without Parkinson's disease, with and without LRRK2 mutations, to undergo a lumbar puncture to collect cerebrospinal fluid and have some blood drawn. The study visit will take approximately 4 hours and participants will receive a prepaid debit card with $200 upon completion.