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1.
J Med Genet ; 2020 Jul 06.
Artigo em Inglês | MEDLINE | ID: mdl-32631815

RESUMO

BACKGROUND: Hearing loss is one of the most prevalent disabilities worldwide, and has a significant impact on quality of life. The adult-onset type of the condition is highly heritable but the genetic causes are largely unknown, which is in contrast to childhood-onset hearing loss. METHODS: Family and cohort studies included exome sequencing and characterisation of the hearing phenotype. Ex vivo protein expression addressed the functional effect of a DNA variant. RESULTS: An in-frame deletion of 12 nucleotides in RIPOR2 was identified as a highly penetrant cause of adult-onset progressive hearing loss that segregated as an autosomal dominant trait in 12 families from the Netherlands. Hearing loss associated with the deletion in 63 subjects displayed variable audiometric characteristics and an average (SD) age of onset of 30.6 (14.9) years (range 0-70 years). A functional effect of the RIPOR2 variant was demonstrated by aberrant localisation of the mutant RIPOR2 in the stereocilia of cochlear hair cells and failure to rescue morphological defects in RIPOR2-deficient hair cells, in contrast to the wild-type protein. Strikingly, the RIPOR2 variant is present in 18 of 22 952 individuals not selected for hearing loss in the Southeast Netherlands. CONCLUSION: Collectively, the presented data demonstrate that an inherited form of adult-onset hearing loss is relatively common, with potentially thousands of individuals at risk in the Netherlands and beyond, which makes it an attractive target for developing a (genetic) therapy.

2.
Ophthalmology ; 123(5): 1151-60, 2016 May.
Artigo em Inglês | MEDLINE | ID: mdl-26927203

RESUMO

PURPOSE: USH2A mutations are an important cause of retinitis pigmentosa (RP) with or without congenital sensorineural hearing impairment. We studied genotype-phenotype correlations and compared visual prognosis in Usher syndrome type IIa and nonsyndromic RP. DESIGN: Clinic-based, longitudinal, multicenter study. PARTICIPANTS: Consecutive patients with Usher syndrome type IIa (n = 152) and nonsyndromic RP (n = 73) resulting from USH2A mutations from ophthalmogenetic clinics in the Netherlands and Belgium. METHODS: Data on clinical characteristics, visual acuity, visual field measurements, retinal imaging, and electrophysiologic features were extracted from medical charts over a mean follow-up of 9 years. Cumulative lifetime risks of low vision and blindness were estimated using Kaplan-Meier survival analysis. MAIN OUTCOME MEASURES: Low vision and blindness. RESULTS: Participant groups had similar distributions of gender (48% vs. 45% males in Usher syndrome type IIa vs. nonsydromic RP; P = 0.8), ethnicity (97% vs. 99% European; P = 0.3), and median follow-up time (6.5 years vs. 3 years; P = 0.3). Usher syndrome type IIa patients demonstrated symptoms at a younger age (median age, 15 years vs. 25 years; P < 0.001), were diagnosed earlier (median age, 26 years vs. 36.5 years; P < 0.001), and became visually impaired 13 years earlier (median age, 41 years vs. 54 years; P < 0.001) based on VF and 18 years earlier based on VA (median age, 54 years vs. 72 years; P < 0.001) than nonsyndromic RP patients. The presence of 2 truncating mutations in USH2A was associated mostly with the syndromic phenotype, whereas other combinations were present in both groups. We found novel variants in Usher syndrome type IIa (25%) and nonsyndromic RP (19%): 29 missense mutations, 10 indels, 14 nonsense mutations, 9 frameshift mutations, and 5 splice-site mutations. CONCLUSIONS: Most patients with USH2A-associated RP have severe visual impairment by age 50. However, those with Usher syndrome type IIa have an earlier decline of visual function and a higher cumulative risk of visual impairment than those without nonsyndromic RP. Complete loss of function of the USH2A protein predisposes to Usher syndrome type IIa, but remnant protein function can lead to RP with or without hearing loss.


Assuntos
Proteínas da Matriz Extracelular/genética , Retinose Pigmentar/genética , Síndromes de Usher/genética , Acuidade Visual/fisiologia , Adolescente , Adulto , Idoso , Cegueira/fisiopatologia , Análise Mutacional de DNA , Feminino , Seguimentos , Estudos de Associação Genética , Humanos , Masculino , Pessoa de Meia-Idade , Mutação , Prognóstico , Retinose Pigmentar/fisiopatologia , Síndromes de Usher/fisiopatologia , Baixa Visão/fisiopatologia , Campos Visuais/fisiologia
3.
Nat Genet ; 38(4): 414-7, 2006 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-16501574

RESUMO

Lacrimo-auriculo-dento-digital (LADD) syndrome is characterized by lacrimal duct aplasia, malformed ears and deafness, small teeth and digital anomalies. We identified heterozygous mutations in the tyrosine kinase domains of the genes encoding fibroblast growth factor receptors 2 and 3 (FGFR2, FGFR3) in LADD families, and in one further LADD family, we detected a mutation in the gene encoding fibroblast growth factor 10 (FGF10), a known FGFR ligand. These findings increase the spectrum of anomalies associated with abnormal FGF signaling.


