For example, BD has been reported to be associated with the interaction between body mass index and variants in the TCF7L2 gene, 20 which is a well-established type 2 diabetes risk gene.21, 22 Similarly, myocardial infarction risk has been reported to be associated with a genetic variant in the ITIH3–ITIH4 genes,23 which has also been implicated in the risk for BD.16 Therefore, it is plausible that other common genetic variants may have pleiotropic effects, contributing to the risk for BD and its common medical comorbidities.24 This evidence concerns the gene ITIH4 and Behcet disease.