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- 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.
- Audiological biomarkers of tinnitus in an older Portuguese populationPublication . Haider, Haúla F.; Ribeiro, Diogo; Ribeiro, Sara F.; Trigueiros, Nuno; Caria, Helena; Borrego, Luís; Pinto, Iola; Papoila, Ana L.; Hoare, Derek J.; Paço, JoãoTinnitus is a phantom sound perceived in the absence of external acoustic stimulation. It is described in a variety of ways (e.g., buzzing, ringing, and roaring) and can be a single sound or a combination of different sounds. Our study evaluated associations between audiological parameters and the presence or severity of tinnitus, to improve tinnitus diagnosis, treatment, and prognosis. Our sample included 122 older participants (63 women and 59 men), aged 55–75 years from the Portuguese population, with or without sensory presbycusis and with or without tinnitus. All participants underwent a clinical evaluation through a structured interview, Ear, Nose, and Throat observation, and audiological evaluation (standard and extended audiometry, psychoacoustic tinnitus evaluation, auditory brainstem responses, and distortion product otoacoustic emissions). The Tinnitus Handicap Inventory was used to measure tinnitus symptom severity. Our data confirmed that the odds of developing tinnitus were significantly higher in the presence of noise exposure and hearing loss. Also, participants who had abrupt tinnitus onset and moderate or severe hyperacusis featured higher odds of at least moderate tinnitus. However, it was in the ABR that we obtained the most exciting and promising results, namely, in wave I, which was the common denominator in all findings. The increase in wave I amplitude is a protective factor to the odds of having tinnitus. Concerning the severity of tinnitus, the logistic regression model showed that for each unit of increase in the mean ratio V/I of ABR, the likelihood of having at least moderate tinnitus was 10% higher. Advancing knowledge concerning potential tinnitus audiological biomarkers can be crucial for the adequate diagnosis and treatment of tinnitus.
- Despite reproductive interference, the net outcome of reproductive interactions among spider mite species is not necessarily costlyPublication . Clemente, Salomé; Santos, Inês; Ponce, Rita; Rodrigues, Leonor; Varela, Susana; Magalhães, SaraReproductive interference is considered a strong ecological force, potentially leading to species exclusion. This supposes that the net effect of reproductive interactions is strongly negative for one, or both, of the species involved. Testing this requires a comprehensive analysis of interspecific reproductive interactions, accounting for the order and timing of mating events, and for their effects on either fertility or fecundity. To this aim, we measured reproductive interactions among spider mites, using a focal species, Tetranychus urticae, and an invasive (T. evansi) and a resident (T. ludeni) species, varying the mating sequence and interval, and measuring the effect of such crosses on fecundity and offspring sex ratio (a measure of fertility, as these species are haplodiploid). We found that mating with heterospecifics affected fecundity and sex ratio negatively or positively, depending on the species involved, and on the order and timing of mating events. Overall, the net effect of reproductive interactions was weak despite strong effects of particular events. In natural situations, the outcome of reproductive interactions will thus hinge upon the frequency of each event.
- Differences in the genotype frequencies of genes related to blood pressure regulation: a comparative study between South-West Europe and Peri-equatorial AfricaPublication . Aguiar, Laura; Semente, Ildegário; Ferreira, Joana; Carvalho, Andreia; Silva, Alda P.; Caroça, Cristina; Caria, Helena; Damasceno, Albertino; Laires, Maria J.; Sardinha, Luís; Monteiro, Cristina; Mascarenhas, Mário R.; Faustino, Paula; Inácio, Ângela; Bicho, ManuelBackground: Since the emergence of the genus Homo, hominids have occupied a wide variety of environments, facing different selective pressures. Objectives: The aim this study is to compare genotype frequencies between South-West Europe and Peri-equatorial Africa in genes potentially modulators of blood pressure. Methods: The analyzed sample consisted of 325 individuals from Portugal and 226 individuals from Africa (48 from Mo- zambique and 178 from São Tomé and Príncipe). The following genetic variants were analyzed: intron 4 VNTR in eNOS, rs1050829 in G6PD, -3.7kb α-thalassemic deletion in HBA, rs1800457 in CYB5R3, Hp 1/2 genotype/phenotype in Hp and intron 16 I/D in ACE. Results: Frequencies of genotypes with the 4a allele in eNOS (p<0.001), the G allele in G6PD (p<0.001), the α-3.7 kb in HBA (p <0.001), the C allele in the CYB5R3 (p<0.001) were higher in Peri-equatorial Africa. The Hp 1.1 genotype of Hp has a higher frequency in Peri-equatorial Africa (p=0.002). ACE shows no significant differences. Conclusion: Results show differences in five genetic variants. Conditions of extreme heat and humidity, characteristic of Peri-equatorial Africa, have been associated with increased sodium loss. This study suggests that selected compensatory mechanisms printed in the genome, are nowadays risk factors for hypertension in Peri-equatorial Africa.