Assuntos
Anormalidades Múltiplas/genética , Fatores de Crescimento de Fibroblastos/metabolismo , Mutação , Transdução de Sinais , Feminino , Humanos , Masculino , Linhagem , Receptor Tipo 2 de Fator de Crescimento de Fibroblastos/genética , Receptor Tipo 3 de Fator de Crescimento de Fibroblastos/genética , Síndrome
4.
Am J Hum Genet ; 89(6): 813-9, 2011 Dec 09.
Artigo em Inglês | MEDLINE | ID: mdl-22152683

RESUMO

Congenital aural atresia (CAA) can occur as an isolated congenital malformation or in the context of a number of monogenic and chromosomal syndromes. CAA is frequently seen in individuals with an 18q deletion, which is characterized by intellectual disability, reduced white-matter myelination, foot deformities, and distinctive facial features. Previous work has indicated that a critical region for CAA is located in 18q22.3. We studied four individuals (from two families) with CAA and other features suggestive of an 18q deletion, and we detected overlapping microdeletions in 18q22.3 in both families. The minimal region of deletion overlap (72.9-73.4 Mb) contained only one known gene, TSHZ1, which was recently shown to be important for murine middle-ear development. Sequence analysis of the coding exons in TSHZ1 in a cohort of 11 individuals with isolated, nonsyndromic bilateral CAA revealed two mutations, c.723G>A (p.Trp241X) and c.946_947delinsA (p.Pro316ThrfsX16), and both mutations predicted a loss of function. Together, these results demonstrate that hemizygosity of TSHZ1 leads to congenital aural atresia as a result of haploinsufficiency.


Assuntos
Perda Auditiva/genética , Proteínas de Homeodomínio/genética , Anormalidades Múltiplas/genética , Adulto , Criança , Pré-Escolar , Deleção Cromossômica , Cromossomos Humanos Par 18 , Meato Acústico Externo/anormalidades , Feminino , Pé Chato , Deformidades Congênitas do Pé/diagnóstico por imagem , Deformidades Congênitas do Pé/genética , Estudos de Associação Genética , Haploinsuficiência , Perda Auditiva/diagnóstico , Humanos , Lactente , Masculino , Linhagem , Gravidez , Proteínas Repressoras , Tomografia Computadorizada por Raios X , Ultrassonografia Pré-Natal
5.
Am J Hum Genet ; 86(4): 604-10, 2010 Apr 09.
Artigo em Inglês | MEDLINE | ID: mdl-20346435

RESUMO

We identified overlapping homozygous regions within the DFNB84 locus in a nonconsanguineous Dutch family and a consanguineous Moroccan family with sensorineural autosomal-recessive nonsyndromic hearing impairment (arNSHI). The critical region of 3.17 Mb harbored the PTPRQ gene and mouse models with homozygous mutations in the orthologous gene display severe hearing loss. We show that the human PTPRQ gene was not completely annotated and that additional, alternatively spliced exons are present at the 5' end of the gene. Different PTPRQ isoforms are encoded with a varying number of fibronectin type 3 (FN3) domains, a transmembrane domain, and a phosphatase domain. Sequence analysis of the PTPRQ gene in members of the families revealed a nonsense mutation in the Dutch family and a missense mutation in the Moroccan family. The missense mutation is located in one of the FN3 domains. The nonsense mutation results in a truncated protein with only a small number of FN3 domains and no transmembrane or phosphatase domain. Hearing loss in the patients with PTPRQ mutations is likely to be congenital and moderate to profound and most severe in the family with the nonsense mutation. Progression of the hearing loss was observed in both families. The hearing loss is accompanied by vestibular dysfunction in all affected individuals. Although we show that PTPRQ is expressed in many tissues, no symptoms other than deafness were observed in the patients.


