Susceptibility to ankylosing spondylitis: evidence for the role of ERAP1, TGFb1 and TLR9 gene polymorphisms

Genetic factors are thought to be crucial in the pathogenesis of ankylosing spondylitis (AS). Recent studies have reported that ERAP1, TGB beta 1 and TLRs genes are likely to have association with AS in different populations. We carried out this study to determine whether single-nucleotide polymorphisms covering the three genes are associated with AS in a Chinese Han population. Genomic DNA was isolated from the peripheral blood of 328 patients with AS and 627 healthy blood donors from Jinan region as a case-control study. The diagnosis of AS was made according to the modified New York criteria. The ERAP1 rs27044, TGB beta 1 rs1800470 and TLR9 rs55704465 were genotyped by a polymerase chain reaction--restriction fragment length polymorphism method. Strong association with AS was observed for marker rs27044, but no significant differences were observed between AS patients and controls in the frequencies of the carriership of the alleles rs55704465 and rs1800470. Our data thus indicate that ERAP1 likely constitutes one of AS-associated loci of susceptibility after HLA in Chinese Han population. On the contrary, TGFB1 and TLR9 variations show no association with the susceptibility of AS.