MTR 2756 A > G polymorphism is associated with the risk of systemic lupus erythematosus in the Polish population.

Systemic lupus erythematosus (SLE) is an autoimmune disease characterized by overexpression of cytokines and T cell accessory molecules, which is due to a reduction of DNA regulatory region methylation in T cells. It has been shown that polymorphic variants of genes encoding key enzymes of folate and methionine metabolism may have an effect on DNA methylation. Therefore, in patients with SLE (n = 106) and controls (n = 141) we examined the distribution of polymorphisms of genes encoding methionine synthase (MTR); 5,10-methylenetetrahydrofolate dehydrogenase, 5,10-methenyltetrahydrofolate cyclohydrolase and 10-formyltetrahydrofolate synthetase (MTHFD1); and methylenetetrahydrofolate reductase (MTHFR). We found that MTR 2756AG (919DG) or GG (919GG) genotype exhibited 2.005-fold increased risk of SLE (95% CI = 1.177-3.416, P = 0.0146). However, MTHFR 677C > T (A222V) and MTHFD1 1958G > A (R653Q) allele and genotype frequencies did not exhibit statistical differences between SLE patients and controls. Since MTR is located on 1q43, our findings confirm the significance of the role of 1q region and the methyl cycle in etiopathogenesis of SLE.