Spectrum and frequency of GJB2 mutations in a cohort of 264 Portuguese nonsyndromic sensorineural hearing loss patients

Tiago Daniel Matos, Helena Simões-Teixeira, Helena Caria, Ana Cláudia Gonçalves, Joana Chora, Maria Do Céu Correia, Carla Moura, Helena Rosa, Luísa Monteiro, Assunção O'Neill, Óscar Dias, Mário Andrea, Graça Fialho

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16 Citations (Scopus)


Objective: To assess the spectrum and prevalence of mutations in the GJB2 gene in Portuguese nonsyndromic sensorineural hearing loss (NSSHL) patients. Design: Sequencing of the coding region, basal promoter, exon 1, and donor splice site of the GJB2 gene; screening for the presence of the two common GJB6 deletions. Study sample: A cohort of 264 Portuguese NSSHL patients. Results: At least one out of 21 different GJB2 variants was identified in 80 (30.2%) of the 264 patients analysed. Two mutant alleles were found in 53 (20%) of these probands, of which 83% (44/53) harboured at least one c.35delG allele. Twenty-seven (10.2%) of the probands harboured only one mutant allele. Subsequent analysis revealed that the GJB6 deletion del(GJB6-D13S1854) was present in at least 7.4% (2/27) of the patients carrying only one mutant GJB2 allele. Overall, one in five (55/264) of the patients were diagnosed as having DFNB1-related NSSHL, of which the vast majority (53/55) harboured only GJB2 mutations. Conclusions: This study provides clear demonstration that mutations in the GJB2 gene are an important cause of NSSHL in Portugal, thus representing a valuable indicator as regards therapeutical and rehabilitation options, as well as genetic counseling of these patients and their families.

Original languageEnglish
Pages (from-to)466-471
Number of pages6
JournalInternational Journal Of Audiology
Issue number7
Publication statusPublished - 1 Jul 2013


  • Connexin 26
  • Deafness
  • DFNB1
  • Genetic
  • GJB2
  • GJB6
  • Hearing loss
  • Hereditary
  • Mutation


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