title: Prevalence of the 35delG mutation in deaf South Brazilian infants submitted to cochlear implantation.
abstract: OBJECTIVE
  Determine the prevalence of 35delG mutation in GJB2 gene in patients with prelingual deafness of no defined etiology whose underwent cochlear implant in the Otolaryngology Department at the Hospital de Clínicas de Porto Alegre and compare the speech recognition index using an open-set of sentences according to the presence or absence of the 35delG mutation.
  
  
  METHODS
  Cross-sectional study nested in a cohort. Were analyzed 37 patients with indeterminate etiology for deafness that underwent to cochlear implant. DNA was extracted and the mutations were studied using Polymerase Chain Reaction followed by gene sequencing.
  
  
  RESULTS
  The prevalence of 35delG mutation was 11%. The speech recognition index was 72% in the group with 35delG mutation, and 30% in the group without this mutation (p>0.05).
  
  
  CONCLUSIONS
  Prevalence of 35delG mutation in this study confirmed findings in the Brazilian literature. There was a clinically significant difference in hearing performance in patients with 35delG. Absence of statistical significance in this result might be attributed to the small number of patients with 35delG in our sample.
authors.affiliation: Federal University of Rio Grande do Sul, Medicine School, Otolaryngology Department at the Hospital de Clínicas, Porto Alegre, RS, Brazil. lhcmotta@yahoo.com.br
authors.forename: Luiz Henrique Campos
authors.initials: LH
authors.lastname: da Motta
authors.forename: Têmis Maria
authors.initials: TM
authors.lastname: Félix
authors.forename: Liliane Todeschini
authors.initials: LT
authors.lastname: de Souza
authors.forename: Michelle
authors.initials: M
authors.lastname: Lavinsky-Wolff
authors.forename: Fabiana Moura
authors.initials: FM
authors.lastname: Costa-Motta
authors.forename: Mauren Rocha
authors.initials: MR
authors.lastname: de Faria
authors.forename: Luiz
authors.initials: L
authors.lastname: Lavinsky
mesh_terms: D001299:Audiometry / Q000379:methods; D001309:Auditory Threshold; D001938:Brazil / Q000453:epidemiology; D016022:Case-Control Studies; D019929:Cochlear Implantation / Q000379:methods; D003054:Cochlear Implants; D000072259:Connexin 26; D017630:Connexins / Q000235:genetics*; D003430:Cross-Sectional Studies; D003638:Deafness / Q000235:genetics* / Q000503:physiopathology / Q000601:surgery*; D005260:Female; D005500:Follow-Up Studies; D020022:Genetic Predisposition to Disease / Q000453:epidemiology*; D006801:Humans; D007223:Infant; D008297:Male; D009154:Mutation; D018579:Patient Selection; D015995:Prevalence; D012016:Reference Values; D018570:Risk Assessment; D013067:Speech Perception / Q000502:physiology; D018709:Statistics, Nonparametric; D016896:Treatment Outcome; D000097004:Gap Junction delta-2 Protein
chemical_list: D000072259:Connexin 26; D017630:Connexins; D000097004:Gap Junction delta-2 Protein; C000607042:GJB2 protein, human