MTHFR and Decreased liver function: In this study, we found that MTHFR A1298C (AC, OR: 1.342, 95% CI: 1.070–1.684; CC, OR: 3.709, 95% CI: 1.088–12.637) and MTHFR C677T (TT, OR: 1.587, 95% CI: 0.926–2.720) variants were linked to increased Hcy levels and contributed to the development of VPA-induced liver dysfunction.