A 25-year-old man presents to rheumatologist with complaints of joint pain involving large joints of legs which exacerbates frequently accompanied by diarrhea. Which of the following gastrointestinal diseases is most likely to be implicated as the cause of the patient's joint problems?

- Most frequent GIT disorder associated with sacroiliitis (related to HLA-B27) or lower limb ahritis is chronic inflammatory bowel diseases like ulcerative colitis & Crohn's disease. - Other GI diseases associated with ahropathy are Whipple's disease, Behcet's syndrome, and celiac disease.