NOD1/CARD4(G796A) and NOD2/CARD15(R702W, G908R and L1007fsinC) polymorphisms associated with Crohn's disease in Iraqi patients

Inflammatory bowel disease (IBD) applies to two main forms of chronic relapsing inflammatory intestinal disorders: Crohn's disease (CD), Ulcerative colitis (UC). CD requires an irregular immune reaction that induces intense inflammation. The cause of CD disease is not yet fully known; previous research, however, indicated inflammation of the intestines elevated or continues due to inappropriate immune responses due to associations between genetic factors, intestinal microbiota, and environmental factors contributing to the production of IBD. This study aimed to investigate predisposing genes, single nucleotide Polymorphisms (SNPs) NOD1/CARD4 and NOD2/CARD15) with CD in Iraqi patients. The common NOD1 (G796A) SNP and NOD2 SNPs R702W, G908R and L1007fsinC for NOD2 SNPs were selected. Thirty Iraqi citizens with a recognized diagnosis of CD and twenty apparently healthy controls were included in the study from November 2019 to December 2020; the common NOD1 and NOD2 polymorphisms have been screened by the polymerase chain reaction/restriction analysis length polymorphism (PCR/RFLP). The results of the current investigation for NOD1 polymorphism in studied patients and controls, the allelic and genotypic data show a highly significant association of G796A SNPs in the NOD1 with Crohn's disease, GA percentage was 56.67% in patients as compared to controls genotype was (0.00%). Furthermore, the G allele was more common in Crohn's patients than the A allele 0.72 vs. 0.28. Also, the allelic and genotypic frequency distribution of the studied NOD2 SNPs in the current study were (R702W, G908R, and L1007fs) in Iraqi patients, and controls revealed a highly significant connection between the G908R SNP with Crohn's disease susceptibility. The proportion of the genotype GC was 30% in patients while 0% in the control group, the frequency of the G allele was 0.85 vs 0.15 respectively, which was more than the frequency of the A allele. There were no significant changes in genotypic and allelic frequencies of the R702W and L1007fs SNPs in Iraqi Crohn's disease patients. The present study concluded that the NOD1 SNP of allelic and genotypic data show a highly significant association of G796A with a predisposition to Crohn's disease in Iraqi patients. And the NOD2 SNPs of G908R were also revealed to be highly effective. While the other studied SNPs were R702W and L1007fsinsC of NOD2, which showed no significant changes in the allelic and genotypic frequencies of the SNPs with Crohn's disease Iraqi patients. Keywords: Inflammatory bowel disease, Crohn's disease, NOD1/CARD4, NOD2/CARD15, polymorphisms.