Within the HLA (chromosome 6p21) there was very strong evidence for association between rs2523589 (2.4 kb 5′ of HLA-B) and the odds of developing mouth ulcers (OR 0.94 per G allele, 95% CI: 0.93, 0.94; EAF 0.50; P = 1.6e−54). The gene discussed is HLA-B; the disease is Oral ulcer.