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Concurrent hearing and genetic screening of newborns is expected to play important roles not only in early detection and diagnosis of congenital deafness, which triggers intervention, but also in predicting late-onset and progressive hearing loss and identifying individuals who are at risk of drug-induced HL. Concurrent hearing and genetic screening in the whole newborn population in Beijing was launched in January 2012. This study included 180,469 infants born in Beijing between April 2013 and March 2014, with last follow-up on February 24, 2018. Hearing screening was performed using transiently evoked otoacoustic emission (TEOAE) and automated auditory brainstem response (AABR). For genetic testing, dried blood spots were collected and nine variants in four genes, GJB2, SLC26A4, mtDNA 12S rRNA, and GJB3, were screened using a DNA microarray platform. Of the 180,469 infants, 1,915 (1.061%) were referred bilaterally or unilaterally for hearing screening; 8,136 (4.508%) were positive for genetic screening (heterozygote, homozygote, or compound heterozygote and mtDNA homoplasmy or heteroplasmy), among whom 7,896 (4.375%) passed hearing screening. Forty (0.022%) infants carried two variants in GJB2 or SLC26A4 (homozygote or compound heterozygote) and 10 of those infants passed newborn hearing screening. In total, 409 (0.227%) infants carried the mtDNA 12S rRNA variant (m.1555A>G or m.1494C>T), and 405 of them passed newborn hearing screening. In this cohort study, 25% of infants with pathogenic combinations of GJB2 or SLC26A4 variants and 99% of infants with an m.1555A>G or m.1494C>T variant passed routine newborn hearing screening, indicating that concurrent screening provides a more comprehensive approach for management of congenital deafness and prevention of ototoxicity.
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Testes Genéticos/métodos , Perda Auditiva/diagnóstico , Pequim , Teste em Amostras de Sangue Seco , Feminino , Predisposição Genética para Doença , Humanos , Recém-Nascido , MasculinoRESUMO
Background Hereditary sensorineural hearing loss is a genetically heterogeneous disorder. Objectives This study was designed to explore the genetic etiology of deafness in a large Chinese family with autosomal dominant, nonsyndromic, progressive sensorineural hearing loss (ADNSHL). Methods Whole exome sequencing and linkage analysis were performed to identify pathogenic mutation. Inner ear expression of Ifnlr1 was investigated by immunostaining in mice. ifnlr1 Morpholino knockdown Zebrafish were constructed to explore the deafness mechanism. Results We identified a cosegregating heterozygous missense mutation, c.296G>A (p.Arg99His) in the gene encoding interferon lambda receptor 1 (IFNLR1) - a protein that functions in the Jak/ STAT pathway- are associated with ADNSHL Morpholino knockdown of ifnlr1 leads to a significant decrease in hair cells and non-inflation of the swim bladder in late-stage zebrafish, which can be reversed by injection with normal Zebrafish ifnlr1 mRNA. Knockdown of ifnlr1 in zebrafish causes significant upregulation of cytokine receptor family member b4 (interleukin-10r2), jak1, tyrosine kinase 2, stat3, and stat5b in the Jak1/STAT3 pathway at the mRNA level. ConclusionIFNLR1 function is required in the auditory system and that IFNLR1 mutations are associated with ADNSHL. To the best of our knowledge, this is the first study implicating an interferon lambda receptor in auditory function.
