Patient-specific genomics and cross-species functional analysis implicate LRP2 in hypoplastic left heart syndrome

Theis, Jeanne L; Vogler, Georg; Missinato, Maria A; Li, Xing; Nielsen, Tanja; Zeng, Xin-Xin I; Martinez-Fernandez, Almudena; Walls, Stanley M; Kervadec, Anaïs; Kezos, James N; Birker, Katja; Evans, Jared M; O'Byrne, Megan M; Fogarty, Zachary C; Terzic, André; Grossfeld, Paul; Ocorr, Karen; Nelson, Timothy J; Olson, Timothy M; Colas, Alexandre R; Bodmer, Rolf

Congenital heart diseases (CHDs), including hypoplastic left heart syndrome (HLHS), are genetically complex and poorly understood. Here, a multidisciplinary platform was established to functionally evaluate novel CHD gene candidates, based on whole-genome and iPSC RNA sequencing of a HLHS family-trio. Filtering for rare variants and altered expression in proband iPSCs prioritized 10 candidates. siRNA/RNAi-mediated knockdown in healthy human iPSC-derived cardiomyocytes (hiPSC-CM) and in developing Drosophila and zebrafish hearts revealed that LDL receptor-related protein LRP2 is required for cardiomyocyte proliferation and differentiation. Consistent with hypoplastic heart defects, compared to patents the proband’s iPSC-CMs exhibited reduced proliferation. Interestingly, rare, predicted-damaging LRP2 variants were enriched in a HLHS cohort; however, understanding their contribution to HLHS requires further investigation. Collectively, we have established a multi-species high-throughput platform to rapidly evaluate candidate genes and their interactions during heart development, which are crucial first steps toward deciphering oligogenic underpinnings of CHDs, including hypoplastic left hearts.