title: Phenotype analysis of an Australian DFNA9 family with the 1109N COCH mutation.
abstract: OBJECTIVE
  We studied the clinical characteristics of an Australian family with an autosomal dominant sensorineural hearing impairment (DFNA9) caused by an I109N mutation in COCH.
  
  
  METHODS
  Retrospective analyses of audiometric data from 8 mutation carriers of an Australian DFNA9 family with the I109N COCH mutation were performed. Cross-sectional hearing levels related to age, age-related typical audiograms, and speech recognition scores related to age and to the level of hearing impairment were investigated. Data were compared to those obtained in previously identified DFNA9 families with P51S, V66G, G87W, G88E, I109T, and C542F COCH mutations.
  
  
  RESULTS
  Deterioration of hearing in the I109N mutation carriers started before the age of 40 years. The audiometric characteristics of the I109N mutation carriers are essentially similar to those previously established in I109T mutation carriers and, to a lesser extent, in P51S, G87W, and G88E mutation carriers.
  
  
  CONCLUSIONS
  The phenotype associated with the I109N COCH mutation is largely similar to that associated with the I109T, P51S, G87W, and G88E mutation carriers. However, subtle differences seem to exist in terms of age of onset and rate of progression.
authors.affiliation: Department of Otorhinolaryngology, Radboud University Nijmegen Medical Center, Nijmegen, The Netherlands.
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Pauw
authors.forename: Patrick L M
authors.initials: PL
authors.lastname: Huygen
authors.forename: Gordon M
authors.initials: GM
authors.lastname: Colditz
authors.forename: Cor W R J
authors.initials: CW
authors.lastname: Cremers
mesh_terms: D000328:Adult; D001301:Audiometry, Pure-Tone; D001302:Audiometry, Speech; D001309:Auditory Threshold; D001315:Australia / Q000453:epidemiology; D003430:Cross-Sectional Studies; D004247:DNA / Q000235:genetics*; D004252:DNA Mutational Analysis; D016326:Extracellular Matrix Proteins; D005190:Family; D005260:Female; D020022:Genetic Predisposition to Disease; D006319:Hearing Loss, Sensorineural / Q000453:epidemiology / Q000235:genetics* / Q000503:physiopathology; D006579:Heterozygote; D006801:Humans; D008297:Male; D009154:Mutation; D010375:Pedigree; D010641:Phenotype; D015995:Prevalence; D011506:Proteins / Q000235:genetics*; D012189:Retrospective Studies
chemical_list: C110668:COCH protein, human; D016326:Extracellular Matrix Proteins; D011506:Proteins; D004247:DNA