High HLA-B*51 frequency observed in Silk Road populations let to arguments for past pathogen or some other environment factor driven selection favoring HLA-B*51 in these populations, therefore, increased BD risk in contemporary populations is suggested to be a result of past selection on HLA-B alleles (Piga and Mathieu, 2014; Sazzini et al., 2015; Smith et al., 2021). The gene discussed is HLA-B; the disease is Behcet disease.