Abstract. Aim of the study: to determine the prevalence of FTO gene polymorphism and clinical importance of it in patients with non-alcoholic fatty liver disease (NAFLD) associated with obesity.
Material and methods. 114 patients with NAFLD associated with obesity or overweight were examined. The comparison group consisted of 72 healthy individuals with a BMI <25, comparable to the patients by gender and age. Oligonucleotide polymorphism T / A of the FTO gene (rs9939609) was determined using allele-specific PCR (OOO NPF Litekh) followed by electrophoretic detection.
Results. In patients with NAFLD associated with overweight and obesity, the FTO (rs9939609) T / A polymorphism was more often than in the healthy population. The AA genotype and the A allele in obesity of the 2 and 3 classes are more often, and the TT genotype is less often than in persons with class 1 obesity and overweight. Unfavorable genotypes of the FTO gene TA and AA were associated with high blood triglycerides. In patients with NAFLD with type 2 diabetes, allele A is more often observed and, less often, the TT genotype. The development of non-alcoholic steatohepatitis often occurs in the presence of the A allele of the FTO gene.
Conclusion. The studies carried out indicate the important role of the FTO (rs9939609) T/A gene polymorphism in the pathogenesis of obesity and non-alcoholic fatty liver disease.

Keywords: obesity, non-alcoholic fatty liver disease, FTO gene polymorphism