In addition to human leukocyte antigen gene encoding B*51 (HLA-B*51) and regions encompassing major histocompatibility complex (MHC) class I, genome-wide association studies (GWAS) have identified several other BD susceptibility genes, including interleukin (IL)10, IL23 receptor (IL23R), IL12 receptor beta 2 (IL12RB2), C-C chemokine receptor 1 gene (CCR1), signal transducer and activator of transcription (STAT4), genes encoding killer cell lectin-like receptor family members (KLRC4-KLRK1), and endoplasmic reticulum aminopeptidase (ERAP1)2, 3, 4, 5, 6. This evidence concerns the gene KLRC4 and Behcet disease.