Correlations of Methylenetetrahydrofolate Reductase Gene Polymorphism and Genomic DNA Hypomethylation Level with Ankylosing Spondylitis / 中国医学科学院学报

ABSTRACT

To investigate the relationship of both DNA methylation level and methylenetrahydrofolate reductase(MTHFR)gene polymorphism with ankylosing spondylitis(AS). Totally 200 Chinese AS patients with HLA-B27(+)and 120 healthy controls were included from Hunan Province.All the cases were diagnosed according to the 1984 modified New York criteria for AS.The DNA methylation was examined by cytosine extension method,while the MTHFR gene C677T polymorphism was analyzed by the polymerase chain reaction(PCR)and restriction fragment length polymorphism(RFLP).The plasma homocysteine(Hcy)level was examined by enzyme-linked immunosorbent assay(ELISA),while the red blood folate level was analyzed by the specific immunoassays. The ratio of the T/T genotype mutation in the AS group was significantly higher than in the control group(17.0% 5.0%;=9.874, =0.002).The plasma homocysteine concentration of AS group was(18.71 ± 2.42)μmol/L,which was significantly higher than that in normal control group [(10.97 ± 2.93)μmol/L](=24.402, <0.001).The plasma Hcy concentration of the T/T genotype [(21.70±1.80)μmol/L] was significantly higher than that of the C/C genotype[(18.31±1.94)μmol/L](=12.088, =0.01)and the C/T genotype [(17.80±2.18)μmol/L](=6.496, =0.01)in the AS group.The DNA methylation level of the T/T genotype in AS group was significantly lower than that in normal control group(=5.655, <0.001)and also significantly lower than those of the C/C genotype(=11.514, <0.001)and the C/T genotype in AS group(=10.287, <0.001). In the Han population in Hunan Province,the C677T polymorphism of the MTHFR gene is associated with the onset of AS.The T/T mutation at position 677 of the MTHFR gene is an important influencing factor for hyperhcyemia in the AS patients.The T/T mutation at position 677 of the MTHFR gene is associated with genomic DNA hypomethylation.Thus,hypomethylation of DNA may be one of the pathogenic mechanisms of AS.