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Espin gene (ESPN) mutations associated with autosomal dominant hearing loss cause defects in microvillar elongation or organisation
  1. F Donaudy1,
  2. L Zheng2,
  3. R Ficarella1,
  4. E Ballana3,
  5. M Carella4,
  6. S Melchionda4,
  7. X Estivill3,
  8. J R Bartles2,
  9. P Gasparini1
  1. 1TIGEM-Telethon Institute of Genetics and Medicine, Naples, Italy
  2. 2Department of Cell and Molecular Biology, Feinberg School of Medicine and Institute for Neuroscience, Northwestern University, Chicago, Illinois, USA
  3. 3Genes and Disease Programme, Centre for Genomic Regulation (CRG), Pompeu Fabra University (UPF), Barcelona, Spain
  4. 4Servizio di Genetica Medica, IRCCS-Hospital “CSS”, San Giovanni Rotondo, Italy
  1. Correspondence to:
 Dr Paolo Gasparini
 Telethon Institute of Genetics and Medicine, Via P Castellino III, Torino I-71013, Italy; gasparini{at}tigem.it

Abstract

Background: Espins are actin bundling proteins present in hair cell stereocilia. A recessive mutation in the espin gene (Espn) has been detected in the jerker mouse and causes deafness, vestibular dysfunction, and hair cell degeneration. More recently mutations in the human espin gene (ESPN) have been described in two families affected by autosomal recessive hearing loss and vestibular areflexia.

Objective: To report the identification of four additional ESPN mutations (S719R, D744N, R774Q, and delK848) in patients affected by autosomal dominant hearing loss without vestibular involvement.

Results: To determine whether the mutated ESPN alleles affected the biological activity of the corresponding espin proteins in vivo, their ability to target and elongate the parallel actin bundles of brush border microvilli was investigated in transfected LLC-PK1-CL4 epithelial cells. For three mutated alleles clear abnormalities in microvillar length or distribution were obtained.

Conclusions: The results further strengthen the causative role of the espin gene in non-syndromic hearing loss and add new insights into espin structure and function.

  • espin
  • actin
  • hearing loss
  • autosomal dominant deafness

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Footnotes

  • Conflicts of interest: none declared

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