SNCA and Parkinson disease: Specifically, 3 increased protein abundance was significantly associated with an increased risk of PD, namely BAG3 (OR:1.588, 95% CI: 1.282–1.969, P = 2.37E-05), GPNMB (OR:1.642, 95% CI:1.368–1.972, P = 1.76E-05) and FCGR2A (OR:1.061, 95% CI:1.033–1.090, P = 1.76E-05), while the increased SNCA abundance significantly decreased PD risk (OR:0.418, 95% CI:0.354–0.494, P = 6.26E-25).