KCNH2 and Sudden unexpected death in epilepsy: For instance, KCNH2 mutations can increase the risk of long QT syndrome (LQT) and epilepsy10 and known or suspected pathological KCNH2 variants are more frequent among decedents with SUDEP.11,12 Since RNA sequencing data reveal that most ion channel genes are expressed in brain and heart, albeit to markedly different degrees (e.g., SCN1A more in brain; SCN5A more in heart), mutations in a single gene can alter excitability in both myocardium (e.g., pacemaker, conduction, myocardium) and brain (e.g., cortex, brainstem).