Spectrum of GJB2 (Cx26) gene mutations in Iranian Azeri patients with nonsyndromic autosomal recessive hearing loss

Int J Pediatr Otorhinolaryngol. 2012 Feb;76(2):268-71. doi: 10.1016/j.ijporl.2011.11.019. Epub 2011 Dec 14.


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).

Result: 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.

Conclusion: Our results suggest that c.35delG mutation in the GJB2 gene is the most important cause of GJB2 related deafness in Iranian Azeri population.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Arabs / genetics*
  • Azerbaijan / ethnology
  • Case-Control Studies
  • Connexin 26
  • Connexins / genetics*
  • Female
  • Genes, Recessive
  • Genetic Predisposition to Disease / epidemiology*
  • Genetic Testing / methods*
  • Hearing Loss, Sensorineural / diagnosis
  • Hearing Loss, Sensorineural / ethnology*
  • Hearing Loss, Sensorineural / genetics*
  • Homozygote
  • Humans
  • Iran / epidemiology
  • Male
  • Mutation*
  • Pedigree
  • Polymerase Chain Reaction / methods
  • Prevalence


  • Connexins
  • GJB2 protein, human
  • Connexin 26

Supplementary concepts

  • Nonsyndromic sensorineural hearing loss