Recent studies have identified the following genes as affecting susceptibility to SLE in Japanese: human leukocyte antigen DRB1 (HLA-DRB1) *15∶01, interferon regulatory factor 5 (IRF5) rs41298401C, signal transducer and activator of transcription-4 (STAT4) rs7574865T, B lymphoid tyrosine kinase (BLK) rs13277113A, tumor necrosis factor alpha-induced protein 3 (TNFAIP3) rs2230926G and TNFAIP3-interacting protein 1 (TNIP1) rs7708392C [5]–[10]. Here, STAT4 is linked to systemic lupus erythematosus.