On the genetics of the Silk Route: association analysis of HLA, IL10 , and IL23R-IL12RB2 regions with Behçet’s disease in an Iranian population

Despite that the association of Behcet’s disease (BD) with the HLA-B5 was first established in the 1970s, a number of recent genome-wide association studies have both confirmed and furthered this association—in various populations—to individual SNPs both inside and outside the HLA. The former include HLA-B, MICA, and HLA-A, while the latter encompass IL10 and IL23R-IL12RB2 regions. The present study examined whether some of these SNPs could be replicated in an Iranian population, where the prevalence of disease is amply documented. Eight SNPs were selected and tested in 552 patients and 417 controls. These were rs7539328, rs12119179, rs1495965, rs1518111, and rs1800871 in IL10 and IL23R-IL12RB2 regions and rs114854070, rs12525170, and rs76546355 (formerly rs116799036) in the HLA locus. The well-known BD-associated genes HLA-B and MICA were independently genotyped. Although we were not able to formally replicate the association with IL10 and IL23R-IL12RB2, we do report that BD in Iran is strongly associated with HLA-B*51, MICA-A6, and the three HLA-linked SNPs (odds ratio (OR) = 3.38, P = 6.21 × 10−14; OR = 2.08, P = 1.58 × 10−13; and OR = 1.67–4.05, P = 1.45 × 10−04 to 4.79 × 10−34, respectively). Our data further indicate that the robust HLA-B/MICA association may be explained by a single variant (rs76546355) between the two genes. Overall, these data contribute to a better appraisal of the intriguing linkage between BD and the ancient Silk Route, spanning from the Mediterranean shores to Japan.