Associations between ERAP1 polymorphisms and ankylosing spondylitis susceptibility in HLA-B27 positive population: a Meta-analysis and bioinformatics analysis.

Human leukocyte antigen (HLA)-B27 confers a key role in ankylosing spondylitis (AS) susceptibility. Endoplasmic reticulum aminopeptidase 1 (ERAP1) polymorphisms are associated with AS susceptibility in common population. In this study we intended to evaluate the possible association between ERAP1 polymorphisms and AS susceptibility in HLA-27 positive population. Data were collected from Pubmed, Embase, and Cochrane databases. The pooled odds ratios and 95% confidence intervals of the minor allele of each locus were calculated to appraise the associations under ERAP1 polymorphisms and AS in HLA-B27 positive population. Bioinformatics analysis was performed to explore the underlying mechanism. Four studies were included in this meta-analysis. There was a significant association between the minor allele of rs2287987 and reducing the risk of developing AS in HLA-B27 positive population. But there was no significant association between the minor allele of rs30187, rs27044, rs10050860 and rs17482078 and AS susceptibility. According to HaploReg, 5 motifs changed for rs2287987 were found. The eQTL analysis demonstrated that rs2287987 may influence ERAP1 expression. Rs2287987 in ERAP1 may have small influence on AS susceptibility in HLA-B27 positive population. Bioinformatics analysis indicated that the altered motifs and the change of EARP1 expression may influence the AS susceptibility.