Furthermore, the interaction between HLA-B*51 positivity and ERAP1 homozygosity was associated with an odds ratio (OR) for BD of 3.78 (95% CI: 1.94–7.35) versus an OR of 1.48 (95% CI: 0.78–2.80) in HLA-B*51-negative individuals. Here, ERAP1 is linked to Behcet disease.