Rare and de novo variants in 827 congenital diaphragmatic hernia probands implicate LONP1 and ALYREF as new candidate risk genes

Abstract

Congenital diaphragmatic hernia (CDH) is a severe congenital anomaly that is often accompanied by other anomalies. Although the role of genetics in the pathogenesis of CDH has been established, only a small number of disease genes have been identified. To further investigate the genetics of CDH, we analyzed de novo coding variants in 827 proband-parent trios and confirmed an overall significant enrichment of damaging de novo variants, especially in constrained genes. We identified LONP1 (Lon Peptidase 1, Mitochondrial) and ALYREF (Aly/REF Export Factor) as novel candidate CDH genes based on de novo variants at a false discovery rate below 0.05. We also performed ultra-rare variant association analyses in 748 cases and 11,220 ancestry-matched population controls and identified LONP1 as a risk gene contributing to CDH through both de novo and ultra-rare inherited largely heterozygous variants clustered in the core of the domains and segregating with CDH in familial cases. Approximately 3% of our CDH cohort was heterozygous with ultra-rare predicted damaging variants in LONP1 who have a range of clinical phenotypes including other anomalies in some individuals and higher mortality and requirement for extracorporeal membrane oxygenation. Mice with lung epithelium specific deletion of Lonp1 die immediately after birth and have reduced lung growth and branching that may at least partially explain the high mortality in humans. Our findings of both de novo and inherited rare variants in the same gene may have implications in the design and analysis for other genetic studies of congenital anomalies.