Genetic Susceptibility MHC Related Not mhc related HLA-DR1, 2, 3, 4 C1q deficiency(rare but highest risk Alleles of HLA-DRB1 IRF5 Chromosome 1 region 1q41-43(PARP), and stat4 region 1q23(FCYRIIA, FcYRIIIA c2·c4 deficiency IL-10, IL-6 and MBL polymorphisms TNF-a polymorphisms Chromosome 8.p23.1: reduced expression of BLK and increased expression of C8orf13 (B cell tyrosine kinase), chromosome 16p11.22: integrin a genes IGAM-ITGAX B cell gene BANK1 x chromosome-linked gene IRAK1Genetic Susceptibility MHC Related • HLA-DR1, 2, 3, 4 • Alleles of HLA-DRB1, IRF5, and STAT4 • C2 - C4 deficiency • TNF- polymorphisms Not MHC Related • C1q deficiency (rare but highest risk) • Chromosome 1 region 1q41-43 (PARP), region 1q23 (FcγRIIA, FcγRIIIA) • IL-10, IL-6 and MBL polymorphisms • Chromosome 8.p23.1: reduced expression of BLK and increased expression of C8orf13 (B cell tyrosine kinase), chromosome 16p11.22: integrin  genes IGAM-ITGAX • B cell gene BANK1 • X chromosome-linked gene IRAK1