ERAP1 GENE POLYMORPHISMS INFLUENCE THE CLINICAL CHARACTERISTICS OF ANKYLOSING SPONDYLITIS

Objective. Our aim was to investigate whether two ERAP1 gene variants, rs30187 and rs27044, influence the clinical characteristics of ankylosing spondylitis (AS) (the age of onset and the type of articular manifestations - axial or mixed) in Romanian patients. Methods. We studied 94 AS patients and 139 healthy controls. The method used for genotyping the two non-synonymous single nucleotide polymorphisms (SNPs) was real-time polymerase chain reaction. Association tests were carried out using PLINK 1.07 software. We analyzed separately the subgroups of AS patients with early onset (age 30 years), as well as the subgroups of patients with axial manifestations and mixed manifestations (axial and peripheral). Results. Significant association between ERAP1 polymorphisms and AS is only present for patients who experienced an early onset (p = 0.04 for rs30187 and p = 0.007 for rs27044) and not for those with late onset (p = 0.32 for rs30187 and p = 0.29 for rs27044). Polymorphism rs30187 is associated only with the axial form of AS (p = 0.02), while rs27044 is associated only with the mixed form of the disease (p = 0.02). Conclusions. Our findings demonstrate a consistent association between the studied ERAP1 gene SNPs and certain phenotypic characteristics of AS, suggesting that these gene variants may influence the AS onset and the presence of axial or mixed manifestations of AS.