- G6PD variants, malaria and sensorineural hearing loss in São Tomé and Príncipe: a case-control studyPublication . Caroça, Cristina; Campelo, Paula; Caria, Helena; Paço, João; Silva, SusanaBackground: São Tomé and Príncipe (STP) is a least developed country (LDC) on Sub-Saharan Africa, in which was detected a high prevalence of sensorineural Hearing Loss (SNHL). HL is a common condition with both genetic and environmental causes, and it greatly impacts on global health. STP population has leading with additional health problems over the years, such as anaemia and malaria infection. The present study aims to identify the correlation between the most prevalent G6PD variants and the high prevalence of HL in STP population. Methods: A sample of 316 individuals collected during Humanitarian Missions in STP, was retrospectively studied in a case-control approach to evaluate the role of G6PD gene variants in individual susceptibility to HL and it correlation with other potential risk factors. Results: The results obtained showed an increased risk for those cases that have reported malaria infection (OR 1.867, CI 95% [1.107-3.48]) in global population. The same effect of increased risk was found after stratification for male gender (OR 3.721 CI 95% [1.631-8.489]). Conclusions: Our results did not allow us to correlate any specific variant of G6PD gene with HL. However, emphasize the hypothetical correlation between malaria infection and the increased risk for HL.
- Genetic evaluation of prelingual hearing impairment: recommendations of an European Network for Genetic Hearing ImpairmentPublication . Jonard, Laurence; Brotto, Davide; Moreno-Palayo, Miguel A.; Castillo, Ignacio del; Kremer, Hannie; Pennings, Ronald; Caria, Helena; Fialho, Graça
- 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.
- Pathophysiology, diagnosis and treatment of somatosensory tinnitus: a scoping reviewPublication . Haider, H. F.; Hoare, D. J.; Costa, R. F.; Potgieter, Iskra; Kikidis, D.; Lapira, A.; Nikitas, C.; Caria, H.; Cunha, N.; Paço, J.
- Phenotypic variability of patients homozygous for the GJB2 mutation 35delG cannot be explained by the influence of one major modifier gene: Influence of modifiers on 35delG/35delG phenotypePublication . Hilgert, Nele; Caria, Helena; Van Camp, GuyHereditary hearing loss (HL) is a very heterogeneous trait, with 46 gene identifications for non-syndromic HL. Mutations in GJB2 cause up to half of all cases of severe-to-profound congenital autosomal recessive non-syndromic HL, with 35delG being the most frequent mutation in Caucasians. Although a genotype-phenotype correlation has been established for most GJB2 genotypes, the HL of 35delG homozygous patients is mild to profound. We hypothesise that this phenotypic variability is at least partly caused by the influence of modifier genes. By performing a whole-genome association (WGA) study on 35delG homozygotes, we sought to identify modifier genes. The association study was performed by comparing the genotypes of mild/moderate cases and profound cases. The first analysis included a pooling-based WGA study of a first set of 255 samples by using both the Illumina 550K and Affymetrix 500K chips. This analysis resulted in a ranking of all analysed single-nucleotide polymorphisms (SNPs) according to their P-values. The top 250 most significantly associated SNPs were genotyped individually in the same sample set. All 192 SNPs that still had significant P-values were genotyped in a second independent set of 297 samples for replication. The significant P-values were replicated in nine SNPs, with combined P-values between 3 x 10(-3) and 1 x 10(-4). This study suggests that the phenotypic variability in 35delG homozygous patients cannot be explained by the effect of one major modifier gene. Significantly associated SNPs may reflect a small modifying effect on the phenotype. Increasing the power of the study will be of greatest importance to confirm these results.
- Prevalência da algaliação sem indicação: um factor de risco evitávelPublication . Caramujo, Natércia; Carvalho, Manuel; Caria, HelenaA Infecção Associada aos Cuidados de Saúde constitui um problema com consequências importantes a nível socio-económico em todo o Mundo. A Infecção do Tracto Urinário é uma das Infecções Associadas aos Cuidados de Saúde com maior importância pela grande repercussão em termos de morbilidade, de impacto pessoal para os doentes e suas familias além do impacto económico para as instituições. A algaliação é reconhecida como o principal factor de risco associado à infecção do tracto urinário. No entanto, a sua utilização é, por vezes, essencial na prestação de cuidados de saúde. A frequência com que os doentes são algaliados e o tempo de algaliação determina o maior ou menor risco de infecção do tracto urinário. Se o doente estiver inapropriadamente algaliado então esse risco é evitável. O objectivo do presente estudo foi determinar a frequência da algaliação evitável num Departamento de Medicina, o que envolveu a análise de todos os doentes internados para determinar a presença de algaliação, em dois dias diferentes, e ainda a posterior consulta dos processos clínicos dos doentes algaliados para identificar os casos onde tinham surgido infecções do tracto urinário. Dos 160 doentes internados no período do estudo, 20% tinham catéter vesical. A indicação da algaliação foi na sua maioria (84,4%) médica. Nos indivíduos estudados, foi observado que 25% não tinham indicação apropriada para estarem algaliados naquele dia, verificando-se como justificações para a permanência da algália a gestão da incontinência (6,2%) e a ausência de indicação para a sua remoção (18,8%). Verificámos que doze dos indivíduos da amostra (37,5%) desenvolveram Infecção do Tracto Urinário e que cinco desses casos não tinham indicação apropriada para estarem algaliados. Concluiu-se que cinco casos de Infecção do Tracto Urinário eram potencialmente evitáveis. Este número corresponde a 41,7% do total das Infecções do Tracto Urinário identificadas. Este é um dado relevante se considerarmos o objectivo de melhorar continuamente a prestação de cuidados, bem como todos os custos associados ao tratamento de infecções do tracto urinário.