**Abstract**

Inflammatory bowel disease (IBD) mainly includes ulcerative colitis (UC) and Crohn's disease (CD). Both conditions are characterized by chronic inflammation of the gastrointestinal tract, with alternating periods of relapse and remission. Both forms of IBD involve an uncontrolled inflammatory process in the intestines, leading to worsening quality of life and requiring long-term medical and/or surgical intervention. Epidemiological and clinical studies suggest that the pathogenesis of inflammatory bowel disease is strongly linked to genetic predisposition. CD and UC are considered polygenic diseases in which familial clustering is observed in 5–10% of patients. Among genetic factors associated with IBD development, it has been found that many single nucleotide polymorphisms are associated with susceptibility to IBD progression. SNP can affect the production or function of a protein and thus affect the development of the disease. However, although the overall role of genes involved in the development of IBD is already in most cases known, as of today it is unclear how the SNPs in these genes affect cellular function, or how such changed cellular functions would contribute to the development of IBD. In the present work several selected polymorphisms in genes involved in IBD development are discussed.

**Keywords:** ulcerative colitis, Crohn's disease, single-nucleotide polymorphisms
