The subgroup analysis by geographical regions revealed that the significant association between the maternal MTHFR C677T polymorphism and DS existed in Asian population (for T vs. C: OR = 1.51; 95% CI = 1.09−2.10; p = 0.01; I2 = 69.43%; Pheterogeneity = 0.0003; PPb = 0.82) (Figure 5; Table 3). The gene discussed is MTHFR; the disease is Dravet syndrome.