Assuntos
Códon sem Sentido/genética , Genes Recessivos , Perda Auditiva/genética , Perda Auditiva/patologia , Proteínas Tirosina Fosfatases Classe 3 Semelhantes a Receptores/genética , Doenças Vestibulares/genética , Regiões 5' não Traduzidas/genética , Sequência de Aminoácidos , Estudos de Casos e Controles , Estudos de Coortes , Feminino , Homozigoto , Humanos , Masculino , Pessoa de Meia-Idade , Dados de Sequência Molecular , Linhagem , Polimorfismo de Nucleotídeo Único/genética , Homologia de Sequência de Aminoácidos , Doenças Vestibulares/fisiopatologia , Testes de Função Vestibular
6.
Am J Hum Genet ; 86(2): 138-47, 2010 Feb 12.
Artigo em Inglês | MEDLINE | ID: mdl-20137778

RESUMO

We identified overlapping homozygous regions within the DFNB25 locus in two Dutch and ten Pakistani families with sensorineural autosomal-recessive nonsyndromic hearing impairment (arNSHI). Only one of the families, W98-053, was not consanguineous, and its sibship pointed toward a reduced critical region of 0.9 Mb. This region contained the GRXCR1 gene, and the orthologous mouse gene was described to be mutated in the pirouette (pi) mutant with resulting hearing loss and circling behavior. Sequence analysis of the GRXCR1 gene in hearing-impaired family members revealed splice-site mutations in two Dutch families and a missense and nonsense mutation, respectively, in two Pakistani families. The splice-site mutations are predicted to cause frameshifts and premature stop codons. In family W98-053, this could be confirmed by cDNA analysis. GRXCR1 is predicted to contain a GRX-like domain. GRX domains are involved in reversible S-glutathionylation of proteins and thereby in the modulation of activity and/or localization of these proteins. The missense mutation is located in this domain, whereas the nonsense and splice-site mutations may result in complete or partial absence of the GRX-like domain or of the complete protein. Hearing loss in patients with GRXCR1 mutations is congenital and is moderate to profound. Progression of the hearing loss was observed in family W98-053. Vestibular dysfunction was observed in some but not all affected individuals. Quantitative analysis of GRXCR1 transcripts in fetal and adult human tissues revealed a preferential expression of the gene in fetal cochlea, which may explain the nonsyndromic nature of the hearing impairment.


Assuntos
Mapeamento Cromossômico , Genes Recessivos/genética , Glutarredoxinas/genética , Perda Auditiva/genética , Homozigoto , Mutação/genética , Sequência de Aminoácidos , Sequência de Bases , Cóclea/metabolismo , Cóclea/patologia , Análise Mutacional de DNA , Família , Perfilação da Expressão Gênica , Regulação da Expressão Gênica , Loci Gênicos/genética , Glutarredoxinas/química , Perda Auditiva/fisiopatologia , Humanos , Escore Lod , Dados de Sequência Molecular , Especificidade de Órgãos/genética , Splicing de RNA/genética , Alinhamento de Sequência , Vestíbulo do Labirinto/fisiopatologia
7.
Ear Hear ; 34(6): 806-8, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23698625

RESUMO

OBJECTIVES: The aim of the study was to investigate whether children with bilateral conductive hearing loss benefit from their second device (i.e., the bilateral bone conduction device [BCD]). DESIGN: Speech recognition in noise was assessed in 10 children fitted with bilateral BCDs during childhood. Speech recognition was measured in 2 conditions with both BCDs active. Spatial resolution was tested with the Minimum Audible Angle test in the bilateral and monaural listening conditions. RESULTS: Children demonstrated an improvement in speech recognition when speech was presented from the front and noise was presented from the right-hand side as compared with both speech and noise being presented from the front. The minimum audible angle decreased from 57° in the best monaural condition to 13° in the bilateral condition. CONCLUSIONS: The audiological outcomes demonstrate the advantage of bilateral BCD fitting in children with bilateral conductive hearing loss.


Assuntos
Condução Óssea/fisiologia , Implantes Cocleares , Perda Auditiva Bilateral/reabilitação , Perda Auditiva Condutiva/reabilitação , Ruído , Localização de Som/fisiologia , Percepção da Fala/fisiologia , Adolescente , Criança , Pré-Escolar , Feminino , Humanos , Masculino , Testes de Discriminação da Fala/métodos
8.
Eur Arch Otorhinolaryngol ; 270(4): 1285-91, 2013 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-22903754

RESUMO

The objective of this study is to determine the benefits of bone-anchored hearing aid (Baha) contralateral routing of signal (CROS) in the older adult population with single-sided deafness. Five questionnaires [general usage questionnaire, Glasgow benefit inventory (GBI), Abbreviated profile of hearing aid benefit (APHAB), Nijmegen cochlear implant questionnaire and the hearing handicap inventory for the elderly-screening version (HHIE-S)] were used to evaluate Baha use. Consecutive patients over 60 years of age with SSD fitted with a Baha CROS between April 1990 and April 2007 not using a conventional hearing aid in the better-hearing ear were identified. Nine out of 11 patients (82 %) were still using their Baha CROS, and 7 of the 11 patients (64 %) were still satisfied. The patients experienced no to little problems with handling and cleaning of the device. The GBI scores show good benefit in domains total (14 ± 11) and general (19 ± 17). The APHAB shows that, overall, 3 out of the 11 patients (27 %) experienced significant benefit, while all others experienced no significant benefit and no drawbacks. The HHIE-S shows that the patients experienced severe (18 %), mild to moderate (46 %) or no handicap (36 %) when using the Baha CROS. In conclusion, the benefit of a Baha CROS for elderly patients with SSD is evident in the majority of patients.


