KCNH2 and Prolonged QT interval: The standard four-gene molecular autopsy, encompassing analysis of KCNQ1, KCNH2, SCN5A (associated with long QT syndrome), and RYR2 (linked to catecholaminergic polymorphic ventricular tachycardia), has been expanded to include calmodulin-encoding genes (CALM1, CALM2, CALM3) due to their association with severe, early-onset long QT syndrome (21).