1. Academic Validation
  2. EXTL3 mutations cause skeletal dysplasia, immune deficiency, and developmental delay

EXTL3 mutations cause skeletal dysplasia, immune deficiency, and developmental delay

  • J Exp Med. 2017 Mar 6;214(3):623-637. doi: 10.1084/jem.20161525.
Stefano Volpi 1 Yasuhiro Yamazaki 2 Patrick M Brauer 3 Ellen van Rooijen 4 Atsuko Hayashida 5 Anne Slavotinek 6 Hye Sun Kuehn 7 Maja Di Rocco 8 Carlo Rivolta 9 Ileana Bortolomai 10 11 Likun Du 12 Kerstin Felgentreff 12 Lisa Ott de Bruin 12 Kazutaka Hayashida 5 George Freedman 13 Genni Enza Marcovecchio 10 Kelly Capuder 12 Prisni Rath 14 Nicole Luche 12 Elliott J Hagedorn 4 Antonella Buoncompagni 1 Beryl Royer-Bertrand 9 15 Silvia Giliani 16 Pietro Luigi Poliani 17 Luisa Imberti 18 Kerry Dobbs 2 Fabienne E Poulain 19 Alberto Martini 1 John Manis 20 Robert J Linhardt 21 Marita Bosticardo 10 Sergio Damian Rosenzweig 7 Hane Lee 22 Jennifer M Puck 13 Juan Carlos Zúñiga-Pflücker 3 Leonard Zon 4 Pyong Woo Park 5 Andrea Superti-Furga 23 Luigi D Notarangelo 24
Affiliations

Affiliations

  • 1 Unita' Operativa Pediatria 2, Istituto Giannina Gaslini, 16148 Genoa, Italy.
  • 2 Laboratory of Host Defenses, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, 20892.
  • 3 Department of Immunology, Sunnybrook Research Institute, University of Toronto, Toronto, Ontario M5S, Canada.
  • 4 Stem Cell Program, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115.
  • 5 Division of Respiratory Diseases, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115.
  • 6 Department of Pediatrics, Division of Genetics, University of California, San Francisco, San Francisco, CA 94143.
  • 7 Department of Laboratory Medicine, National Institutes of Health Clinical Center, National Institutes of Health, Bethesda, MD, 20892.
  • 8 Unit of Rare Diseases, Department of Pediatrics, Istituto Giannina Gaslini, 16148 Genoa, Italy.
  • 9 Department of Computational Biology, Unit of Medical Genetics, University of Lausanne, 1015 Lausanne, Switzerland.
  • 10 San Raffaele Telethon Institute for Gene Therapy, Istituto di Ricerca e Cura a Carattere Scientifico San Raffaele Scientific Institute, 20132 Milan, Italy.
  • 11 Consiglio Nazionale delle Ricerche-Istituto di Ricerca Genetica e Biomedica, Milan Unit, 20138 Milan, Italy.
  • 12 Division of Immunology, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115.
  • 13 Department of Pediatrics, University of California, San Francisco, San Francisco, CA 94143.
  • 14 Tata Consultancy Services Innovation Labs, Telangana 500081, India.
  • 15 Division of Genetic Medicine, Lausanne University Hospital, University of Lausanne, 1015 Lausanne, Switzerland.
  • 16 A. Nocivelli Institute for Molecular Medicine, University of Brescia, 25123 Brescia, Italy.
  • 17 Department of Molecular and Translational Medicine, University of Brescia, 25123 Brescia, Italy.
  • 18 Centro di ricerca emato-oncologica AIL, Spedali Civili, 25123 Brescia, Italy.
  • 19 Department of Biological Sciences, University of South Carolina, Columbia, SC 29208.
  • 20 Department of Laboratory Medicine, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115.
  • 21 Department of Chemistry and Chemical Biology, Rensselaer Polytechnic Institute, Troy, NY 12180.
  • 22 Department of Pathology and Laboratory Medicine, University of California at Los Angeles, Los Angeles, CA 90095.
  • 23 Division of Genetic Medicine, Lausanne University Hospital, University of Lausanne, 1015 Lausanne, Switzerland luigi.notarangelo2@nih.gov asuperti@unil.ch.
  • 24 Laboratory of Host Defenses, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, 20892 luigi.notarangelo2@nih.gov asuperti@unil.ch.
Abstract

We studied three patients with severe skeletal dysplasia, T cell immunodeficiency, and developmental delay. Whole-exome Sequencing revealed homozygous missense mutations affecting exostosin-like 3 (EXTL3), a Glycosyltransferase involved in heparan sulfate (HS) biosynthesis. Patient-derived fibroblasts showed abnormal HS composition and altered Fibroblast Growth Factor 2 signaling, which was rescued by overexpression of wild-type EXTL3 cDNA. Interleukin-2-mediated STAT5 phosphorylation in patients' lymphocytes was markedly reduced. Interbreeding of the extl3-mutant zebrafish (box) with Tg(rag2:green fluorescent protein) transgenic zebrafish revealed defective thymopoiesis, which was rescued by injection of wild-type human EXTL3 RNA. Targeted differentiation of patient-derived induced pluripotent stem cells showed a reduced expansion of lymphohematopoietic progenitor cells and defects of thymic epithelial progenitor cell differentiation. These data identify EXTL3 mutations as a novel cause of severe immune deficiency with skeletal dysplasia and developmental delay and underline a crucial role of HS in thymopoiesis and skeletal and brain development.

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