Based on the positive association between MTHFR C677T, A1298C and serum homocysteine level [9, 24–26], and the favorable effect of homocysteine level on lipid metabolism [9], we speculate that MTHFR C677T and A1298C polymorphism and high homocysteine level interactively increased the prevalence of dyslipidemia in RSA patients. This evidence concerns the gene MTHFR and metabolic syndrome.