rs12537284

This review article by Ota and Kuwana synthesizes genetic studies on systemic sclerosis (SSc), a complex autoimmune disease. Multiple genetic association studies, including GWAS and candidate gene approaches, have identified SSc susceptibility genes primarily involved in innate immunity (IRF4, IRF5, IRF7, IRF8, TNFAIP3), adaptive immune response (TNFSF4, CD247, PTPN22, CSK, STAT4, BLK), IL-12 signaling (IL-12A, IL-12RB1, IL-12RB2, TYK2), apoptosis/autophagy (ATG5, GSDMA, GSDMB, NOTCH4), and vascular homeostasis/fibrosis (PPARG). The review emphasizes that identified risk variants are predominantly located in non-coding regulatory regions and influence gene expression rather than protein structure.

This is a comprehensive review of genetic factors in systemic sclerosis (SSc), a complex autoimmune disease. The review synthesizes findings from candidate gene analysis and genome-wide association studies identifying numerous SNPs and genetic variants associated with SSc susceptibility, primarily in genes involved in innate immunity (IRF4, IRF5, IRF7, IRF8, TNFAIP3), adaptive immunity (TNFSF4, PTPN22, STAT4, BLK, PRDM1), and cell death pathways (ATG5, DNASE1L3, GSDMA/B, NOTCH4). HLA class II genes are associated with SSc-related autoantibodies rather than SSc itself, with DRB1 alleles carrying the FLEDR amino acid sequence critical for anti-topo I antibody responses.

This review updates knowledge on genetic factors in systemic sclerosis (SSc) susceptibility and disease expression. GWAS and candidate gene studies have identified multiple SSc-associated genetic variants primarily located in non-coding regions that influence gene expression through eQTL effects. Major risk genes include those involved in innate immunity (IRF4, IRF5, IRF7, IRF8, TNFAIP3), adaptive immune response (PTPN22, STAT4, TNFSF4, CD247), and cell death pathways (ATG5), while few genes directly involve fibrosis or vascular homeostasis. HLA class II genes associate with SSc-related autoantibodies rather than SSc itself. Multi-omics approaches are needed to characterize the complex molecular architecture and identify biomarkers.

Genome-wide association study of 116 children with cardiac neonatal lupus (116 cases, 3,351 controls) identified 17 significant SNPs in the HLA region at 6p21, with the strongest association at rs3099844 (OR 3.34, P=4.52×10⁻¹⁰) near the MICB gene. Non-HLA associations were found at rs743446 (21q22, OR 2.40, P=5.45×10⁻⁶), rs2403106 (12q21, OR 2.48, P=2.62×10⁻⁶), rs1391511 (10p15, OR 1.84, P=6.6×10⁻⁶), and rs1890645 (1q31, OR 2.98, P=3.52×10⁻⁶). Results suggest genetic polymorphisms in inflammatory and apoptotic pathways contribute to cardiac injury in fetuses exposed to maternal anti-Ro/SSA antibodies.

A meta-analysis of 4,107 type 2 diabetes cases and 5,187 controls from three GWA studies found no evidence that common variants altering circulating inflammatory protein levels (IL-18, IL-6R, CRP, IL1RN, PAI1, MIF) or variants predisposing to autoimmune diseases (type 1 diabetes, rheumatoid arthritis, Crohn's disease, celiac disease, multiple sclerosis, SLE) are associated with type 2 diabetes risk. For example, rs2250417 in IL18 showed OR=1.00 (95% CI 0.99-1.03) versus the expected OR of ~1.15 if inflammation were causal, suggesting inflammatory markers are likely secondary rather than causative in type 2 diabetes.