SORBS2is a susceptibility gene to arrhythmogenic right ventricular cardiomyopathy

ABSTRACT BACKGROUND Arrhythogenic right ventricular cardiomyopathy (ARVC) is an inherited cardiomyopathy characterized by right ventricular remodeling and ventricular arrhythmia. To date, 16 ARVC causative genes have been identified from human genetic studies, accounting for about 60% of ARVC probands. Genetic basis for the remaining 40% ARVC probands remain elusive. METHODS Prompted by a zebrafish mutagenesis screen that suggested the Sorbin and SH3 domain-containing 2 (SORBS2) ortholog as a candidate cardiomyopathy gene, we conducted detailed expressionl analysis of Sorbs2 in mice, as well as phenotypic characterization in the Sorbs2 knock-out (KO) mice. The intercalated disc (ICD) expression pattern and ARVC-like phenotypes further prompted us to conduct targeted sequencing of human patients with ARVC to search for rare variants in the SORBS2 gene. RESULTS Sorbs2 is robustly expressed in the mouse heart, encoding an adhesion junction/desmosome protein that is mainly localized to the ICD. A mutation with near complete depletion of the Sorbs2 protein in mouse results in phenotypes characteristic of human ARVC, such as dilated right ventricle (RV), RV dysfunction, spontaneous ventricular tachycardia (VT), and premature death. Sorbs2 is required to maintain the structural integrity of ICD. Its absence resulted in profound cardiac electrical remodeling with impaired impulse conduction and action potential derangements. Five rare variants were identified from a cohort of 59 ARVC patients, among which two variants affect splicing. CONCLUSIONS Sorbs2 KO mouse is an ARVC model and SORBS2 is a new ARVC susceptibility gene.