Abstract 17517: Genetics of Left Ventricular Noncompaction Cardiomyopathy

Left ventricular noncompaction cardiomyopathy (LVNC) is an increasingly recognized cause of heart failure, arrhythmias, thrombembolic events, and sudden cardiac death. To better understand the contribution of genetic factors to this disease, allowing a better diagnosis, counseling of affected families and estimation of prognosis, we have performed whole-exome deep-sequencing on a cohort of in 104 subjects (67 unrelated LVNC probands, 26 affected relatives form 15 families and 11 additional healthy relatives). By annotating the detected variants with mutation databases (HGMD), we were able to for the first time show an overlap between the distinct causes of LVNC and other genetic cardiomyopathies, as 8 mutations were previously reported to cause hypertrophic cardiomyopathy (HCM), 9 dilated cardiomyopathy (DCM) and 6 arrhythmogenic right ventricular cardiomyopathy (ARVC). Besides already known genetic causes, we identified a number of genes contributing to different pathways, so far not discussed to be of relevance for LVNC. From those, TTN truncating mutations were very frequent, affecting 17.9% of all index patients and one fifth of the familial cases. For two genes, which have already been linked to cardiac noncompaction in animal models, we are first to describe a relevant number of patients carrying mutations in these genes NCOR2 (frequency = 7.5%) and XIRP2 (4.5%). By performing segregation and linkage analyses, as well as in vivo studies, we provide for the first time evidence for a gene that was previously not known to cause a human disease, Compactin1. In conclusion, we show that LVNC has a substantial genetic component and suggest new candidate genes for a functional dissection of their contribution to cardiac development and as potential therapeutic target.