Background. Peptic ulcer disease occurs in 5–10% of the adult population and is characterized by a high percentage of complications, which represents a serious medical and social problem. According to modern medical reviews, despite the undoubted commonality of pathogenetic mechanisms, deviation in the implementation of duodenal ulcer (DU) or erosive gastroduodenitis (EGD) is largely dictated by genetically predetermined characteristics of the response to etiological factors by the wall of the stomach and duodenum. In this regard, it seems relevant to study the role of immune response factors in the focus of associations of polymorphic variants of certain groups of candidate genes in the development of erosive and ulcerative lesions of the upper gastrointestinal tract in children.
Objective. Evaluation of the influence of intergenic relationships of polymorphisms of candidate genes C (+3953) T and C (-511) T of the IL-1β gene and VNTR polymorphism of the IL-1RN gene in the development of erosive gastroduodenitis and peptic ulcer in children.
Methods. The sample consisted of 100 patients (main group) with established diagnoses of DU and chronic EGD and 100 people in the control group. Genotyping was carried out using the polymerase chain reaction method.
Results. The three-factor interaction between genotypes TT (+3953C/T), CT (C+511T) IL-1β and 1/1 (rs223466 IL-1RN gene) predisposed to the development of diseases in children of the main group, while the combination of CC+ genotypes TT+1/2 was associated with a reduced risk of developing DU and EGD in children. The CT+TT haplotype (C (-511) T, C (+3953) T polymorphisms of the IL-1β gene) was predisposing, and the three-factor model CC+CC+1/1 was protective in relation to the development of DU in children.
Conclusion. These polymorphic variants have regulatory potential in the implementation of DU in children.

Keywords: polymorphisms, interleukin-1β, peptic ulcer, genes