The poster Parkinson’s Progression Markers Initiative (PPMI): Defining PD biology to accelerate PD therapeutics provides an overview of the PPMI study to date, including an update on the efforts of the expanded protocol, enrollment, and a description of the staged-risk paradigm. Most significantly it describes synuclein as a PD biomarker and proposes a biological definition of disease (Neuronal Synuclein Disease NSD) and an integrated biologic/clinical staging of NSD-ISS.