Assuntos
Auxiliares de Audição , Perda Auditiva Unilateral/reabilitação , Âncoras de Sutura , Idoso , Idoso de 80 Anos ou mais , Feminino , Seguimentos , Auxiliares de Audição/psicologia , Perda Auditiva Unilateral/psicologia , Humanos , Masculino , Pessoa de Meia-Idade , Satisfação do Paciente , Qualidade de Vida/psicologia , Inquéritos e Questionários
9.
Am J Hum Genet ; 84(3): 328-38, 2009 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-19230858

RESUMO

Otosclerosis is a common form of progressive hearing loss, characterized by abnormal bone remodeling in the otic capsule. The etiology of the disease is largely unknown, and both environmental and genetic factors have been implicated. To identify genetic factors involved in otosclerosis, we used a case-control discovery group to complete a genome-wide association (GWA) study with 555,000 single-nucleotide polymorphisms (SNPs), utilizing pooled DNA samples. By individual genotyping of the top 250 SNPs in a stepwise strategy, we were able to identify two highly associated SNPs that replicated in two additional independent populations. We then genotyped 79 tagSNPs to fine map the two genomic regions defined by the associated SNPs. The region with the strongest association signal, p(combined) = 6.23 x 10(-10), is on chromosome 7q22.1 and spans intron 1 to intron 4 of reelin (RELN), a gene known for its role in neuronal migration. Evidence for allelic heterogeneity was found in this region. Consistent with the GWA data, expression of RELN was confirmed in the inner ear and in stapes footplate specimens. In conclusion, we provide evidence that implicates RELN in the pathogenesis of otosclerosis.


Assuntos
Moléculas de Adesão Celular Neuronais/genética , Proteínas da Matriz Extracelular/genética , Genoma Humano , Proteínas do Tecido Nervoso/genética , Otosclerose/genética , Serina Endopeptidases/genética , Estudos de Casos e Controles , Moléculas de Adesão Celular Neuronais/biossíntese , Orelha Interna/metabolismo , Proteínas da Matriz Extracelular/biossíntese , Feminino , Estudo de Associação Genômica Ampla , Humanos , Masculino , Proteínas do Tecido Nervoso/biossíntese , Otosclerose/metabolismo , Polimorfismo de Nucleotídeo Único , Proteína Reelina , Serina Endopeptidases/biossíntese
10.
Audiol Neurootol ; 17(3): 198-206, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-22399015

RESUMO

Intraoperative findings of stapes surgery in 34 ears from 22 patients with genetically confirmed osteogenesis imperfecta (OI) are reported, as well as the audiometric results after the longest postoperative follow-up published to date. Twenty-nine out of 34 ears underwent primary stapes surgery and 5 ears revision surgery. Postoperative audiometric follow-up ranged from 6 months to 37 years. Stapes footplates were fixed in all ears. Additionally, footplates were thickened or fragile, stapes crura atrophic or fractured, and middle ear mucosae thickened or hypervascularized. Short-term postoperative audiometry revealed improved hearing and reduced air-bone gaps in 28/29 primary operated ears and in all revision cases. In the 22 ears with long-term postoperative follow-up (mean duration: 16 years), hearing gain was still significant at the latest audiometric evaluation. Independently of the patients being diagnosed with OI type I or IV and independently of the underlying OI genotype, beneficial results are obtained in the majority of OI patients undergoing primary or revision stapes surgery for reduction of conductive hearing loss components caused by stapes footplate fixation. Despite the progressive course of the concomitant sensorineural component, hearing gain remains beneficial over several decades.


