However, studies concerning the interactions of SNPs in folate-related genes and maternal tobacco exposure were lack, Hobbs [42] indicated that the combined effect of elevations in maternal homocysteine, smoking, and the MTHFR CC genotype increased the risk of having a CHD-affected pregnancy (aOR = 11.8), compared with women who did not smoke, did not have an elevated homocysteine, and had the MTHFR 677 CC genotype served as the reference group. This evidence concerns the gene MTHFR and coronary artery disorder.