Associations between ERAP1 polymorphisms and susceptibility to ankylosing spondylitis: A meta-analysis of East Asian Population

BACKGROUND: The genetic factor is importantly enrolled in the pathogenesis of ankylosing spondylitis (AS) and haplotype leukocyte antigen (HLA)-B27 is the most well-known. However, only 1% to 5% of B27-positive individuals will develop AS, and it confers only 20% to 30% of the overall genetic risks, indicating more genes other than HLA-B27 may play important roles in AS pathologies. The present study aims to investigate whether the polymorphisms of endoplasmic reticulum aminopeptidase 1 (ERAP1) is associated with increased risk of AS susceptibility. METHODS: The Cochrane library, Pubmed, and Embase databases were carefully searched for potential researches published before May 30, 2018. The title, abstract, and full text were assessed to determine whether the paper was suitable for inclusion. The pooled odds ratios (ORs) with 95% confidence intervals (CIs) were presented to assess the associations between ERAP1 polymorphisms and AS susceptibility. RESULTS: The study finally enrolled 10 papers, 4 matched single nucleotide polymorphisms (SNPs) of ERAP1 (rs27044, rs27434, rs30187, and rs27037), and a total of 30552 patients (12492 with AS and 18060 for control). No significant difference was found between the AS susceptibility and polymorphisms of rs27044 and rs27434. However, there was a significant association between ERAP1 polymorphisms rs30187 and rs27037 (T vs C, OR, 1.322, 95% CI = 1.240-10410, P <.05; T vs G, OR, 1.247, 95% CI = 1.149-1.353; P <.05; respectively) and AS susceptibility. CONCLUSION: There was a significant association between ERAP1 polymorphisms (rs30187 and rs27037) and increased risk of AS susceptibility.