KCNK3 and pulmonary arterial hypertension: Using whole-cell patch-clamp electrophysiology in COS-7 cells transfected with KCNK3 WT versus mutated channel harboring one of the six PAH-associated mutations, it was found that all six KCNK3 variants led to loss-of-channel function compared to WT channel, as measured by reduced potassium channel current density.