Orange boxes denote steps of the workflow specific to the PPMI study while the purple box denotes validation phase analyses in additional sample series outside of PPMI. Abbreviations include: Parkinson’s Progression Marker Initiative (PPMI), Parkinson’s Disease Biomarkers Program (PDBP), Parkinson’s Associated Risk Study (PARS), 23andMe, Longitudinal and Biomarker Study in PD (LABS-PD), and Morris K. Udall Parkinson’s Disease Research Center of Excellence (Penn-Udall), University of Pennsylvania Smell Identificaiton Test (UPSIT), genetic risk score (GRS), subjects with dopamine transporter imaging scans showing no evidence of dopaminergic deficit (SWEDD), area under the curve (AUC).