MOLECULAR AND GENETIC DIAGNOSTICS OF INFLAMMATORY BOWEL DISEASES

Background: In the last two decades, more attention has been paid to the development and implementation of molecular and genetic technologies for the diagnosis and prediction of the development and course of inflammatory bowel diseases (IBD). However, the published evidence on their diagnostic significance are rather controversial and equivocal that may be explained by some characteristics of their frequencies, differences in pathogenetic, clinical and diagnostic vales of the genetic polymorphisms in various countries and regions.Aim: To evaluate the frequency, clinical, diagnostic, and prognostic significance of the 3020insC and G2722С nucleotide polymorphisms of the CARD15 (NOD2) gene in Crohn's disease (CD) and ulcerative colitis (UC) in the Kemerovo Region of the Russian Federation.Materials and methods: The study included 144 patients with IBD (58 with CD, 86 with UC), and 44 patients without any gastrointestinal tract disorders in the control group. The 3020insC and 2722С allelic frequencies of the CARD15 gene were determined. All patients were of the Russian ethnicity and were living in the territory of the Kemerovo Region at the time of the study.Results: The frequency of the 3020insC allele of the CARD15 gene in CD patients was significantly higher than in those with UC (16% vs 3%, p < 0.001) and in the control group (5%, р = 0.04). The homozygous genotype of 3020insC/insC was found only in the CD patients. The carriage of the 3020insC allele was associated with an average 3.5-fold increase of the probability of CD development (odds ratio [OR] 3.6; 95% confidential interval [CI]: 1.3–10.3) and was not significantly linked to an increased risk of UC (OR 0.6; 95% CI: 0.1–2.5). The 3020insC allelic frequency in the pooled group of the patients with complicated CD variants (with stricture formation and penetrative) was significantly higher, compared to those with the luminal forms (79% vs 21%, р = 0.03) and with the penetrative CD forms compared to the luminal (50% vs 21%, р = 0.05). The 3020insC allele carriage in the CD patients was associated with a 3.3-fold increase in the risk of the penetrative forms of the disease (OR 3.3; 95% CI: 1.8–6.1) and with a 14-fold increase of the overall risk of the complicated CD variants (OR 14.1; 95% CI: 7.1–27.9). The 2722С allelic frequency in CD and UC patients and in the control group were not significantly differe