Molecular Approach of Hereditary Arrhythmias, Long QT Syndrome, and Arrhythmogenic Right Ventricular Cardiomyopathy.

Background: Hereditary cardiac arrhythmias result from mutations in various genes encoding ion channels. One major channelopathy is long QT syndrome, which has excel- lent genetic and clinical heterogeneity. Arrhythmogenic right ventricular cardiomyopa- thy, another hereditary arrhythmia type, also shows high genetic heterogeneity and variable expressivity. Next-generation sequencing is an effective tool to reveal the dis- ease's underlying genetic etiology.

Methods: In this study, we performed clinical exome sequencing or gene panel including cardiac arrhythmia and cardiomyopathy-associated genes by next-generation sequenc-ing in 13 unrelated patients.

Results: Five pathogenic or likely pathogenic mutations, including three novel mutations, were found in the total cases.

Conclusion: This research shows a strong genetic heterogeneity in the disease. In addi- tion, the study revealed that patients with QT interval prolongation on electrocardio- gram might also have mutations in genes that are not associated with long QT syndrome, such as MYLK2 and DSG2. Therefore, our data helped expand the molecular scope of long QT syndrome. It is necessary to study with a broad perspective to elucidate the underly- ing molecular etiology in patients with hereditary cardiac arrhythmias.