Comparison of IL-23 receptor gene polymorphisms in patients with primary sjogren syndrome, ankylosing spondylitis. and ankylosing spondylitis with sjogren's syndrome

Objectives: The frequency of Interleukin-23 receptor (IL-23R) gene polymorphism was previously studied in Ankylosing spondylitis (AS) and Sjogren syndrome (SS). However, it hasn't been studied in patients AS with SS. Methods: The study included 124 patients with AS, 55 patients with SS and 12 patients with association of AS and SS. Results: It was found that there was an increase in the frequency of rs10889677 gene mutant genotype while a decrease in the frequency of in rs11209032 gene mutant genotype in AS group compared to the healthy controls. In SS group, it was found that there was an increase the frequencies of rs11805303 gene wild genotype and rs2201841 gene wild genotype while a decrease in the frequencies of rs11209032 gene heterozygote genotype and rs10489629 gene mutant genotype when compared to healthy controls. CGCAA haplotype was associated with risk for AS (P=0.0125; RR: 1.32). CGCAG haplotype was associated with protective effect against ankylosing spondylitis (P=0.0042; RR: 0.52). While CTCAA haplotype was found to be protective against SS (P=0.022; RR: 0.46), it was associated with increased risk for association of AS and SS (P=0.0095; RR: 2.79). CTCAG haplotype was associated with protective effect against association of AS and SS (P=0.0151; RR: 0.02). It was observed that TGCGG haplotype increased significantly in SS group compared to the healthy controls and that it was related with increased risk for SS (P=0.032, RR: 2.56). Conclusion: Genotype distribution and genetic diversity vary among ethnic groups. Studies with larger sample size are needed to further clarify this issue.