In our previous studies, we identified CFH, HLA-DRA, HLA-DRB1, PXK, BLK, UBE2L3 and MTMR3 as shared loci between IgAN and systemic lupus erythematosus (SLE)/LN based on GWAS on Chinese populations, highlighting pathways including MHC class-II antigen presentation, complement regulation, signaling by the BCR, autophagy, and ubiquitin/proteasome-dependent degradation in the pathogenesis of these two complex diseases4, 5, 6, 7, 8, 9. The gene discussed is BLK; the disease is systemic lupus erythematosus.