Spectrum and frequency of gjb2 mutations in a cohort of 264 portuguese nonsyndromic sensorineural hearing loss patients

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.

URI

http://hdl.handle.net/10400.26/21229

Citation

Matos, T.D., Simões-Teixeira, H., Caria, H., Gonçalves, A.C., Chora, J., Correia, M.C. …Fialho, G.(2013). Spectrum and frequency of gjb2 mutations in a cohort of 264 portuguese nonsyndromic sensorineural hearing loss patients. International Journal of Audiology, 52 (7), p.p. 466-71. doi: 10.3109/14992027.2013.783719