Assuntos
Perda Auditiva Condutiva/cirurgia , Osteogênese Imperfeita/cirurgia , Cirurgia do Estribo , Adolescente , Adulto , Idoso , Audiometria de Tons Puros , Condução Óssea , Feminino , Perda Auditiva Condutiva/etiologia , Humanos , Masculino , Pessoa de Meia-Idade , Prótese Ossicular , Osteogênese Imperfeita/complicações , Estudos Retrospectivos , Resultado do Tratamento
11.
Audiol Neurootol ; 17(4): 219-27, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-22487897

RESUMO

The Nathalie syndrome (OMIM 255990) comprises a combination of features that do not resemble any other known syndrome and is as such an independent, rare entity. It is characterized by sensorineural hearing impairment, juvenile cataract, spinal muscular atrophy, skeletal abnormalities, retardation of growth, underdeveloped secondary gender characteristics and cardiomyopathy. Worldwide, only one family with this syndrome is known. An update of the clinical follow-up in this family and the results of autopsy are given. Audiometry showed a downsloping configuration that corresponded to the findings at histopathological examination of the cochlea: a diffuse atrophy of the organ of Corti, severe and diffuse atrophy of the stria vascularis and moderate loss of cochlear neurons in all turns. Another new striking feature is that individuals with the Nathalie syndrome have a shortened life expectancy with a risk of sudden death or death from heart failure resulting from (dilated) cardiomyopathy.


Assuntos
Catarata/patologia , Cóclea/patologia , Surdez/patologia , Transtornos do Crescimento/patologia , Perda Auditiva Neurossensorial/patologia , Atrofia Muscular/patologia , Neurônios/patologia , Osteocondrite/patologia , Osso Temporal/patologia , Adolescente , Adulto , Atrofia , Audiometria , Catarata/fisiopatologia , Cóclea/fisiopatologia , Surdez/fisiopatologia , Feminino , Seguimentos , Transtornos do Crescimento/fisiopatologia , Perda Auditiva Neurossensorial/fisiopatologia , Humanos , Masculino , Atrofia Muscular/fisiopatologia , Neurônios/fisiologia , Órgão Espiral/patologia , Órgão Espiral/fisiopatologia , Osteocondrite/fisiopatologia , Linhagem , Estria Vascular/patologia , Estria Vascular/fisiologia , Osso Temporal/fisiopatologia
12.
Ann Otol Rhinol Laryngol ; 121(4): 275-81, 2012 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-22606932

RESUMO

OBJECTIVES: We describe the audiometric results following surgery in a consecutive series of patients with a congenital ossicular middle ear disorder that was associated with a mobile stapes footplate. METHODS: We performed a retrospective analysis of patient charts from a tertiary referral center. A total of 23 patients (23 ears) underwent exploratory tympanotomy and ossicular reconstruction between 1986 and 2001. The main outcome measure was the audiometric results. RESULTS: Overall, we observed a mean gain in air conduction pure tone average of 17 dB (from 47 dB to 30 dB), a sensorineural deterioration of 3 dB, and a mean postoperative air-bone gap of 19 dB (mean preoperative air-bone gap of 38 dB). The air-bone gap closure was 20 dB or less in 15 of the 23 cases (65%), in agreement with the few results reported in the literature. Moreover, the audiometric results remained stable. In the syndromic group, the mean gain in air conduction was only 13 dB, which was worse than that observed for the nonsyndromic ears. CONCLUSIONS: Surgery for congenital ossicular chain anomalies with a concomitant mobile stapes footplate provides positive audiometric outcomes. Most ears had some sensorineural impairment (10 to 20 dB), which influenced the final hearing level attained after surgery. Preoperative assessment is mandatory to search for syndromal diagnoses, which might be important for patient counseling and prognosis.


Assuntos
Ossículos da Orelha/anormalidades , Ossículos da Orelha/cirurgia , Mobilização do Estribo , Estribo/anormalidades , Adolescente , Adulto , Audiometria de Tons Puros , Limiar Auditivo , Condução Óssea , Criança , Feminino , Perda Auditiva Neurossensorial/cirurgia , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Adulto Jovem
13.
Hum Mol Genet ; 18(1): 51-64, 2009 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-18826961

RESUMO

Usher syndrome (USH) and Leber congenital amaurosis (LCA) are autosomal recessive disorders resulting in syndromic and non-syndromic forms of blindness. In order to gain insight into the pathogenic mechanisms underlying retinal degeneration, we searched for interacting proteins of USH2A isoform B (USH2A(isoB)) and the LCA5-encoded protein lebercilin. We identified a novel isoform of the centrosomal ninein-like protein, hereby named Nlp isoform B (Nlp(isoB)), as a common interactor. Although we identified the capacity of this protein to bind calcium with one of its three EF-hand domains, the interacton with USH2A(isoB) did not depend on this. Upon expression in ARPE-19 cells, recombinant Nlp(isoB), lebercilin and USH2A(isoB) were all found to co-localize at the centrosomes. Staining of retinal sections with specific antibodies against all three proteins revealed their co-localization at the basal bodies of the photoreceptor-connecting cilia. Based on this subcellular localization and the nature of their previously identified binding partners, we hypothesize that the pathogenic mechanisms for LCA and USH show significant overlap and involve defects in ciliogenesis, cilia maintenance and intraflagellar and/or microtubule-based transport. The direct association of Nlp(isoB) with USH2A(isoB) and lebercilin indicates that Nlp can be considered as a novel candidate gene for USH, LCA and allied retinal ciliopathies.


