Four previously reported loci of autoimmune diseases, including PTPN22 (rs6679677, rs2476601, rs2488457), STAT4 (rs3821236, rs7574865), C12orf30, and ADAD1-IL2-IL21 (rs17388568, rs13143866), and three novel loci including PTPN2 (rs1893217, rs7234029), COG6 (rs7993214), and ANGPT1 (rs1010824), were identified of association with oligoarthritis and polyarthritis RF-negative [77]. The gene discussed is IL21; the disease is autoimmune disease.