Our study sought to assess the role of α-synuclein-positive EVs and PAR levels in plasma as biomarkers of PD presence and progression and whether the combined determination of EVs (a putative surrogate of α-synuclein accumulation and impaired autophagy) and PAR (product of PARP-1 activity) better assesses PD pathobiology. Here, SNCA is linked to Parkinson disease.