Copy number variants in hypoplastic right heart syndrome.

Hypoplastic right heart syndrome (HRHS) is a rare congenital defect characterized by underdeveloped and malformed structures of the right heart. Familial recurrence of HRHS indicates genetic factors contribute to its etiology. Our study investigates the presence of copy number variants (CNVs) in HRHS cases. We genotyped 42 HRHS cases identified from live births throughout California (2003-2010) using the Illumina HumanOmni2.5-8 array. We identified 14 candidate CNVs in 14 HRHS cases (33%) based on the genes included in the CNVs and their functions. Duplications overlapping part of ERBB4 were identified in two unrelated cases. ERBB4 is a neuregulin receptor with a pivotal role in cardiomyocyte differentiation and heart development. We also described a 7.5 Mb duplication at 16q11-12. Multiple genes in the duplicated region have previously been linked to heart defects and cardiac development, including RPGRIP1L, RBL2, SALL1, and MYLK3. Of the 14 validated CNVs, we identified four CNVs in close proximity to genes linked to the Wnt signaling pathway. This study expands on our previous work supporting the role of genetics in HRHS. We identified CNVs affecting crucial genes and signaling pathways involved in right heart development. ERBB4 and duplication of the 16q11-12 region are important areas for future investigation.