Homozygous< /i> DBF4< //i> mutation as a cause of severe congenital neutropenia

Willemsen, Mathijs; Barber, John S; Van Nieuwenhove, Erika; Staels, Frederik; Gerbaux, Margaux; Neumann, Julika; Prezzemolo, Teresa; Pasciuto, Emanuela; Lagou, Vasiliki; Boeckx, Nancy; Filtjens, Jessica; De Visscher, Amber; Matthys, Patrick; Schrijvers, Rik; Tousseyn, Thomas; O'Driscoll, Mark; Bucciol, Giorgia; Schlenner, Susan; Meyts, Isabelle; Humblet-Baron, Stephanie; Liston, Adrian

doi:10.1016/j.jaci.2023.02.016

Homozygous< /i> DBF4< //i> mutation as a cause of severe congenital neutropenia

Author:

Willemsen, Mathijs

Barber, John S ; Van Nieuwenhove, Erika ; Staels, Frederik ; Gerbaux, Margaux ; Neumann, Julika ; Prezzemolo, Teresa ; Pasciuto, Emanuela ; Lagou, Vasiliki ; Boeckx, Nancy ; Filtjens, Jessica ; De Visscher, Amber ; Matthys, Patrick ; Schrijvers, Rik ; Tousseyn, Thomas ; O'Driscoll, Mark ; Bucciol, Giorgia ; Schlenner, Susan ; Meyts, Isabelle ; Humblet-Baron, Stephanie ; Liston, Adrian

Keywords:

Science & Technology, Life Sciences & Biomedicine, Allergy, Immunology, DBF4, DNA replication, inborn errors of immunity, pri-mary immunodeficiency, neutropenia, perturbed growth, facial dys-morphism, genetics, mutation, REPLICATION ORIGIN ACTIVATION, DNA-REPLICATION, CDC7 KINASE, S-PHASE, GROWTH-RETARDATION, MYELOID DIFFERENTIATION, HEMATOPOIETIC STEM, PROTEIN-KINASE, SHORT STATURE, PHOSPHORYLATION, facial dysmorphism, primary immunodeficiency, Humans, Cell Cycle Proteins, Protein Serine-Threonine Kinases, Saccharomyces cerevisiae Proteins, Mutation, Phosphorylation, ImmunAID - 779295;info:eu-repo/grantAgreement/EC/H2020/779295, STG/19/032#55510692, C16/17/010#54271312, G0A3218N#54517918, C16/18/007#54690355, 1107 Immunology, 3204 Immunology

Abstract:

BACKGROUND: Severe congenital neutropenia presents with recurrent infections early in life as a result of 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, coimmunoprecipitation, 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 DBF4 variant 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 wild-type DBF4 into patient CD34+ cells rescued the promyelocyte differentiation arrest. CONCLUSION: Hypomorphic DBF4 mutation causes autosomal-recessive severe congenital neutropenia with syndromic features.