MTHFR and Decreased liver function: As shown in Table 6, the MTHFR A1298C polymorphism (r = 1.646, p = 0.001), MTHFR C677T polymorphism (r = 1.162, p = 0.007) and Hcy level (r = 1.334, p = 0.030) exhibited a significant positive correlation with VPA-associated liver dysfunction.