Assuntos
Proteínas Associadas aos Microtúbulos/metabolismo , Proteínas Nucleares/metabolismo , Atrofia Óptica Hereditária de Leber/metabolismo , Síndromes de Usher/metabolismo , Sequência de Aminoácidos , Animais , Linhagem Celular , Proteínas da Matriz Extracelular/genética , Proteínas da Matriz Extracelular/metabolismo , Proteínas do Olho/genética , Proteínas do Olho/metabolismo , Humanos , Técnicas In Vitro , Camundongos , Camundongos Endogâmicos C57BL , Proteínas Associadas aos Microtúbulos/química , Proteínas Associadas aos Microtúbulos/genética , Dados de Sequência Molecular , Proteínas Nucleares/química , Proteínas Nucleares/genética , Atrofia Óptica Hereditária de Leber/genética , Células Fotorreceptoras/metabolismo , Ligação Proteica , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , Ratos , Ratos Wistar , Retina/metabolismo , Alinhamento de Sequência , Técnicas do Sistema de Duplo-Híbrido , Síndromes de Usher/genética
14.
Hum Mol Genet ; 18(4): 785-96, 2009 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-19047183

RESUMO

Age-related hearing impairment (ARHI), or presbycusis, is the most prevalent sensory impairment in the elderly. ARHI is a complex disease caused by an interaction between environmental and genetic factors. Here we describe the results of the first whole genome association study for ARHI. The study was performed using 846 cases and 846 controls selected from 3434 individuals collected by eight centers in six European countries. DNA pools for cases and controls were allelotyped on the Affymetrix 500K GeneChip for each center separately. The 252 top-ranked single nucleotide polymorphisms (SNPs) identified in a non-Finnish European sample group (1332 samples) and the 177 top-ranked SNPs from a Finnish sample group (360 samples) were confirmed using individual genotyping. Subsequently, the 23 most interesting SNPs were individually genotyped in an independent European replication group (138 samples). This resulted in the identification of a highly significant and replicated SNP located in GRM7, the gene encoding metabotropic glutamate receptor type 7. Also in the Finnish sample group, two GRM7 SNPs were significant, albeit in a different region of the gene. As the Finnish are genetically distinct from the rest of the European population, this may be due to allelic heterogeneity. We performed histochemical studies in human and mouse and showed that mGluR7 is expressed in hair cells and in spiral ganglion cells of the inner ear. Together these data indicate that common alleles of GRM7 contribute to an individual's risk of developing ARHI, possibly through a mechanism of altered susceptibility to glutamate excitotoxicity.


Assuntos
Predisposição Genética para Doença , Presbiacusia/genética , Receptores de Ácido Caínico/genética , Fatores Etários , Idoso , Animais , Estudos de Casos e Controles , Orelha Interna/metabolismo , Feminino , Estudo de Associação Genômica Ampla , Humanos , Masculino , Camundongos , Pessoa de Meia-Idade , Polimorfismo de Nucleotídeo Único , Presbiacusia/metabolismo , Receptores de Ácido Caínico/metabolismo , População Branca/genética , Receptor de GluK3 Cainato
15.
Am J Hum Genet ; 83(3): 401-7, 2008 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-18760390

RESUMO

Age-related hearing impairment (ARHI), or presbycusis, is a very common multifactorial disorder. Despite the knowledge that genetics play an important role in the etiology of human ARHI as revealed by heritability studies, to date, its precise genetic determinants remain elusive. Here we report the results of a cross-sectional family-based genetic study employing audiometric data. By using principal component analysis, we were able to reduce the dimensionality of this multivariate phenotype while capturing most of the variation and retaining biologically important features of the audiograms. We conducted a genome-wide association as well as a linkage scan with high-density SNP microarrays. Because of the presence of genetic population substructure, association testing was stratified after which evidence was combined by meta-analysis. No association signals reaching genome-wide significance were detected. Linkage analysis identified a linkage peak on 8q24.13-q24.22 for a trait correlated to audiogram shape. The signal reached genome-wide significance, as assessed by simulations. This finding represents the first locus for an ARHI trait.


