NOS1AP and familial long QT syndrome: Although the functional role of NOS1AP in cardiac repolarization is not established, QTi-associated common variants at the NOS1AP locus are also associated with an increased risk of SCD in the general population (Eijgelsheim et al. 2009; Kao et al. 2009) and are genetic modifiers of cardiac outcomes in subjects with LQTS (Schwartz et al. 2018).