Browsing by Author "O'Neill, A."
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- Age-related hearing loss: is this a preventable condition?Publication . Aparício, M.; Matos, T. M.; Arguello, Patricia; Antunes, M.; O'Neill, A.; Escada, P.; Caria, Helena
- ARHL and Tinnitus in Portuguese Population: what we can hear from a sample of elderly individuals.Publication . Flook, M.; Lopes, S.; Aparicio, M.; Santos, R.; Andrade, C.; Andrade, S.; Martins, J.; O'Neill, A.; Escada, P.; Argüello, Patricia; Alcântara, P.; O'Neill, J.; Villaverde Cabral, M.; Antunes, M.; Matos, T.; Fialho, G.; Caria, H.
- Assessing Noncoding Sequence Variants of GJB2 for Hearing Loss Association.Publication . Matos, T. D.; Simões-Teixeira, H.; Caria, Helena; Cascão, R.; Rosa, H.; O'Neill, A.; Dias, O.; Andrea, M.E.; Kelsell, D. P.; Fialho, G.Involvement of GJB2 noncoding regions in hearing loss (HL) has not been extensively investigated. However, three noncoding mutations, c.-259C>T, c.-23G>T, and c.-23+1G>A, were reported. Also, c.-684 -675del, of uncertain pathogenicity, was found upstream of the basal promoter. We performed a detailed analysis of GJB2 noncoding regions in Portuguese HL patients (previously screened for GJB2 coding mutations and the common GJB6 deletions) and in control subjects, by sequencing the basal promoter and flanking upstream region, exon 1, and 3’UTR. All individuals were genotyped for c.-684 -675del and 14 SNPs. Novel variants (c.-731C>T, c.-26G>T, c.∗45G>A, and c.∗985A>T) were found in controls. A hearing individual homozygous for c.-684 - 675del was for the first time identified, supporting the nonpathogenicity of this deletion. Our data indicate linkage disequilibrium (LD) between SNPs rs55704559 (c.∗168A>G) and rs5030700 (c.∗931C>T) and suggest the association of c.[∗168G;∗931T] allele with HL. The c.∗168A>G change, predicted to alter mRNA folding, might be involved in HL.
- Epidemiology, genetics and social impact of arhl: a portuguese examplePublication . Flook, M.; Lopes, S.; Alves, L.; Aparício, M.; Martins, J. H.; Silva, E.; Murta, A.; Andrade, S.; Andrade, C.; O'Neill, A.; Matos, T.; Antunes, M.; Escada, P.; Alcântara, P.; O'Neill, J.; Villaverde Cabral, M.; Fialho, J.; Caria, H.
- Gender effect, quality of life and genetic biomarkers in a Portuguese sample with ARHL with or without tinnitusPublication . Haider, H.; Matskul, G.; Ribeiro, D.; Ribeiro, S.; Escada, P.; O'Neill, A.; Fialho, G.; Paço, J.; Caria, Helena
- A Novel p.Leu213X Mutation in GJB2 Gene in a Portuguese FamilyPublication . Gonçalves, A. C.; Chora, J.; Matos, T. D.; O'Neill, A.; Escada, P.; Fialho, G.; Caria, H.
- Spectrum and frequency of gjb2 mutations in a cohort of 264 portuguese nonsyndromic sensorineural hearing loss patientsPublication . Matos, T. D.; Simões-Teixeira, H.; Caria, Helena; Gonçalves, A. C.; Chora, J.; Correia, M. C.; Moura, C.; Rosa, H.; Monteiro, L.; O'Neill, A.; Dias, O.; Andrea, M.; Fialho, G.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.