Relationship of CARD8 Gene Polymorphisms with Susceptibility to Ankylosing Spondylitis: A Case-Control Study

BACKGROUND The aim of this case-control study was to evaluate the correlation of caspase recruitment domain-containing protein 8 (CARD8) gene rs2043211 (exon) and rs7253718 (intron) polymorphisms with the susceptibility of ankylosing spondylitis (AS) in the Chinese Han population. MATERIAL AND METHODS CARD8 polymorphisms were genotyped by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) in 118 AS patients and 122 healthy persons. Linkage disequilibrium (LD) and haplotype analysis were carried out using Haploview software. Distribution differences of genotypes, alleles and haplotypes between the case and control groups were tested by chi-square test. Relative risk of AS was expressed by odds ratios (ORs) and 95% confidence intervals (CIs). Logistic regression analysis was used to adjust the results of association by clinical parameters. RESULTS For rs2043211, distribution of variant allele T was obviously different between AS patients and healthy controls (P=0.046). It indicated that T allele might increase the susceptibility of AS (OR=1.441, 95%CI=1.006-2.065). Adjusted by clinical characteristics, the significance of difference was slightly decreased (P=0.050, OR=1.439, 95%CI=0.999-2.072). Strong LD existed between rs2043211 and rs7253718 polymorphisms, and rs2043211T-rs7253718G haplotype was significantly associated with increased AS susceptibility (OR=1.787, 95%CI=1.165-2.740). In subgroup analysis, we found that the TT genotype and T allele of rs2043211 significantly increased the risk of AS in males (TT versus AA: OR=2.554, 95%CI=1.079-6.049; T versus A: OR=1.661, 95%CI=1.067-2.586), but not females. CONCLUSIONS CARD8 polymorphisms are likely to be associated with the elevated susceptibility of AS. Present results should be confirmed in the future studies.