The meta-analysis suggested that the T allele of the rs1801133 polymorphism is a risk factor for CAD, which is possibly and partly mediated by abnormal lipid levels.
The univariate analysis indicated that the five variants; rs1800595 (FVR2; factor 5), rs1801133 (MTHFR; 5,10-methylenetetrahydrofolate reductase), rs5918 (HPA-1; human platelet antigen 1), rs1799752 (ACE; angiotensin-converting enzyme), and rs7412 and rs429358 (ApoE; apolipoprotein E) were significantly associated with CAD susceptibility under different genetic models.
Logistic regression analysis after applying factorial design to the studied single nucleotide polymorphisms (SNPs) revealed that homocysteine levels and heterozygous and mutant alleles at rs1801133, rs1805087, along with mutant alleles at rs1801131, rs4646994, conferred higher risk for CAD.
The common MTHFR C677T single nucleotide polymorphism (SNP) (rs1801133) has been associated with raised levels of homocysteine, a well known risk factor for coronary artery disease (CAD).
The adjusted risk of having CAD was more evident for rs1799782 (OR = 1.53; 95% CI: 1.16-2.02; P = 0.003), rs1801133 (OR = 1.54; 95% CI: 1.22-1.94; P < 0.001), and rs4846049 (OR = 1.74; 95% CI: 1.13-2.69; P = 0.013) under the recessive model.
Logistic regression, after adjusting for covariates, demonstrated significant associations of rs1801133 and rs1805087 with CAD in the additive, dominant, and genotype model.
In the presence of low serum folate, mutant 5,20-methylenetetrahydrofolate reductase (MTHFR + [A223V/C677T]) in the homozygous state (+/+), may predispose to higher plasma homocysteine (tHct) levels and coronary artery disease (CAD).