Associations between ERAP1 polymorphisms and ankylosing spondylitis susceptibility: a meta-analysis

Objective The aim of this study was to determine whether five polymorphisms of endoplasmic reticulum aminopeptidase 1 (ERAP1) confer susceptibility to ankylosing spondylitis (AS). Methods The authors conducted five types of meta-analysis on the associations between the rs27044, rs17482078, rs10050860, rs30187, and rs2287987 polymorphisms of ERAP1 and AS susceptibility, using fixed and random effects models. Results Six studies were included in this meta-analysis, which in total involved 4,594 AS patients and 3,971 controls, five European populations, and one Asian population. Meta-analysis identified a significant association between AS and the two alleles of the rs27044 polymorphism in all study subjects [odds ratio (OR) = 1.333, 95% confidence interval (CI) = 1.102-1.612, p = 0.003]. Stratification by ethnicity identified a significant association between this polymorphism and AS in Europeans (OR = 1.281, 95% CI = 1.032-1.588, p = 0.024) and in Asians (OR = 1.554, 95% CI = 1.313-1.838, p = 2 x 10(-8)), and meta-analysis of the rs30187 polymorphism showed the same pattern. Furthermore, analysis revealed significant associations between the two alleles of the rs17482078, rs10050860, and rs2287987 polymorphisms and the risk of developing AS in Europeans (OR = 0.726, 95% CI = 0.655-0.805, p < 1 x 10(-10); OR = 0.724, 95% CI = 0.665-0.787, p < 1 x 10(-10); OR = 0.708, 95% CI = 0.639-0.784, p < 1 x 10(-10), respectively). However, the single Asian study included showed no association between the rs17482078, rs30187, and rs2287987 polymorphisms and AS. Conclusions This meta-analysis shows that the rs27044, rs17482078, rs10050860, rs30187, and rs2287987 polymorphisms of ERAP1 are associated with the development of AS in Europeans. However, further study of this association is required in other ethnic groups.