Autor(es):
Matos, T ; Simões-Teixeira, H ; Caria, H ; Gonçalves, AC ; Chora, J ; Correia, MC ; Moura, C ; Rosa, H ; Monteiro, L ; O'Neill, A ; Dias, O ; Andrea, M ; Fialho, G
Data: 2013
Identificador Persistente: http://hdl.handle.net/10400.17/2497
Origem: Repositório do Centro Hospitalar de Lisboa Central, EPE
Assunto(s): Audiometry; Connexins; DNA Mutational Analysis; Exons; Gene Frequency; Genetic Predisposition to Disease; Hearing Loss, Sensorineural; Humans; Otoscopy; Phenotype; Portugal; RNA Splice Sites; Severity of Illness Index; Mutation; HDE ORL
Descrição
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.
