Association between MTHFR polymorphisms and ankylosing spondylitis risk

Purpose: This study was aimed to detect the association between methylenetetrahydrofolate reductase (MTHFR) gene polymorphisms (C677T and A1298C) and ankylosing spondylitis (AS) risk. Methods: With matched age and gender, 113 AS patients and 120 healthy controls were recruited in this case-control study. Polymerase chain reaction-restriction fragment length polymorphisms (PCR-RFLP) were adopted to test the C677T and A1298C polymorphisms of MTHFR gene. Analyses of linkage disequilibrium and haolotypes of these polymorphisms were conducted by Haploview software. Differences in frequencies of genotypes, alleles and haplotypes in case and control groups were analyzed by chi-square test. Besides, the relative risk of AS was represented by odds ratios (ORs) with 95% confidence intervals (95% CIs). Results: Genotypes TT and CC of C677T and A1298C polymorphisms were obviously related to the occurrence of AS (P=0.039, OR=2.103, 95% CI=1.033-4.281; P=0.030, OR=3.456, 95% CI=1.070-11.161). Meanwhile, 677T was a susceptible allele for AS (P=0.039, OR=1.473, 95% CI=1.020-2.127). But no significant association existed between A1298C alleles and AS risk. Linkage disequilibrium and haplotype analysis indicated that T-A haplotype was more often discovered in cases, which suggested that haplotype T-C may be a risk factor for AS occurrence (P=0.008, OR=1.772, 95% CI=1.156-2.715). Conclusion: C677T and A1298C polymorphisms in MTHFR gene may increase the risk of AS.