title: Spectrum and frequency of GJB2 mutations causing deafness in the northwest of Iran.
abstract: OBJECTIVE
  Mutations in GJB2 and GJB6 which comprise DFNB1 locus cause up to half of all cases of the prelingual autosomal recessive non-syndromic hearing loss (ARNSHL) worldwide. This study has intended to assess the spectrum and frequency of GJB2/GJB6 mutations in northwest of Iran.
  
  
  METHODS
  508 Patients with presumed ARNSHL were analyzed by applying ARMS-PCR, SSCP, PCR-RFLP and sequencing assays.
  
  
  RESULTS
  Seventy-five (14.7%) different homozygous and eighty-seven (17.1%) different compound heterozygous genotypes were detected in this cohort. Concerning the GJB2 gene, c.35delG was the most prevalent mutation, accounting for 16.4% of the samples. In addition 29 sequence variations other than c.35delG mutation were distinguished in GJB2; namely, delE120, Ins A 290-291, R143Q, V37I, R32H, Y155X, V27I + T123N, F154F, 167delT, 312del14, 299-300delA, T8M, W24X, E114G + V27I, 235delC, R184P, V153I, S139N, A171T, M163V (unknown mutation), G127V, E147X, R127H, 35insG, R143W, V27I, G160S, E114G and IVS1 + 1G > A. Moreover, the IVS1 + 1G > A was accounted as a second common mutation.
  
  
  CONCLUSIONS
  Overall, the frequency of GJB2 mutations (≥31%) is in agreement with other white population. These findings highlight the importance of the study of GJB2 gene in the diagnosis to provide early treatment and genetic counseling.
authors: Center of Excellence for Biodiversity, Faculty of Natural Sciences, University of Tabriz, Tabriz, Iran; Liver and Gastrointestinal Disease Research Center, Tabriz University of Medical Sciences, Tabriz, Iran. Electronic address: Jabbarpour@tabrizu.ac.ir.
authors: Mortaza J
authors: MJ
authors: Bonyadi
authors: Liver and Gastrointestinal Disease Research Center, Tabriz University of Medical Sciences, Tabriz, Iran. Electronic address: nku.fotouhi86@gmail.com.
authors: Nikou
authors: N
authors: Fotouhi
authors: Institute of Human Genetics, Jena University Hospital, Jena, Germany. Electronic address: mesmaiili@yahoo.com.
authors: Mohsen
authors: M
authors: Esmaeili
mesh_terms: D000483:Alleles; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D000072259:Connexin 26; D017630:Connexins / Q000235:genetics*; D003638:Deafness / Q000453:epidemiology / Q000235:genetics; D005260:Female; D005787:Gene Frequency; D020022:Genetic Predisposition to Disease / Q000453:epidemiology*; D006319:Hearing Loss, Sensorineural / Q000453:epidemiology / Q000235:genetics*; D006801:Humans; D015994:Incidence; D007223:Infant; D007492:Iran / Q000453:epidemiology; D008297:Male; D009154:Mutation / Q000235:genetics*; D016133:Polymerase Chain Reaction / Q000379:methods
chemical_list: D017630:Connexins; C000607042:GJB2 protein, human; D000072259:Connexin 26
keywords: 35delG; ARNSHL; GJB2 gene; Prelingual hearing loss