Figure 5.

KCNT1‐L437F channels are blocked by quinidine but not by other conventional anticonvulsants. (A) Automated patch‐clamp recording of KCNT1‐L437F expressing cells demonstrated a dose‐response to quinidine with an IC₅₀ unchanged from WT CHO cells. (B) Screening of conventional anticonvulsants at maximum therapeutic serum concentrations including ethosuximide (ESM), valproic acid (VPA), lacosamide (LCM), lamotrigine (LTG), phenytoin (PHT) compared to a traditional potassium channel blocker (4‐AP) and quinidine displays a lack of channel block, consistent with prior reports of seizures in KCNT1‐associated epilepsy refractory to conventional anticonvulsants.