RGS4 and isolated spina bifida: VPA downregulated several genes like insulin-like growth factor 2 receptor (IGF2R), regulator of G-protein signaling 4 (RGS4), alpha 3 (VI) collagen (COL6A3), endothelin receptor type b (EDNRB), Krüppel-like factor 6 (KLF6) and folate receptor 1 (folr1), which are directly associated with neural tube defect (NTD) [5].