2. Academic Validation
  3. Neonatal-Onset Chronic Diarrhea Caused by Homozygous Nonsense WNT2B Mutations

Neonatal-Onset Chronic Diarrhea Caused by Homozygous Nonsense WNT2B Mutations

  • Am J Hum Genet. 2018 Jul 5;103(1):131-137. doi: 10.1016/j.ajhg.2018.05.007.
Amy E O'Connell 1,  Fanny Zhou 2,  Manasvi S Shah 2,  Quinn Murphy 3,  Hannah Rickner 2,  Judith Kelsen 4,  John Boyle 5,  Jefferson J Doyle 6,  Bharti Gangwani 6,  Jay R Thiagarajah 7,  Daniel S Kamin 7,  Jeffrey D Goldsmith 8,  Camilla Richmond 7,  David T Breault 9,  Pankaj B Agrawal 10
Affiliations

Affiliations

  • 1 Division of Newborn Medicine, Boston Children's Hospital, Boston, MA 02115, USA; Department of Pediatrics, Harvard Medical School, Boston, MA 02115, USA. Electronic address: amy.oconnell@childrens.harvard.edu.
  • 2 Division of Endocrinology, Boston Children's Hospital, Boston, MA 02115, USA.
  • 3 Division of Genetics and Genomics, Boston Children's Hospital, Boston, MA 02115, USA; The Manton Center for Orphan Disease Research, Boston Children's Hospital, Boston, MA 02115, USA.
  • 4 Division of Genetics, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA.
  • 5 Division of Gastroenterology, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA.
  • 6 Department of Ophthalmology, Boston Children's Hospital, Boston, MA 02115, USA.
  • 7 Division of Gastroenterology, Boston Children's Hospital, Boston, MA 02115, USA; Department of Pediatrics, Harvard Medical School, Boston, MA 02115, USA.
  • 8 Department of Pathology, Boston Children's Hospital, Boston, MA 02115, USA.
  • 9 Division of Endocrinology, Boston Children's Hospital, Boston, MA 02115, USA; Department of Pediatrics, Harvard Medical School, Boston, MA 02115, USA; Harvard Stem Cell Institute, Cambridge, MA 02138, USA.
  • 10 Division of Newborn Medicine, Boston Children's Hospital, Boston, MA 02115, USA; Division of Genetics and Genomics, Boston Children's Hospital, Boston, MA 02115, USA; The Manton Center for Orphan Disease Research, Boston Children's Hospital, Boston, MA 02115, USA; Department of Pediatrics, Harvard Medical School, Boston, MA 02115, USA. Electronic address: pagrawal@enders.tch.harvard.edu.
PMID: 29909964 DOI: 10.1016/j.ajhg.2018.05.007
Abstract

Homozygous nonsense mutations in WNT2B were identified in three individuals from two unrelated families with severe, neonatal-onset osmotic diarrhea after whole-exome Sequencing was performed on trios from the two families. Intestinal biopsy samples from affected individuals were used for histology and immunofluorescence and to generate enteroids ex vivo. Histopathologic evaluation demonstrated chronic inflammatory changes in the stomach, duodenum, and colon. Immunofluorescence demonstrated diminished staining for OLFM4, a marker for intestinal stem cells (ISCs). The enteroids generated from WNT2B-deficient intestinal epithelium could not be expanded and did not survive passage. Addition of CHIR-99021 (a GSK3A and GSK3B inhibitor and activator of canonical Wnt/β-catenin signaling) could not rescue WNT2B-deficient enteroids. Addition of supplemental recombinant murine WNT2B was able to perpetuate small enteroids for multiple passages but failed to expand their number. Enteroids showed a 10-fold increase in the expression of LEF1 mRNA and a 100-fold reduction in TLR4 expression, compared with controls by quantitative RT-PCR, indicating alterations in canonical Wnt and microbial pattern-recognition signaling. In summary, individuals with homozygous nonsense mutations in WNT2B demonstrate severe intestinal dysregulation associated with decreased ISC number and function, likely explaining their diarrheal phenotype. WNT2B deficiency should be considered for individuals with neonatal-onset diarrhea.

Keywords

CODE; Lgr5; OLFM4; TLR4; WNT2B; congenital diarrhea and enteropathy; diarrhea; intestinal stem cells.

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