Kårhus et al. screened 2293 subjects for HLA-DQ2 and DQ8 and found that the prevalence of IBS in patients without HLA-DQ2 or DQ8 genes was 4.6% (55/1197), while the prevalence of IBS in patients with HLA-DQ2 or DQ8 was only 2.6% (28/1086). This evidence concerns the gene TOR1A and irritable bowel syndrome.