Assuntos
Envelhecimento/genética , Cromossomos Humanos Par 8/genética , Ligação Genética , Genoma Humano , Polimorfismo de Nucleotídeo Único , Presbiacusia/genética , Idoso , Estudos Transversais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Presbiacusia/fisiopatologia , Análise de Componente Principal , Locos de Características Quantitativas
16.
Am J Hum Genet ; 82(1): 125-38, 2008 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-18179891

RESUMO

In a large consanguineous family of Turkish origin, genome-wide homozygosity mapping revealed a locus for recessive nonsyndromic hearing impairment on chromosome 14q24.3-q34.12. Fine mapping with microsatellite markers defined the critical linkage interval to a 18.7 cM region flanked by markers D14S53 and D14S1015. This region partially overlapped with the DFNB35 locus. Mutation analysis of ESRRB, a candidate gene in the overlapping region, revealed a homozygous 7 bp duplication in exon 8 in all affected individuals. This duplication results in a frame shift and premature stop codon. Sequence analysis of the ESRRB gene in the affected individuals of the original DFNB35 family and in three other DFNB35-linked consanguineous families from Pakistan revealed four missense mutations. ESRRB encodes the estrogen-related receptor beta protein, and one of the substitutions (p.A110V) is located in the DNA-binding domain of ESRRB, whereas the other three are substitutions (p.L320P, p.V342L, and p.L347P) located within the ligand-binding domain. Molecular modeling of this nuclear receptor showed that the missense mutations are likely to affect the structure and stability of these domains. RNA in situ hybridization in mice revealed that Esrrb is expressed during inner-ear development, whereas immunohistochemical analysis showed that ESRRB is present postnatally in the cochlea. Our data indicate that ESRRB is essential for inner-ear development and function. To our knowledge, this is the first report of pathogenic mutations of an estrogen-related receptor gene.


Assuntos
Perda Auditiva/genética , Receptores Citoplasmáticos e Nucleares/genética , Receptores de Estrogênio/genética , Sequência de Aminoácidos , Cromossomos Humanos Par 14 , Análise Mutacional de DNA , Orelha Interna/embriologia , Orelha Interna/metabolismo , Feminino , Duplicação Gênica , Genes Recessivos , Ligação Genética , Humanos , Masculino , Repetições de Microssatélites , Modelos Moleculares , Dados de Sequência Molecular , Mutação de Sentido Incorreto , Linhagem , Isoformas de Proteínas/química , Isoformas de Proteínas/genética , Receptores Citoplasmáticos e Nucleares/química , Receptores de Estrogênio/química , Alinhamento de Sequência
17.
Audiol Neurootol ; 16(2): 93-105, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-21252500

RESUMO

In a Dutch family with autosomal recessive hearing loss, genome-wide single-nucleotide polymorphism analysis mapped the genetic defect to the DFNB7/11 locus. A novel homozygous A-to-G change in the TMC1 gene was detected near the splice donor site of intron 19 (c.1763+3A→G) segregating with the hearing loss in this family. One of the 6 transmembrane domains and the actual TMC channel domain are predicted to be absent in the mutant protein. The sensorineural hearing impairment in this DFNB7/11 family has a postlingual onset. Audiometric analysis initially showed a steeply downward-sloping threshold configuration. The progressive phenotype in this family resembles the phenotype previously described for families with dominant TMC1 mutations (DFNA36) rather than that of families with recessive TMC1 mutations (DFNB7/11) which invariably cause severe-to-profound prelingual hearing impairment.


Assuntos
Perda Auditiva Neurossensorial/genética , Perda Auditiva Neurossensorial/fisiopatologia , Proteínas de Membrana/genética , Doenças Vestibulares/genética , Doenças Vestibulares/fisiopatologia , Limiar Auditivo , Sequência de Bases , Progressão da Doença , Feminino , Genótipo , Perda Auditiva Neurossensorial/diagnóstico , Humanos , Masculino , Proteínas de Membrana/química , Dados de Sequência Molecular , Linhagem , Fenótipo , Mutação Puntual , Polimorfismo de Nucleotídeo Único , Estrutura Terciária de Proteína , Sítios de Splice de RNA/genética , Índice de Gravidade de Doença , Doenças Vestibulares/diagnóstico
18.
Ann Otol Rhinol Laryngol ; 120(6): 414-21, 2011 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-21774451

RESUMO

OBJECTIVES: We studied the clinical characteristics of an Australian family with an autosomal dominant sensorineural hearing impairment (DFNA9) caused by an I109N mutation in COCH. METHODS: Retrospective analyses of audiometric data from 8 mutation carriers of an Australian DFNA9 family with the I109N COCH mutation were performed. Cross-sectional hearing levels related to age, age-related typical audiograms, and speech recognition scores related to age and to the level of hearing impairment were investigated. Data were compared to those obtained in previously identified DFNA9 families with P51S, V66G, G87W, G88E, I109T, and C542F COCH mutations. RESULTS: Deterioration of hearing in the I109N mutation carriers started before the age of 40 years. The audiometric characteristics of the I109N mutation carriers are essentially similar to those previously established in I109T mutation carriers and, to a lesser extent, in P51S, G87W, and G88E mutation carriers. CONCLUSIONS: The phenotype associated with the I109N COCH mutation is largely similar to that associated with the I109T, P51S, G87W, and G88E mutation carriers. However, subtle differences seem to exist in terms of age of onset and rate of progression.