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Predisposição Genética para Doença , Perda Auditiva Neurossensorial/genética , Receptores de Citocinas/genética , Receptores de Interferon/genética , Animais , Técnicas de Silenciamento de Genes , Ligação Genética , Perda Auditiva Neurossensorial/fisiopatologia , Heterozigoto , Humanos , Janus Quinase 1/genética , Camundongos , Morfolinas , Mutação de Sentido Incorreto/genética , Fator de Transcrição STAT3/genética , Transdução de Sinais , Sequenciamento do Exoma , Peixe-Zebra/genéticaRESUMO
Hereditary hearing loss is characterized by a high degree of genetic heterogeneity. Mutations in the TMPRSS3 (transmembrane protease, serine 3) gene cause prelingual (DFNB10) or postlingual (DFNB8) deafness. In our previous study, three pathogenic mutations in TMPRSS3 were identified in one Chinese family. To evaluate the importance of TMPRSS3 mutations in recessive deafness among the Chinese, we screened 150 autosomal recessive nonsyndromic hearing loss (ARNSHL) families and identified 6 that carried seven causative TMPRSS3 mutations, including five novel mutations (c.809T>A, c.1151T>G, c.1204G>A, c.1244T>C, and c.1250G>A) and two previously reported mutations (c.323-6G>A and c.916G>A). Each of the five novel mutations was classified as severe, by both age of onset and severity of hearing loss. Together with our previous study, six families were found to share one pathogenic mutation (c.916G>A, p.Ala306Thr). To determine whether this mutation arose from a common ancestor, we analyzed six short tandem repeat (STR) markers spanning the TMPRSS3 gene. In four families, we observed linkage disequilibrium between p.Ala306Thr and STR markers. Our results indicate that mutations in TMPRSS3 account for about 4.6% (7/151) of Chinese ARNSHL cases lacking mutations in SLC26A4 or GJB2 and that the recurrent TMPRSS3 mutation p.Ala306Thr is likely to be a founder mutation.
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Perda Auditiva Neurossensorial/genética , Proteínas de Membrana/genética , Mutação , Proteínas de Neoplasias/genética , Serina Endopeptidases/genética , Adulto , Idade de Início , Criança , Pré-Escolar , China , Análise Mutacional de DNA , Feminino , Perda Auditiva Neurossensorial/diagnóstico , Humanos , Recém-Nascido , Masculino , Índice de Gravidade de Doença , Adulto JovemRESUMO
Hereditary nonsyndromic hearing loss is extremely heterogeneous. Mutations in the transmembrane channel-like gene1 (TMC1) are known to cause autosomal dominant and recessive forms of nonsyndromic hearing loss linked to the loci of DFNA36 and DFNB7/11, respectively. We characterized a six-generation Chinese family (5315) with progressive, postlingual autosomal dominant nonsyndromic hearing loss (ADNSHL). By combining targeted capture of 82 known deafness genes, next-generation sequencing and bioinformatic analysis, we identified TMC1 c.1714G>A (p. D572N) as the disease-causing mutation. This mutation co-segregated with hearing loss in other family members and was not detected in 308 normal controls. In order to determine the prevalence of TMC1 c.1714G>A in Chinese ADNSHL families, we used DNA samples from 67 ADNSHL families with sloping audiogram and identified two families carry this mutation. To determine whether it arose from a common ancestor, we analyzed nine STR markers. Our results indicated that TMC1 c.1714G>A (p.D572N) account for about 4.4% (3/68) of ADNSHL in the Chinese population.
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Biologia Computacional/métodos , Perda Auditiva Neurossensorial/genética , Proteínas de Membrana/genética , Mutação , Adulto , Povo Asiático , Audiometria , Sequência de Bases , Estudos de Casos e Controles , Criança , Análise Mutacional de DNA , Feminino , Expressão Gênica , Genes Dominantes , Loci Gênicos , Marcadores Genéticos , Perda Auditiva Neurossensorial/etnologia , Perda Auditiva Neurossensorial/patologia , Heterozigoto , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , Masculino , Dados de Sequência Molecular , LinhagemRESUMO
BACKGROUND: Mutations in MPZL2, the characteristic genetic etiology of autosomal recessive deafness loci 111 (DFNB111), cause non-syndromic and moderate sensorineural hearing loss. METHODS: In this study, we analyzed the phenotype and genotype of eight pedigrees consisting of 10 hearing loss patients with bi-allelic pathogenic or likely pathogenic variants in MPZL2. These patients were identified from a 3272 Chinese patient cohort who underwent genetic testing. RESULTS: Apart from symmetrical and moderate sensorineural hearing loss, the MPZL2-related phenotype was characterized by progressive hearing loss with variation in the onset age (congenital defect to onset at the young adult stage). We determined that in the Chinese population, the genetic load of MPZL2 defects was 0.24% (8/3272) in patients diagnosed with hearing loss and 7.02% (8/114) in patients diagnosed with hereditary moderate sensorineural hearing loss caused by STRC, OTOA, OTOG, OTOGL, TECTA, MPZL2 and others. Three known MPZL2 variants (c.220C > T (p.Gln74*), c.68delC (p.Pro23Leufs*2), c.463delG (p.Ala155Leufs*10)) and a novel start loss variant (c.3G > T (p.Met1?)) were identified. MPZL2 c.220C > T was identified as the hotspot variant in the Chinese population and even in East Asia compared with c.72delA (p.Ile24Metfs*22) in European and West Asia through allele frequency. CONCLUSIONS: We concluded that apart from moderate HL, progressive HL is another character of MPZL2-related HL. No specified variant was verified for the progression of HL, the penetrance and expressivity cannot be determined yet. A novel MPZL2 variant at the start codon was identified, enriching the variant spectrum of MPZL2. The hotspot variants of MPZL2 vary in different ethnicities. This study provides valuable data for the diagnosis, prognosis evaluation and genetic counseling of patients with moderate sensorineural hearing loss related to MPZL2.
