PUBLICATION

Homozygous WASHC4 variant in two sisters causes a syndromic phenotype defined by dysmorphisms, intellectual disability, profound developmental disorder, and skeletal muscle involvement

Authors
Gangfuß, A., Czech, A., Hentschel, A., Münchberg, U., Horvath, R., Töpf, A., O'Heir, E., Lochmüller, H., Stehling, F., Kiewert, C., Sickmann, A., Kuechler, A., Kaiser, F., Kölbel, H., Christiansen, J., Schara-Schmidt, U., Roos, A.
ID
ZDB-PUB-211003-4
Date
2021
Source
The Journal of pathology   256(1): 93-107 (Journal)
Registered Authors
Horvath, Rita
Keywords
Coherent Anti-Stokes Raman Scattering microscopy, KIAA1033, WASHC4, dysmorphisms, fibroblast proteomics, intellectual disability, muscle autophagy, valosin containing protein
MeSH Terms
  • Child
  • Developmental Disabilities/complications
  • Developmental Disabilities/diagnosis
  • Developmental Disabilities/genetics*
  • Exome Sequencing/methods
  • Humans
  • Intellectual Disability/diagnosis
  • Intellectual Disability/genetics*
  • Muscle, Skeletal/metabolism
  • Muscle, Skeletal/pathology*
  • Mutation/genetics*
  • Pedigree
  • Phenotype
  • Proteomics/methods
  • Siblings
PubMed
34599609 Full text @ J. Pathol.
Abstract
Recessive variants in WASHC4 are linked to intellectual disability complicated by poor language skills, short stature, and dysmorphic features. The protein encoded by WASHC4 is part of the Wiskott-Aldrich Syndrome Protein and SCAR Homolog family, colocalizes with actin in cells and promotes Arp2/3-dependent actin polymerization in vitro. Functional studies in a zebrafish model suggested that WASHC4 knockdown may also affect skeletal muscles by perturbing protein clearance. However, skeletal muscle involvement has not been reported so far in patients, and precise biochemical studies allowing a deeper understanding of the molecular etiology of the disease are still lacking. Here, we report two siblings with a homozygous WASHC4 variant expanding the clinical spectrum of the disease and provide a phenotypical comparison with cases reported in the literature. Proteomic profiling of fibroblasts of the WASHC4-deficient patient revealed dysregulation of proteins relevant for the maintenance of the neuromuscular axis. Immunostaining on a muscle biopsy derived from the same patient confirmed dysregulation of proteins relevant for proper muscle function thus highlighting an affliction of muscle cells upon loss of functional WASHC4. Results of histological and Coherent Anti-Stokes Raman Scattering microscopic studies support the concept of a functional role of the WASHC4 protein in humans by altering protein processing and clearance. Results of the proteomic analysis confirmed key molecular players in vitro and highlighted - for the first time - the involvement of skeletal muscle in patients. This article is protected by copyright. All rights reserved.
Genes / Markers
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Expression
Phenotype
Mutations / Transgenics
Human Disease / Model
Sequence Targeting Reagents
Fish
Antibodies
Orthology
Engineered Foreign Genes
Mapping