Assuntos
DNA/genética , Família , Perda Auditiva Neurossensorial/genética , Mutação , Proteínas/genética , Adulto , Audiometria de Tons Puros , Audiometria da Fala , Limiar Auditivo , Austrália/epidemiologia , Estudos Transversais , Análise Mutacional de DNA , Proteínas da Matriz Extracelular , Feminino , Predisposição Genética para Doença , Perda Auditiva Neurossensorial/epidemiologia , Perda Auditiva Neurossensorial/fisiopatologia , Heterozigoto , Humanos , Masculino , Linhagem , Fenótipo , Prevalência , Estudos Retrospectivos
19.
Ann Otol Rhinol Laryngol ; 120(6): 386-90, 2011 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-21774446

RESUMO

OBJECTIVES: We present indications and clinical outcomes of fitting an 8.5-mm abutment for bone conduction devices. METHODS: In 39 cases with a follow-up time of more than 12 months after fitting of an 8.5-mm abutment, the preintervention and postintervention courses were retrospectively evaluated. The outcome measures were indications for fitting and complications during the preintervention and postintervention courses (local skin reaction, skin level, revision surgery, and implant loss). RESULTS: Soft tissue overgrowth was the most frequent reason (31 of 39 cases) for fitting the 8.5-mm abutment. Severe skin reactions decreased by 7.9% after fitting, and the number of fixtures that remained free of any skin reaction increased by 32.2%. In 7 cases, soft tissue overgrowth required revision surgery before placement of the 8.5-mm abutment; further surgical intervention was needed only once. In 1 case, the 8.5-mm abutment was removed because of recurring soft tissue problems. No spontaneous abutment or implant loss occurred. CONCLUSIONS: This retrospective evaluation showed that fitting an 8.5-mm abutment is an easy step in managing soft tissue problems and preventing revision surgery. Also, it is of value in patients with a thick scalp that interferes with bone conduction device coupling. In these cases, we advise placing the 8.5-mm abutment during primary surgery.


Assuntos
Condução Óssea , Correção de Deficiência Auditiva/métodos , Perda Auditiva Condutiva/reabilitação , Cuidados Pós-Operatórios/métodos , Ajuste de Prótese , Adolescente , Adulto , Idoso , Criança , Pré-Escolar , Feminino , Seguimentos , Perda Auditiva Condutiva/cirurgia , Humanos , Magnetismo , Masculino , Pessoa de Meia-Idade , Osseointegração , Desenho de Prótese , Estudos Retrospectivos , Resultado do Tratamento , Adulto Jovem
20.
Ann Otol Rhinol Laryngol ; 120(4): 243-8, 2011 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-21585154

RESUMO

OBJECTIVES: We undertook to show that in a family with nonsyndromic autosomal dominant sensorineural hearing loss, genetic analysis can be successful when there is a match with a specific DFNA audioprofile. We also provide an update of relevant DFNA2/KCNQ4 audioprofiles and report the results of automatic audioprofile analysis using the Internet program AudioGene. METHODS: Audiometric data and blood samples were obtained from the family W08-0384. Based on the audiograms of the affected participants, mutation analysis of KCNQ4 was started. Original audiometric threshold data were collected for all identified KCNQ4-related DFNA2 families. The Internet computer program AudioGene, recently developed for automatic audioprofile analysis, was accessed. RESULTS: The family's audioprofile and the program AudioGene predicted the DFNA2/KCNQ4 locus. Mutation analysis of KCNQ4 revealed a c.821T>A (p.Leu274His) mutation of the KCNQ4 gene. This mutation has been previously identified in a Dutch family. Genetic analysis revealed a common haplotype in these two families over a region including the KCNQ4 gene. CONCLUSIONS: Familiarity with the audioprofiles of DFNA traits may lead to successful mutation analysis of the gene involved, even in a small family in which genetic linkage analysis is not an option. Alternatively, the specially developed program AudioGene can be accessed on the Internet to perform automatic audioprofile analysis of a family's (audiological) phenotype.


Assuntos
Análise Mutacional de DNA , Perda Auditiva Neurossensorial/genética , Canais de Potássio KCNQ/genética , Software , Audiometria de Tons Puros , Genes Dominantes , Haplótipos , Humanos , Masculino , Repetições de Microssatélites , Mutação , Países Baixos , Linhagem , Reação em Cadeia da Polimerase
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