Abstract 11984: A Novel Pathogenic Gata6 Variant Identified in a Family With Persistent Truncus Arteriosus, Childhood-Onset Diabetes Mellitus and Spontaneous Intestinal Perforation

Abstract

GATA6 is a member of the GATA family of transcription factors, among which GATA4, 5 and 6 are known to play critical roles during heart development. Pathogenic variants in GATA6 have been primarily associated with congenital heart disease (CHD) and pancreatic agenesis in humans. Although the phenotypic spectrum associated with pathologic variation in GATA6 has expanded to include developmental delay along with congenital malformations affecting the biliary system and diaphragm, the full disease spectrum of GATA6 pathogenic variation and genotype-phenotype correlations are unclear. Here, we report a family where the father had persistent truncus arteriosus (PTA) and three children had CHD, 2 with PTA and 1 with an atrial septal defect. Notably, the father had childhood-onset diabetes mellitus and one child had spontaneous intestinal perforation (SIP). Using exome sequencing, we identified a novel, heterozygous missense variant in GATA6 (c.1403G>A; p.Cys468Tyr) in affected members. This variant is absent from the gnomAD and ExAC databases and causes a missense change predicted to be damaging by all in silico bioinformatic tools. Sanger sequencing confirmed the exome sequencing results and segregation of this variant. GATA6 p.Cys468Tyr variant affects the highly conserved zinc-finger domain of GATA6 and impedes its ability to bind DNA. Using wild-type and mutant GATA6 constructs driving atrial natriuretic peptide promoter reporter, in vitro luciferase assays showed that p.Cys468Tyr mutant protein exhibited significantly decreased luciferase transcriptional activity. Furthermore, immunofluorescence revealed that p.Cys468Tyr mutant demonstrated an impaired localization pattern in the nucleus and induced protein aggregation. Our findings expand the variant and phenotypic spectrum for GATA6. Our study highlights that GATA6 variants can cause not only cardiac and pancreatic malformations but also gastrointestinal abnormalities, including neonatal SIP. Further investigation is needed to define the mechanisms underlying the full phenotypic spectrum associated with pathogenic variation in GATA6 .