KCND3 and amelogenesis imperfecta type 1G: KCND3 V392I mutation was reported in an 18-year-old young man with ERS. Acacetin, a potent Ito current blocker, was studied as a novel therapeutic agent for KCND3-induced ERS. Acacetin significantly inhibited 93.2% of KCND3 V392I peak Ito current.