Interleukin‐21 receptor gene polymorphism (rs2285452 A/G) is associated with susceptibility to Behçet's disease

Abstract Behçet's disease (BD) is a chronic auto inflammatory disorder of unknown aetiology. Recently, the dysregulation of interleukin‐21 receptor (IL‐21R) has been incriminated in different autoimmune and auto‐inflammatory diseases, such as systemic lupus erythematous, rheumatoid arthritis, and type 1 diabetes. Herein, we aimed to investigate the association of two Il‐21R gene polymorphisms with BD. IL‐21R rs2214537 and IL‐21R rs2285452 genotypings were investigated in a cohort of 110 adult patients with BD and 116 age and gender unmatched healthy controls. Genotyping was performed by mutagenically separated polymerase chain reaction with newly designed primers. IL‐21R rs2285452 genotypes and alleles distribution were statistically different between patients with BD and controls. GA and AA genotypes carrying the minor A allele were more frequent in patients with BD than in healthy controls (37.3% and 11.8% vs. 23.3% and 3.4%, respectively). The minor A allele was associated with an increased BD risk (odds ratios = 2.42, 95% confidence interval = 1.214.87, p = .005). IL‐21R rs2214537 GG genotype was found to be associated with susceptibility to BD in the recessive model (GG vs. CC + CG; p = .046, OR = 1.91, 95% CI = 1.003.650. IL‐21R rs2285452 and IL‐21R rs2214537 were not in linkage disequilibrium ( D ' = 0.42). The AG haplotype was more frequently observed in patients with BD than in controls (0.247 vs. 0.056, p = .0001). This study for the first time reports the association of IL‐21R rs2285452 and IL‐21R rs2214537 with BD. Functional studies are required to elucidate the exact role of these genetic variants.