KCNQ1

About KCNQ1

KCNQ1 on chromosome 11p15.5 encodes the pore forming alpha subunit of the slowly activating delayed rectifier potassium channel, which together with the beta subunit KCNE1 carries the IKs current that helps repolarize the heart during phase 3 of the action potential. Loss of function variants cause long QT syndrome type 1, the most common form of congenital long QT syndrome. In type 1, arrhythmic events are classically triggered by exercise, particularly swimming, and by adrenergic stress, and can cause fainting or sudden death. Beta blockers are a mainstay of treatment. Inheriting variants in both copies of KCNQ1 or KCNE1 causes Jervell and Lange Nielsen syndrome, first described in Norway in 1957, which combines congenital deafness, because the channel is needed for potassium secretion into the inner ear fluid, with a severe form of long QT syndrome. Gain of function variants can cause short QT syndrome and familial atrial fibrillation. KCNQ1 lies within an imprinted region, and loss of methylation at the nearby KCNQ1OT1 regulatory region is the most common molecular cause of Beckwith Wiedemann syndrome, an overgrowth disorder. KCNQ1 is also expressed in the stomach, intestine, and pancreas.