Endocrine Abstracts

Aim: To investigate the possible association of the FTO gene rs9939609 polymorphism with different disorders of carbohydrate metabolism in residents of the Republic of Tatarstan.

Materials and methods: A total of 237 patients with a single history of hyperglycemia were examined. They underwent an oral glucose tolerance test on a BS-200E Mindray analyzer. 198 patients from the whole cohort had various disorders of carbohydrate metabolism, so they were included in the study. The patients were divided into several groups: 110 people with type 2 diabetes mellitus (DM2), 46 with hyperinsulinism, 29 with impaired glucose tolerance, and 13 with impaired fasting glycemia. DNA was isolated from whole blood, followed by analysis of gene polymorphisms with real time polymerase chain reaction (TestGen). The distribution of patient’s genotypes and alleles was compared with the control group consisting of residents of the Republic of Tatarstan without carbohydrate metabolism disorders (n=851).

Results: The frequency of alleles and distribution of genotypes of the A/T polymorphism of the FTO gene in the control and study groups corresponded to the Hardy-Weinberg distribution (χ²=1.13, P=0.29 and χ²=0.72, P=0.4, respectively). The distribution of genotypes (AA - 33%, AT - 50%, TT - 17%) and alleles (A - 58%, T - 42%) in individuals with DM2 significantly differed from the control group (AA - 14%, AT - 44.5%, TT - 41.5%, A allele - 36.3%, T allele - 63.8%, OR=2.38, p<0.0001). Significant differences from controls have also been noticed in distribution of genotypes of patients with other disorders of carbohydrate metabolism: with hyperinsulinism (AA - 47.8%, AT - 34.8%, TT - 17.4%, A allele - 65.2%, T allele - 34.8%, OR=3.3, P<0.0001); with impaired glucose tolerance (AA - 55.2%, AT - 34.5%, TT - 10.3%, A allele - 72.4%, T allele - 27.6% OR =4.62, P<0.0001); with impaired fasting glycemia (AA - 30.8%, AT - 53.9%, TT - 15.4%, A allele - 57.7%, T allele - 42.3%, OR=2.38, P=0.04).

Conclusion: The association of the FTO gene with the risk of developing DM2 in Republic of Tatarstan has been proved, which is also confirmed by the results of other studies. The positive correlation of the FTO gene A allele with early carbohydrate metabolism disorders was revealed, which allows to identify groups of increased risk for violations of carbohydrate metabolism. Apparently, the A/T polymorphism of the FTO gene is mostly associated with the secretory function of pancreatic beta cells.

Keywords: FTO, gene, diabetes mellitus type 2, impaired glucose tolerance