As shown in Figure 4, no substantial heterogeneity was found (χ2 = 4.99, Pheterogeneity = 0.173, I2 (%)  = 39.8) and there was no statistical evidence of an association between MTR A2756G polymorphism and the CHD risk (OR = 1.05, 95% CI = 0.66–1.66, P = 0.837). Here, MTR is linked to coronary artery disorder.