SCN5A and Brugada syndrome: Furthermore, gain-of-function SCN5A mutation encoding NaV1.5 channel abrogates fast channel inactivation, impairs channel closure, and prolongs AP due to INaP [184], eliciting LQT3 syndrome [71,72], while loss-of-function mutation in Brugada syndrome desynchronizes conduction in the ventricles [72,184].