Association of rs27044 and rs30187 polymorphisms in endoplasmic reticulum aminopeptidase 1 gene and ankylosing spondylitis susceptibility: A meta-analysis

Background The findings regarding association of endoplasmic reticulum aminopeptidase 1 (ERAP1) gene polymorphisms and ankylosing spondylitis (AS) susceptibility are inconsistent. Our aim is to appraise and merge the existing evidence on the relationship of rs27044 and rs30187 polymorphisms in ERAP1 gene and susceptibility to AS. Methods Electronic databases of PubMed, Web of Science, EMBASE, Cochrane Library, Wanfang, and CNKI were retrieved for relevant publications. The search was conducted from inception to 10 June, 2019. Studies on the association of rs27044 and rs30187 polymorphisms and risk of AS were included. Quality evaluation was carried out using Newcastle-Ottawa Scale (NOS). Summary odds ratios (ORs) and 95% confidence intervals (95% CIs) were calculated to appraise the associations under allelic and genotypic models. Results In total, 26 case-control studies with 31 cohorts containing 17 223 AS patients and 36 915 controls were eligible for this meta-analysis. According to NOS, each study received >= 5 scores. The pooled data indicated that rs27044 and rs30187 polymorphisms were significantly associated with AS susceptibility in the overall population: rs27044, G versus C, OR = 1.24, 95% CI 1.16-1.33, P<.001; rs30187, T versus C, OR = 1.24, 95% CI 1.17-1.33, P<.001. When stratified by ethnicity, rs27044 appeared to be significantly correlated with AS in both Asians and Caucasians. For rs30187, despite positive association being observed under the allelic model in both Asians and Caucasians, the findings of genotypic comparisons supported the association only existed in Caucasians but not Asians. Conclusion This study suggests that rs27044 and rs30187 polymorphisms are significantly associated with increased risk of AS, especially in Caucasians.