PPP3R1 and systemic lupus erythematosus: At FDR significance (PFDR < .05), MR analysis revealed 8 protein–SLE pairs (Table 1, Figs. 2A and B and 3), including calcineurin A (PPP3CA;PPP3R1), intercellular adhesion molecular 1 (ICAM-1) in the plasma; Fc-gamma-RIIb (FCG2B), soluble intercellular adhesion molecule 1 (sICAM-1), Nidogen 2 (NID2), N-terminal pro-B-type natriuretic peptide (N-terminal pro-BNP), Layilin and Prekallikrein in the CSF.