EVALUATION OF AN ASSOCIATION BETWEEN RS5219 POLYMORPHISM OF KCNJ11 GENE AND THE RISK OF TYPE 2 DIABETES MELLITUS

Abstract

Background: Type 2 diabetes mellitus (T2DM) represents from 90 to 95% of all diabetes and usually occurs in obese individuals above 40 years of age, is highly prevalent, associated with high morbidity and mortality from complications involving, first of all, the cardiovascular system. The risk of T2DM is determined by combined effects of genetic and environmental factors. Genes associated with T2DM have been identified, including the gene of ATPdependent potassium channel (KCNJ11); the prevalence of its polymorphisms may have some regional characteristics.Aim: To study an association between rs5219 KCNJ11 gene polymorphisms and the risk of T2DM in the population of the Moscow Region.Materials and methods: The study involved 1050 subjects, including 311 men and 739 women, 139 of whom (17 men and 122 women) had T2DM. Genotyping of rs5219 KCNJ11 gene polymorphisms was performed with the use of allele-specific amplification, the real-time detection and TaqMan-probes complementary to the DNA polymorphism sites.Results: The analysis of rs5219 KCNJ11 polymorphism frequencies showed that 14.2% of patients had TT genotype, 44.8 – CT genotype, and 41.1% – normal (wild) CC genotype. The prevalence of the mutant T allele was 36.6%, that of the C allele – 63.4%. The frequency of the mutant T allele in patients with obesity (body mass index≥30 kg/m²) was not significantly different from that in patients without obesity (body mass index<30 kg/m²) (38.8% and 35.7%, respectively, odds ratio (OR) 1.14, 95% confidence interval (CI) 0.907–1.439, p=0.26). At the same time, energy expenditure at rest per kg of lean body mass was significantly lower in men who have rs5219 KCNJ11 gene polymorphism, both in homoand heterozygotes. The frequency of the T allele and TT genotype in diabetic patients was higher than in the control group. An association between TT genotype and the risk of T2DM was found (OR 2.35, CI 1.018–5.43, p=0.04).Conclusion: In the population of the Moscow Region, gene polymorphism rs5219 KCNJ11 contributes to the risk of developing T2DM which is most obvious and statistically significant in homozygotes.