PUBLICATION

A congenital neutrophil defect syndrome associated with mutations in VPS45

Authors
Vilboux, T., Lev, A., Malicdan, M.C., Simon, A.J., Järvinen, P., Racek, T., Puchalka, J., Sood, R., Carrington, B., Bishop, K., Mullikin, J., Huizing, M., Garty, B.Z., Eyal, E., Wolach, B., Gavrieli, R., Toren, A., Soudack, M., Atawneh, O.M., Babushkin, T., Schiby, G., Cullinane, A., Avivi, C., Polak-Charcon, S., Barshack, I., Amariglio, N., Rechavi, G., van der Werff ten Bosch, J., Anikster, Y., Klein, C., Gahl, W.A., and Somech, R.
ID
ZDB-PUB-130709-10
Date
2013
Source
New. Engl. J. Med.   369(1): 54-65 (Journal)
Registered Authors
Sood, Raman
Keywords
none
MeSH Terms
  • Animals
  • Child
  • Endosomes/metabolism
  • Homozygote
  • Humans
  • Immunologic Deficiency Syndromes/congenital
  • Immunologic Deficiency Syndromes/genetics*
  • Immunologic Deficiency Syndromes/immunology
  • Mutation
  • Neutropenia/congenital*
  • Neutropenia/genetics
  • Neutrophils/physiology
  • Phenotype
  • Protein Transport
  • Vesicular Transport Proteins/genetics*
  • Vesicular Transport Proteins/metabolism
  • Zebrafish
PubMed
23738510 Full text @ New Engl. J. Med.
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.)

Genes / Markers
Figures
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Expression
Phenotype
Mutations / Transgenics
Human Disease / Model
Sequence Targeting Reagents
Fish
Antibodies
Orthology
Engineered Foreign Genes
Mapping