title: A congenital neutrophil defect syndrome associated with mutations in VPS45.
abstract: BACKGROUND
  Neutrophils are the predominant phagocytes that provide protection against bacterial and fungal infections. Genetically determined neutrophil disorders confer a predisposition to severe infections and reveal novel mechanisms that control vesicular trafficking, hematopoiesis, and innate immunity.
  
  
  METHODS
  We clinically evaluated seven children from five families who had neutropenia, neutrophil dysfunction, bone marrow fibrosis, and nephromegaly. To identify the causative gene, we performed homozygosity mapping using single-nucleotide polymorphism arrays, whole-exome sequencing, immunoblotting, immunofluorescence, electron microscopy, a real-time quantitative polymerase-chain-reaction assay, immunohistochemistry, flow cytometry, fibroblast motility assays, measurements of apoptosis, and zebrafish models. Correction experiments were performed by transfecting mutant fibroblasts with the nonmutated gene.
  
  
  RESULTS
  All seven affected children had homozygous mutations (Thr224Asn or Glu238Lys, depending on the child's ethnic origin) in VPS45, which encodes a protein that regulates membrane trafficking through the endosomal system. The level of VPS45 protein was reduced, as were the VPS45 binding partners rabenosyn-5 and syntaxin-16. The level of β1 integrin was reduced on the surface of VPS45-deficient neutrophils and fibroblasts. VPS45-deficient fibroblasts were characterized by impaired motility and increased apoptosis. A zebrafish model of vps45 deficiency showed a marked paucity of myeloperoxidase-positive cells (i.e., neutrophils). Transfection of patient cells with nonmutated VPS45 corrected the migration defect and decreased apoptosis.
  
  
  CONCLUSIONS
  Defective endosomal intracellular protein trafficking due to biallelic mutations in VPS45 underlies a new immunodeficiency syndrome involving impaired neutrophil function. (Funded by the National Human Genome Research Institute and others.).
authors.affiliation: Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA.
authors.forename: Thierry
authors.initials: T
authors.lastname: Vilboux
authors.forename: Atar
authors.initials: A
authors.lastname: Lev
authors.forename: May Christine V
authors.initials: MC
authors.lastname: Malicdan
authors.forename: Amos J
authors.initials: AJ
authors.lastname: Simon
authors.forename: Päivi
authors.initials: P
authors.lastname: Järvinen
authors.forename: Tomas
authors.initials: T
authors.lastname: Racek
authors.forename: Jacek
authors.initials: J
authors.lastname: Puchalka
authors.forename: Raman
authors.initials: R
authors.lastname: Sood
authors.forename: Blake
authors.initials: B
authors.lastname: Carrington
authors.forename: Kevin
authors.initials: K
authors.lastname: Bishop
authors.forename: James
authors.initials: J
authors.lastname: Mullikin
authors.forename: Marjan
authors.initials: M
authors.lastname: Huizing
authors.forename: Ben Zion
authors.initials: BZ
authors.lastname: Garty
authors.forename: Eran
authors.initials: E
authors.lastname: Eyal
authors.forename: Baruch
authors.initials: B
authors.lastname: Wolach
authors.forename: Ronit
authors.initials: R
authors.lastname: Gavrieli
authors.forename: Amos
authors.initials: A
authors.lastname: Toren
authors.forename: Michalle
authors.initials: M
authors.lastname: Soudack
authors.forename: Osama M
authors.initials: OM
authors.lastname: Atawneh
authors.forename: Tatiana
authors.initials: T
authors.lastname: Babushkin
authors.forename: Ginette
authors.initials: G
authors.lastname: Schiby
authors.forename: Andrew
authors.initials: A
authors.lastname: Cullinane
authors.forename: Camila
authors.initials: C
authors.lastname: Avivi
authors.forename: Sylvie
authors.initials: S
authors.lastname: Polak-Charcon
authors.forename: Iris
authors.initials: I
authors.lastname: Barshack
authors.forename: Ninette
authors.initials: N
authors.lastname: Amariglio
authors.forename: Gideon
authors.initials: G
authors.lastname: Rechavi
authors.forename: Jutte
authors.initials: J
authors.lastname: van der Werff ten Bosch
authors.forename: Yair
authors.initials: Y
authors.lastname: Anikster
authors.forename: Christoph
authors.initials: C
authors.lastname: Klein
authors.forename: William A
authors.initials: WA
authors.lastname: Gahl
authors.forename: Raz
authors.initials: R
authors.lastname: Somech
mesh_terms: D000818:Animals; D002648:Child; D011992:Endosomes / Q000378:metabolism; D006720:Homozygote; D006801:Humans; D007153:Immunologic Deficiency Syndromes / Q000151:congenital / Q000235:genetics* / Q000276:immunology; D009154:Mutation; D009503:Neutropenia / Q000151:congenital* / Q000235:genetics; D009504:Neutrophils / Q000502:physiology; D010641:Phenotype; D021381:Protein Transport; D033921:Vesicular Transport Proteins / Q000235:genetics* / Q000378:metabolism; D015027:Zebrafish
chemical_list: C498421:VPS45 protein, human; D033921:Vesicular Transport Proteins