CTLA4 and inflammatory bowel disease: One study carried out on Japanese subjects with IBD found a high frequency of GG genotype at the A+49 G polymorphism in CD patients with fistula compared with those without it (P = 0.0388 ; OR = 2.67).[26] Another study carried out on Chinese patients with UC reported an association between the longer allele (122 bp) of the CTLA-4 gene microsatellite polymorphism (AT)n and UC patients.[25] All other studies carried out on Caucasian British, Spanish, Dutch, Iranian,[27, 37, 39] or Chinese populations[27, 38] did not find any association between CTLA-4 gene polymorphisms and IBD.