title: Focal sclerosis of semicircular canals with severe DFNA9 hearing impairment caused by a P51S COCH-mutation: is there a link?
abstract: OBJECTIVE
  Focal sclerosis of one or more semicircular canals on computed tomographic (CT) scans and a corresponding signal loss on magnetic resonance (MR) imaging are radiologic lesions that are linked to patients who are suffering from advanced otovestibular impairment caused by hereditary DFNA9 hearing loss.
  
  
  BACKGROUND
  DFNA9 is a hereditary hearing loss that is characterized by late-onset progressive imbalance and hearing deterioration, caused by mutations in the COCH gene. To date, no radiologic lesions have been associated with this condition.
  
  
  METHODS
  A retrospective chart review
  
  
  METHODS
  Tertiary referral center
  
  
  METHODS
  The radiologic data of 9 patients who presented between 2007 and 2012 with otovestibular deterioration caused by a mutation in the COCH gene were reviewed.
  
  
  RESULTS
  All 9 subjects were carriers of the same c.151C > T, p.Pro51Ser (P51S) - missense mutation in the COCH gene. In 8 of them similar sclerotic lesions and/or narrowing were demonstrated in one or more semicircular canals on computed tomography CT scan, with a signal loss at corresponding areas on T2-weighted magnetic resonance (MR) images. In 1 patient, the posterior part of the vestibule was also affected. The posterior canals were affected in most cases (58%), compared with the superior (21%) and lateral canals (16%) or the vestibule (5%). Only 68.4% of the lesions on MR images were also visible on CT scans, suggesting a fibrotic process without calcification. Ears presenting radiologic lesions showed significantly more severe hearing loss (median PTA 104 dB HL) compared with unaffected ears (58 dB HL).
  
  
  CONCLUSIONS
  Eight of 9 subjects with the same P51S mutation in the COCH gene showed similar radiologic lesions, affecting the PSCC in the majority of the cases. These radiologic abnormalities occurred in more advanced stages of the otovestibular deterioration, supporting the hypothesis that these lesions might represent the end phase of a low-grade chronic inflammation or protein deposition. A new phenotypic and characteristic radiologic feature of DFNA9 has been discovered.
authors.affiliation: *Department of Otorhinolaryngology, Campus Virga Jesse, †Department of Radiology, Jessa Hospital, Hasselt; ‡Department of Biomedical Sciences, Medical Genetics Centre, University of Antwerp, Antwerp; and §The Eargroup, Antwerp-Deurne, Belgium.
authors.forename: Sebastien Pierre Janssens
authors.initials: SP
authors.lastname: de Varebeke
authors.forename: Bruno
authors.initials: B
authors.lastname: Termote
authors.forename: Guy
authors.initials: G
authors.lastname: Van Camp
authors.forename: Paul J
authors.initials: PJ
authors.lastname: Govaerts
authors.forename: Steven
authors.initials: S
authors.lastname: Schepers
authors.forename: Tony
authors.initials: T
authors.lastname: Cox
authors.forename: Kristof
authors.initials: K
authors.lastname: Deben
authors.forename: Katrien
authors.initials: K
authors.lastname: Ketelslagers
authors.forename: Geert
authors.initials: G
authors.lastname: Souverijns
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D016326:Extracellular Matrix Proteins / Q000235:genetics*; D005192:Family Health; D005260:Female; D034381:Hearing Loss / Q000175:diagnosis / Q000000981:diagnostic imaging* / Q000235:genetics*; D006801:Humans; D008297:Male; D008875:Middle Aged; D020125:Mutation, Missense; D010641:Phenotype; D012189:Retrospective Studies; D012598:Sclerosis / Q000235:genetics; D012665:Semicircular Canals / Q000000981:diagnostic imaging*; D012720:Severity of Illness Index; D014057:Tomography, X-Ray Computed
chemical_list: C110668:COCH protein, human; D016326:Extracellular Matrix Proteins