title: The clinical features of patients with the homozygous 235delC and the compound-heterozygous Y136X/G45E of the GJB2 mutations (Connexin 26) in cochlear implant recipients.
abstract: OBJECTIVE
  This study aimed to investigate the prevalence of GJB2 gene for the 235delC mutations, the clinical features and the outcomes of patients who had undergone cochlear implantation.
  
  
  METHODS
  We have sequenced the coding region of GJB2 gene for 135 patients with sensorineural deaf from September 2000 to May 2009. Of the 135 patients, the patients with the homozygous 235delC and the compound-heterozygous Y136X/G45E were detected and were investigated clinically.
  
  
  RESULTS
  The GJB2 gene for the 235delC mutations was found in 39 alleles of 270 alleles (14.4%), especially for the homozygous of 235delC was detected in 26 alleles (9.6%), the single heterozygous of 235delC was 1 allele (0.4%), the compound heterozygous of 235delC was found in 12 alleles (4.4%). Of 16 subjects (29 alleles) with the homozygous 235delC and the compound-heterozygous Y136X/G45E, 2 subjects (4 alleles) were found to have complications. All of the subjects were found to show severe hearing loss and some of them have indicated progressive hearing loss. However, they showed better performance regarding the thresholds after implantation. The subjects with complications, although, suggested poorer performance in the auditory speech performance.
  
  
  CONCLUSIONS
  The findings of poorer outcomes might depend on complications and brain functions. In addition, considering the blood test parameters, an independent elevated LDH and ChE at diagnosis were found to be associated with hereditary enzyme's metabolic disease. Therefore, the value of LDH measurements in patients might be a helpful predictive parameter in hereditary diseases.
authors.affiliation: The Open University of Japan, Japan. yoshikaway@aol.com
authors.forename: Satoko
authors.initials: S
authors.lastname: Yoshikawa
authors.forename: Atsushi
authors.initials: A
authors.lastname: Kawano
authors.forename: Chieri
authors.initials: C
authors.lastname: Hayashi
authors.forename: Nobuhiro
authors.initials: N
authors.lastname: Nishiyama
authors.forename: Sachie
authors.initials: S
authors.lastname: Kawaguchi
authors.forename: Hiroko
authors.initials: H
authors.lastname: Furuse
authors.forename: Katsuhisa
authors.initials: K
authors.lastname: Ikeda
authors.forename: Mamoru
authors.initials: M
authors.lastname: Suzuki
authors.forename: Masahumi
authors.initials: M
authors.lastname: Nakagawa
mesh_terms: D000328:Adult; D000483:Alleles; D002675:Child, Preschool; D003054:Cochlear Implants; D000072259:Connexin 26; D017630:Connexins / Q000235:genetics*; D005260:Female; D017353:Gene Deletion; D006309:Hearing; D006319:Hearing Loss, Sensorineural / Q000097:blood / Q000150:complications / Q000235:genetics* / Q000601:surgery; D006579:Heterozygote; D006720:Homozygote; D006801:Humans; D008297:Male; D009154:Mutation; D012984:Software; D016896:Treatment Outcome
chemical_list: D017630:Connexins; C000607042:GJB2 protein, human; D000072259:Connexin 26