Mutations in genes related to myocyte contraction and ventricular septum development in non-syndromic tetralogy of Fallot

Drayton C Harvey; Riya Verma; Brandon Sedaghat; Brooke E Hjelm; Sarah U Morton; Jon G Seidman; S Ram Kumar

doi:10.3389/fcvm.2023.1249605

Mutations in genes related to myocyte contraction and ventricular septum development in non-syndromic tetralogy of Fallot

Front Cardiovasc Med. 2023 Sep 28:10:1249605. doi: 10.3389/fcvm.2023.1249605. eCollection 2023.

Authors

Drayton C Harvey^{1

2}, Riya Verma^{1

3}, Brandon Sedaghat⁴, Brooke E Hjelm⁵, Sarah U Morton⁶, Jon G Seidman⁷, S Ram Kumar^{1

8

9}

Affiliations

¹ Departments of Surgery, Keck School of Medicine, University of Southern California, Los Angeles, CA, United States.
² Pathology, Keck School of Medicine, University of Southern California, Los Angeles, CA, United States.
³ Stem Cell Biology and Regenerative Medicine, Keck School of Medicine, University of Southern California, Los Angeles, CA, United States.
⁴ Department of Medicine, Rosalind Franklin University School of Medicine and Science, Chicago, IL, United States.
⁵ Translational Genomics, Keck School of Medicine, University of Southern California, Los Angeles, CA, United States.
⁶ Department of Pediatrics, Boston Children's Hospital, Boston, MA, United States.
⁷ Department of Genetics, Harvard Medical School, Boston, MA, United States.
⁸ Pediatrics, Keck School of Medicine, University of Southern California, Los Angeles, CA, United States.
⁹ Department of Surgery, University of Nebraska Medical Center, Omaha, NE, United States.

Abstract

Objective: Eighty percent of patients with a diagnosis of tetralogy of Fallot (TOF) do not have a known genetic etiology or syndrome. We sought to identify key molecular pathways and biological processes that are enriched in non-syndromic TOF, the most common form of cyanotic congenital heart disease, rather than single driver genes to elucidate the pathogenesis of this disease.

Methods: We undertook exome sequencing of 362 probands with non-syndromic TOF and their parents within the Pediatric Cardiac Genomics Consortium (PCGC). We identified rare (minor allele frequency <1 × 10^-4), de novo variants to ascertain pathways and processes affected in this population to better understand TOF pathogenesis. Pathways and biological processes enriched in the PCGC TOF cohort were compared to 317 controls without heart defects (and their parents) from the Simons Foundation Autism Research Initiative (SFARI).

Results: A total of 120 variants in 117 genes were identified as most likely to be deleterious, with CHD7, CLUH, UNC13C, and WASHC5 identified in two probands each. Gene ontology analyses of these variants using multiple bioinformatic tools demonstrated significant enrichment in processes including cell cycle progression, chromatin remodeling, myocyte contraction and calcium transport, and development of the ventricular septum and ventricle. There was also a significant enrichment of target genes of SOX9, which is critical in second heart field development and whose loss results in membranous ventricular septal defects related to disruption of the proximal outlet septum. None of these processes was significantly enriched in the SFARI control cohort.

Conclusion: Innate molecular defects in cardiac progenitor cells and genes related to their viability and contractile function appear central to non-syndromic TOF pathogenesis. Future research utilizing our results is likely to have significant implications in stratification of TOF patients and delivery of personalized clinical care.

Keywords: congenital heart defect; conotruncal defects; de novo variants; exome sequencing; tetralogy of fallot.

Abstract

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