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Surdez , Perda Auditiva Neurossensorial , Humanos , Adulto Jovem , Povo Asiático/genética , Moléculas de Adesão Celular , China , Surdez/etnologia , Surdez/genética , Perda Auditiva Neurossensorial/etnologia , Perda Auditiva Neurossensorial/genética , Peptídeos e Proteínas de Sinalização Intercelular , Proteínas de MembranaRESUMO
BACKGROUND: Inherited genetic defects play an important role in congenital hearing loss, contributing to about 60% of deafness occurring in infants. Hereditary nonsyndromic hearing loss is highly heterogeneous, and most patients with a presumed genetic etiology lack a specific molecular diagnosis. METHODS: By whole exome sequencing, we identified responsible gene of family 4794 with autosomal recessively nonsyndromic hearing loss (ARNSHL). We also used DNA from 56 Chinese familial patients with ARNSHL (autosomal recessive nonsyndromic hearing loss) and 108 ethnicity-matched negative samples to perform extended variants analysis. RESULTS: We identified MYO15A c.IVS25+3G>A and c.8375 T>C (p.V2792A) as the disease-causing mutations. Both mutations co-segregated with hearing loss in family 4794, but were absent in the 56 index patients and 108 ethnicity-matched controls. CONCLUSIONS: Our results demonstrated that the hearing loss of family 4794 was caused by novel compound heterozygous mutations in MYO15A.
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Exoma , Genes Recessivos , Perda Auditiva/genética , Heterozigoto , Mutação , Miosinas/genética , Análise de Sequência , Adulto , Animais , Sequência de Bases , China , DNA/genética , Feminino , Perda Auditiva/fisiopatologia , Testes Auditivos , Humanos , Masculino , Dados de Sequência Molecular , Miosinas/química , Linhagem , Homologia de Sequência de Aminoácidos , Homologia de Sequência do Ácido NucleicoRESUMO
BACKGROUND: IFNLR1 has been recently identified to be related to autosomal dominant nonsyndromic sensorineural hearing loss (ADNSHL). It is reported to be expressed in the inner ear of mice and the lateral line of zebrafish. However, it remains unclear how defects in this gene lead to hearing loss. OBJECTIVES: To elucidate the global gene expression changes in zebrafish when the expression of ifnlr1 is downregulated. METHODS: Transcriptome analysis was performed on ifnlr1 morpholino knockdown zebrafish and the control zebrafish using RNA-seq technology. RESULTS: The results show that 262 differentially expressed genes (DEGs) were up-regulated while 146 DEGs were down-regulated in the E4I4-Mo zebrafish larvae compared to the control-Mo. Six pathways were significantly enriched, including steroid biosynthesis pathway, adipocytokine signaling pathway, cytokine-cytokine receptor interaction pathway, p53 signaling pathway, AGE-RAGE signaling pathway in diabetic complications, and terpenoid backbone biosynthesis pathway. Among them, three pathways (steroid biosynthesis pathway, cytokine-cytokine receptor interaction pathway and p53 signaling pathway) are immune-associated. CONCLUSIONS: The transcriptome analysis results contribute to the groundwork for future research on the pathogenesis of IFNLR1-associated hearing loss.
