Association of receptor activator of nuclear factor-kappaB ligand (RANKL) gene polymorphisms with the susceptibility to ankylosing spondylitis: a case-control study

To investigate the association between receptor activator of nuclear factor-kappaB ligand (RANKL) gene polymorphisms and the susceptibility to ankylosing spondylitis (AS) in a Chinese Han population. Three hundred and fifty-two AS patients and 299 age- and gender-matched controls were recruited in this study. Peripheral blood samples were collected from all the subjects and the genomic DNA was then extracted. Three single nucleotide polymorphisms (SNPs) of the RANKL gene (rs2277438, rs7984870 and rs9533156) were genotyped using the TaqMan assay. The frequencies of alleles and genotypes were compared between AS patients and normal controls. The distributions of genotype frequencies in rs2277438 were significantly different between AS patients and normal controls (P < 0.05). The frequency of G allele of SNP rs2277438 in AS patients was significantly higher than that in normal controls (P < 0.05). The frequencies of genotypes with G allele (GG and AG) were significantly higher in AS patients when compared with normal controls (OR = 1.573, 95 % CI 1.151-2.150, P < 0.05). Neither the genotype frequencies nor the allele frequencies of rs7984870 and rs9533156 were found to be significantly different between AS patients and normal controls (P > 0.05). The current study demonstrated that SNP rs2277438 of the RANKL gene was associated with the susceptibility of AS in a Chinese Han population. Genotypes with G allele (GG and AG) were identified as the risk factors for the occurrence of AS.