title: Spectrum of GJB2 (Cx26) gene mutations in Iranian Azeri patients with nonsyndromic autosomal recessive hearing loss.
abstract: OBJECTIVE
  Hereditary hearing impairment is a genetically heterogeneous disorder. In spite of this, mutations in the GJB2 gene, encoding connexin 26 (Cx26), are a major cause of nonsyndromic recessive hearing loss in many countries and are largely dependent on ethnic groups. The purpose of our study was to characterize the type and prevalence of GJB2 mutations among Azeri population of Iran.
  
  
  METHODS
  Fifty families presenting autosomal recessive nonsyndromic hearing loss from Ardabil province of Iran were studied for mutations in GJB2 gene. All DNA samples were screened for c.35delG mutation by ARMS PCR. Samples from patients who were normal for c.35delG were analyzed for the other variations in GJB2 by direct sequencing. In the absence of mutation detection, GJB6 was screened for the del(GJB6-D13S1830) and del(GJB6-D13S1854).
  
  
  RESULTS
  Thirteen families demonstrated alteration in the Cx26 (26%). The 35delG mutation was the most common one, accounting for 69.2% (9 out of 13 families). All the detected families were homozygous for this mutation. Two families were homozygous for delE120 and 299-300delAT mutations. We also identified a novel mutation: c.463-464 delTA in 2 families resulting in a frame shift mutation.
  
  
  CONCLUSIONS
  Our results suggest that c.35delG mutation in the GJB2 gene is the most important cause of GJB2 related deafness in Iranian Azeri population.
authors.affiliation: Genetics Research Centre, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran.
authors.forename: Behzad
authors.initials: B
authors.lastname: Davarnia
authors.forename: Mojgan
authors.initials: M
authors.lastname: Babanejad
authors.forename: Zohreh
authors.initials: Z
authors.lastname: Fattahi
authors.forename: Nooshin
authors.initials: N
authors.lastname: Nikzat
authors.forename: Niloofar
authors.initials: N
authors.lastname: Bazazzadegan
authors.forename: Akbar
authors.initials: A
authors.lastname: Pirzade
authors.forename: Reza
authors.initials: R
authors.lastname: Farajollahi
authors.forename: Carla
authors.initials: C
authors.lastname: Nishimura
authors.forename: Khadijeh
authors.initials: K
authors.lastname: Jalalvand
authors.forename: Sanaz
authors.initials: S
authors.lastname: Arzhangi
authors.forename: Kimia
authors.initials: K
authors.lastname: Kahrizi
authors.forename: Richard J H
authors.initials: RJ
authors.lastname: Smith
authors.forename: Hossein
authors.initials: H
authors.lastname: Najmabadi
mesh_terms: D018912:Arabs / Q000235:genetics*; D001382:Azerbaijan / Q000208:ethnology; D016022:Case-Control Studies; D000072259:Connexin 26; D017630:Connexins / Q000235:genetics*; D005260:Female; D005808:Genes, Recessive; D020022:Genetic Predisposition to Disease / Q000453:epidemiology*; D005820:Genetic Testing / Q000379:methods*; D006319:Hearing Loss, Sensorineural / Q000175:diagnosis / Q000208:ethnology* / Q000235:genetics*; D006720:Homozygote; D006801:Humans; D007492:Iran / Q000453:epidemiology; D008297:Male; D009154:Mutation; D010375:Pedigree; D016133:Polymerase Chain Reaction / Q000379:methods; D015995:Prevalence
chemical_list: D017630:Connexins; C000607042:GJB2 protein, human; D000072259:Connexin 26