Human Genetics

, Volume 118, Issue 1, pp 29–34

Targeted disruption of mouse Coch provides functional evidence that DFNA9 hearing loss is not a COCH haploinsufficiency disorder

  • Tomoko Makishima
  • Clara I. Rodriguez
  • Nahid G. Robertson
  • Cynthia C. Morton
  • Colin L. Stewart
  • Andrew J. Griffith
Original Investigation

DOI: 10.1007/s00439-005-0001-4

Cite this article as:
Makishima, T., Rodriguez, C.I., Robertson, N.G. et al. Hum Genet (2005) 118: 29. doi:10.1007/s00439-005-0001-4

Abstract

Dominant progressive hearing loss and vestibular dysfunction DFNA9 is caused by mutations of the human COCH gene. COCH encodes cochlin, a highly abundant secreted protein of unknown function in the inner ear. Cochlin has an N-terminal LCCL domain followed by two vWA domains, and all known DFNA9 mutations are either missense substitutions or an amino acid deletion in the LCCL domain. Here, we have characterized the auditory phenotype associated with a genomic deletion of mouse Coch downstream of the LCCL domain. Homozygous Coch−/− mice express no detectable cochlin in the inner ear. Auditory brainstem responses to click and pure-tone stimuli (8, 16, 32 kHz) were indistinguishable among wild type and homozygous Coch−/− mice. A Coch-LacZΔneo reporter allele detected Coch mRNA expression in nonsensory epithelial and stromal regions of the cochlea and vestibular labyrinth. These data provide functional evidence that DFNA9 is probably not caused by COCH haploinsufficiency, but via a dominant negative or gain-of-function effect, in nonsensory regions of the inner ear.

Keywords

COCHCochlinDFNA9DeafnessHearing loss

Copyright information

© Springer-Verlag 2005

Authors and Affiliations

  • Tomoko Makishima
    • 1
  • Clara I. Rodriguez
    • 2
  • Nahid G. Robertson
    • 3
  • Cynthia C. Morton
    • 3
  • Colin L. Stewart
    • 2
  • Andrew J. Griffith
    • 1
    • 4
  1. 1.Section on Gene Structure and FunctionNational Institute on Deafness and Other Communication Disorders, National Institutes of HealthRockvilleUSA
  2. 2.Cancer and Developmental Biology LaboratoryNational Cancer Institute, National Institutes of HealthFrederickUSA
  3. 3.Department of PathologyBrigham and Women’s Hospital and Harvard Medical SchoolBostonUSA
  4. 4.Hearing Section, National Institute on Deafness and Other Communication Disorders, National Institutes of HealthRockvilleUSA