1. Academic Validation
  2. Homozygous DBF4 mutation as a cause for severe congenital neutropenia

Homozygous DBF4 mutation as a cause for severe congenital neutropenia

  • J Allergy Clin Immunol. 2023 Feb 23;S0091-6749(23)00230-0. doi: 10.1016/j.jaci.2023.02.016.
Mathijs Willemsen 1 John S Barber 1 Erika Van Nieuwenhove 2 Frederik Staels 3 Margaux Gerbaux 4 Julika Neumann 1 Teresa Prezzemolo 1 Emanuela Pasciuto 1 Vasiliki Lagou 1 Nancy Boeckx 5 Jessica Filtjens 6 Amber De Visscher 6 Patrick Matthys 6 Rik Schrijvers 7 Thomas Tousseyn 8 Mark O'Driscoll 9 Giorgia Bucciol 10 Susan Schlenner 11 Isabelle Meyts 12 Stephanie Humblet-Baron 13 Adrian Liston 14
Affiliations

Affiliations

  • 1 Department of Microbiology, Immunology and Transplantation, Laboratory of Adaptive Immunity, KU Leuven, Leuven, Belgium; VIB-KU Leuven Center for Brain and Disease Research, Leuven, Belgium.
  • 2 Department of Microbiology, Immunology and Transplantation, Laboratory of Adaptive Immunity, KU Leuven, Leuven, Belgium; VIB-KU Leuven Center for Brain and Disease Research, Leuven, Belgium; Department of Pediatrics, University Hospitals Leuven, Leuven, Belgium.
  • 3 Department of Microbiology, Immunology and Transplantation, Laboratory of Adaptive Immunity, KU Leuven, Leuven, Belgium; Department of Microbiology, Immunology and Transplantation, Allergy and Clinical Immunology Research Group, KU Leuven, Leuven, Belgium.
  • 4 Department of Microbiology, Immunology and Transplantation, Laboratory of Adaptive Immunity, KU Leuven, Leuven, Belgium; Pediatric Department, Academic Children Hospital Queen Fabiola, Université Libre de Bruxelles, Brussels, Belgium.
  • 5 Department of Laboratory Medicine, University Hospitals Leuven, Leuven, Belgium.
  • 6 Department of Microbiology, Immunology and Transplantation, Laboratory of Immunobiology, Rega Institute for Medical Research, KU Leuven, Leuven, Belgium.
  • 7 Department of Microbiology, Immunology and Transplantation, Allergy and Clinical Immunology Research Group, KU Leuven, Leuven, Belgium.
  • 8 Department of Pathology, University Hospitals Leuven, Leuven, Belgium.
  • 9 Human DNA Damage Response Disorders Group, Genome Damage and Stability Centre, University of Sussex, Brighton, BN1 9RQ, United Kingdom.
  • 10 Department of Microbiology, Immunology and Transplantation, Laboratory for Inborn Errors of Immunity, KU Leuven, Leuven, Belgium; Department of Pediatrics, Division of Primary Immunodeficiencies, University Hospitals Leuven, Leuven, Belgium.
  • 11 Department of Microbiology, Immunology and Transplantation, Laboratory of Adaptive Immunity, KU Leuven, Leuven, Belgium.
  • 12 Department of Microbiology, Immunology and Transplantation, Laboratory for Inborn Errors of Immunity, KU Leuven, Leuven, Belgium; Department of Pediatrics, Division of Primary Immunodeficiencies, University Hospitals Leuven, Leuven, Belgium; ERN-RITA Core Center Member.
  • 13 Department of Microbiology, Immunology and Transplantation, Laboratory of Adaptive Immunity, KU Leuven, Leuven, Belgium. Electronic address: stephanie.humbletbaron@kuleuven.be.
  • 14 Department of Microbiology, Immunology and Transplantation, Laboratory of Adaptive Immunity, KU Leuven, Leuven, Belgium; VIB-KU Leuven Center for Brain and Disease Research, Leuven, Belgium; Immunology Programme, The Babraham Institute, Babraham Research Campus, Cambridge, CB22 3AT United Kingdom. Electronic address: al989@cam.ac.uk.
Abstract

Background: Severe congenital neutropenia presents with recurrent infections early in life due to arrested granulopoiesis. Multiple genetic defects are known to block granulocyte differentiation, however a genetic cause remains unknown in approximately 40% of cases.

Objective: We aimed to characterize a patient with severe congenital neutropenia and syndromic features without a genetic diagnosis.

Methods: Whole exome Sequencing results were validated using flow cytometry, Western blotting, co-immunoprecipitation, quantitative PCR, cell cycle and proliferation analysis of lymphocytes and fibroblasts and granulocytic differentiation of primary CD34+ and HL-60 cells.

Results: We identified a homozygous missense mutation in DBF4 in a patient with mild extra-uterine growth retardation, facial dysmorphism and severe congenital neutropenia. DBF4 is the regulatory subunit of the CDC7 kinase, together known as DBF4-dependent kinase (DDK), the complex essential for DNA replication initiation. The variant allele demonstrated impaired ability to bind CDC7, resulting in decreased DDK-mediated phosphorylation, defective S phase entry and progression and impaired differentiation of granulocytes associated with activation of the p53-p21 pathway. The introduction of WT DBF4 into patient CD34+ cells rescued the promyelocyte differentiation arrest.

Conclusion: Hypomorphic DBF4 mutation causes autosomal recessive severe congenital neutropenia with syndromic features.

Keywords

DBF4; DNA replication; facial dysmorphism; genetics; inborn errors of immunity; mutation; neutropenia; perturbed growth; primary immunodeficiency.

Figures
Products
  • Cat. No.
    Product Name
    Description
    Target
    Research Area
  • HY-100888
    99.94%, CDC7抑制剂
    CDK