Association between the FTO polymorphic variants and obesity in the Belarusian population

Abstract

Overweight and obesity refer to the abnormal and excessive deposition of adipose tissue in the human body causing significant harm to health. Unfortunately, there has always been a persisting upward trend in the number of overweight people. The development of obesity may be caused by a combination of excessive food intake, low physical activity, and a hereditary predisposition to it. Studies of the genotypes of obese individuals allowed identifying a number of polymorphic variants of genes that contribute to a genetic predisposition to an excessive weight gain. One of the most significant predictors of obesity is the FTO gene (a fat mass and obesity-associated gene). Genotyping of 655 representatives of the Republic of Belarus was carried out for 13 polymorphic variants of the FTO gene. Genomic DNA extraction was carried out from the peripheral venous blood samples. Real-time PCR was performed for the evaluation of polymorphic variants of the FTO gene. A significant association of the genotype with the body mass index was observed in eight polymorphic variants of the FTO gene: In the carriers of minor homozygotes of polymorphic variants rs11075990, rs1121980, rs1421085, rs17817449, rs3751812, rs9939609, rs9940128, and rs9941349, the body mass index (BMI) was much higher compared with the carriers of corresponding major homozygotes P = 0.0022 – 0.021. An analysis of the linkage disequilibrium of 13 polymorphic variants of the FTO gene was carried out. It was found that eight polymorphic variants of the FTO gene for which a statistically significant association with BMI was shown constitute one block of linkage disequilibrium (r2 = 0.82 – 1.0, P < 0.001) and form two most common haplotypes: A/G/T/T/G/T/G/C (51.9%) and G/A/C/G/T/A/A/T (42.8%). Therefore, to determine the risk for obesity development, it is sufficient to conduct genetic testing for one of these polymorphic variants. This greatly facilitates the process of determining a genetic predisposition to excess weight.