They analyzed cardiac arrhythmia, respiratory control, and epilepsy genes, identifying four pathogenic and two candidate pathogenic variants of cardiac arrhythmia genes: a de novo SCN5A Ile397Val variant, a Gly924Ala and Arg744* nonsense variant in KCNH2, and a Tyr662* nonsense variant in KCNQ1. The variants in KCNQ1 and KCNH2 were previously reported in patients diagnosed with LQTS, and these three variants were absent in more than 60,000 population controls. Here, SCN5A is linked to familial long QT syndrome.