From January 2020 to December 2024, diagnosed ulcerative colitis(UC) patients and gender- and age-matched normal controls were enrolled from the Department of Gastroenterology, the Second Affiliated Hospital of Wenzhou Medical University. Investigators' aim is to investigate the associations of IL-7R gene polymorphisms with the risk and clinicopathological characteristics of UC, and to analyze the effects of IL-7R gene variations on the clinical response of vedolizumab(VDZ) treatment in UC patients.