title: Absence of GJB6 mutations in Indian patients with non-syndromic hearing loss.
abstract: OBJECTIVE
  Hearing loss is the most frequent sensory defect in human being. Genetic factors account for at least half of all cases of profound congenital deafness. The 13q11-q12 region contains the GJB2 and GJB6 genes, which code connexin 26 (CX26) and connexin 30 (CX30) proteins, respectively. Mutations in the gene GJB2, encoding the gap junction protein connexin 26, are considered to be responsible for up to 50% of familial cases of autosomal recessive non-syndromic hearing loss and for up to 15-30% of the sporadic cases. It has also been reported that mutations in the GJB6 gene contribute to autosomal recessive and autosomal dominant hearing defects in many populations. The 342-kb deletion [del(GJB6-D13S1830)] of the Cx30 gene is the second most common connexin mutation after the CX26 mutations in some NSHL populations. The aim of this study was to screen GJB6 gene mutations in Asian Indian patients with autosomal non-syndromic hearing loss.
  
  
  METHODS
  We screened 203 non-syndromic hearing loss patients, who were negative for homozygous mutations in GJB2 gene, for GJB6-D13S1830 deletion and mutations in coding regions of GJB6 using polymerase chain reaction, denaturing high performance liquid chromatography and direct sequencing.
  
  
  RESULTS
  No deleterious mutation in GJB6 gene was detected in our study cohort.
  
  
  CONCLUSIONS
  The present data demonstrated that mutations in the GJB6 gene are unlikely to be a major cause of non-syndromic deafness in Asian Indians.
authors.affiliation: Department of Otolaryngology, Post Graduate Institute of Medical Education and Research, Chandigarh 160012, India.
authors.forename: Seema
authors.initials: S
authors.lastname: Bhalla
authors.forename: Rajni
authors.initials: R
authors.lastname: Sharma
authors.forename: Gaurav
authors.initials: G
authors.lastname: Khandelwal
authors.forename: Naresh K
authors.initials: NK
authors.lastname: Panda
authors.forename: Madhu
authors.initials: M
authors.lastname: Khullar
mesh_terms: D001301:Audiometry, Pure-Tone; D016022:Case-Control Studies; D002851:Chromatography, High Pressure Liquid; D015331:Cohort Studies; D000072259:Connexin 26; D000075302:Connexin 30; D017630:Connexins / Q000235:genetics*; D005260:Female; D017353:Gene Deletion; D034381:Hearing Loss / Q000453:epidemiology / Q000235:genetics*; D006801:Humans; D007194:India; D008297:Male; D009154:Mutation; D016133:Polymerase Chain Reaction; D017421:Sequence Analysis
chemical_list: D000075302:Connexin 30; D017630:Connexins; C000607042:GJB2 protein, human; C491020:GJB6 protein, human; D000072259:Connexin 26