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TFAP2B Haploinsufficiency Impacts Gastrointestinal Function and Leads to Pediatric Intestinal Pseudo-obstruction

Authors :
Almira Zada
Laura E. Kuil
Bianca M. de Graaf
Naomi Kakiailatu
Jonathan D. Windster
Alice S. Brooks
Marjon van Slegtenhorst
Barbara de Koning
René M. H. Wijnen
Veerle Melotte
Robert M. W. Hofstra
Erwin Brosens
Maria M. Alves
Source :
Frontiers in Cell and Developmental Biology, Vol 10 (2022)
Publication Year :
2022
Publisher :
Frontiers Media S.A., 2022.

Abstract

Background: Pediatric Intestinal Pseudo-obstruction (PIPO) is a congenital enteric disorder characterized by severe gastrointestinal (GI) dysmotility, without mechanical obstruction. Although several genes have been described to cause this disease, most patients do not receive a genetic diagnosis. Here, we aim to identify the genetic cause of PIPO in a patient diagnosed with severe intestinal dysmotility shortly after birth.Methods: Whole exome sequencing (WES) was performed in the patient and unaffected parents, in a diagnostic setting. After identification of the potential disease-causing variant, its functional consequences were determined in vitro and in vivo. For this, expression constructs with and without the causing variant, were overexpressed in HEK293 cells. To investigate the role of the candidate gene in GI development and function, a zebrafish model was generated where its expression was disrupted using CRISPR/Cas9 editing.Results: WES analysis identified a de novo heterozygous deletion in TFAP2B (NM_003221.4:c.602-5_606delTCTAGTTCCA), classified as a variant of unknown significance. In vitro studies showed that this deletion affects RNA splicing and results in loss of exon 4, leading to the appearance of a premature stop codon and absence of TFAP2B protein. Disruption of tfap2b in zebrafish led to decreased enteric neuronal numbers and delayed transit time. However, no defects in neuronal differentiation were detected. tfap2b crispants also showed decreased levels of ednrbb mRNA, a downstream target of tfap2b.Conclusion: We showed that TFAP2B haploinsufficiency leads to reduced neuronal numbers and GI dysmotility, suggesting for the first time, that this gene is involved in PIPO pathogenesis.

Details

Language :
English
ISSN :
2296634X
Volume :
10
Database :
Directory of Open Access Journals
Journal :
Frontiers in Cell and Developmental Biology
Publication Type :
Academic Journal
Accession number :
edsdoj.88f91001bc774e99be4b2759acc6def2
Document Type :
article
Full Text :
https://doi.org/10.3389/fcell.2022.901824