PTPN1 and Behcet disease: Although accumulating evidence has shown that many genetic factors, such as HLA-B51, IL1A-IL1B, CEBPB-PTPN1, IRF8, ADO-EGR2, RIPK2, and LACC1, are involved in the susceptibility of BD, the exact etiology of BD remains unclear (Takeuchi et al., 2017).