KCNH2 and Ventricular arrhythmia: Among the monogenic causative factors, mutations in the sodium channel-encoding gene SCN5A, the potassium channel-encoding genes KCNQ1 and KCNH2, and the calcium channel-encoding gene RYR2 cause the majority of ventricular arrhythmias, while some cases are caused by rare variants in other ion channel and structural genes. In addition, the role of somatic mutations has been identified.