Eight proteins were significantly changed in MDD after controlling for multiple comparisons (FDR < 0.05, Additional file 2: Table S1), including GNB4, RAC1, and CNTFR (up) and LY6H, CNTN1, DPYSL4, LAP3, and SLC17A7 (down). Here, DPYSL4 is linked to major depressive disorder.