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Transcriptoma , Peixe-Zebra , Animais , Citocinas , Perfilação da Expressão Gênica , Imunidade , Receptores de Citocinas/genética , Esteroides , Proteína Supressora de Tumor p53/genética , Peixe-Zebra/genéticaRESUMO
Pathogenic variants in MYO15A are known to cause autosomal recessive nonsyndromic hearing loss (ARNSHL), DFNB3. We have previously reported on one ARNSHL family including two affected siblings and identified MYO15A c.5964+3G > A and c.8375 T > C (p.Val2792Ala) as the possible deafness-causing variants. Eight year follow up identified one new affected individual in this family, who also showed congenital, severe to profound sensorineural hearing loss. By whole exome sequencing, we identified a new splice-site variant c.5531+1G > C (maternal allele), in a compound heterozygote with previously identified missense variant c.8375 T > C (p.Val2792Ala) (paternal allele) in MYO15A as the disease-causing variants. The new affected individual underwent unilateral cochlear implantation at the age of 1 year, and 5 year follow-up showed satisfactory speech and language outcomes. Our results further indicate that MYO15A-associated hearing loss is good candidates for cochlear implantation, which is in accordance with previous report. In light of our findings and review of the literatures, 58 splice-site variants in MYO15A are correlated with a severe deafness phenotype, composed of 46 canonical splice-site variants and 12 non-canonical splice-site variants.
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Surdez , Perda Auditiva , Humanos , Linhagem , Miosinas/genética , Surdez/genética , Perda Auditiva/genética , Fenótipo , Família , GenótipoRESUMO
Four new quaternary isostructural rare-earth thiosilicates, ZnY(6)Si(2)S(14) (1), Al(0.50)Dy(3)(Si(0.50)Al(0.50))S(7) (2), Al(0.38)Dy(3)(Si(0.85)Al(0.15))S(7) (3), and Al(0.33)Sm(3)SiS(7) (4), crystallized in the chiral and polar space group P6(3), have been prepared by a facile synthetic routine. Compounds 1-3 show strong second harmonic generation effects at 2.1 um with the intensities of 1, 2, and 3 being about 2, 2, and 1 times that of KTP (KTiOPO(4)), respectively. The calculated band structure of 1 implies that the optical absorptions of BLn(6)M(2)Q(14) and ALn(3)MQ(7) family compounds are mainly ascribed to the charge transitions from Q-p to Ln-4f (4d for Y) states. Compounds 2-4 exhibit antiferromagnetic-like interactions.
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OBJECTIVE: To invesigate the molecular pathogenesis of deafness among the youth by means of genetic testing so as to provide pre-marriage genetic counseling and instruction for the deaf youth. METHODS: 217 deaf young people, 126 males and 91 females, aged 18.9 (16 - 26), from Yunnan and Guizhou provinces, underwent history taking, auditory testing, and collection of peripheral blood samples. Genomic DNA and mitochondrial DNA were extracted to undergo sequence analysis of the entire gene GJB2, common point mutation of SLC26A4 gene, and mutation of mtDNA A1555G. Genetic prediction and marriage instruction were provided to each subject based on these results. RESULTS: Twenty-three of the 117 persons (10.5%), 13 males and 10 females, were mtDNA A1555G mutation carriers and they were instructed that they, their maternal relatives, and the offspring of the female carriers, should they be born, should strictly avoid the administration of amino glycoside antibiotics. Twenty eight of the 115 persons (12.9%), were confirmed to carry homozygous or compound GJB2 mutations, 5 individuals (2.3%) carried heterozygous GJB2 mutation, 19 (8.8%) carried homozygous or compound SLC26A4 mutations, and one (0.5%) carried heterozygous SLC26A4 mutation. The suggestion for them was to avoid getting married with deaf partners caused by the same deaf gene or with individuals carrying mutations in the same deaf gene. Meanwhile, suggestions such as avoiding aggressive exercises and head injury were provided to the deaf young people with SLC26A4 mutations. CONCLUSION: Genetic testing can provide more accurate and useful genetic counseling and instruction to deaf young people for their partner selection and eugenics.
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Surdez/prevenção & controle , Aconselhamento Genético , Exames Pré-Nupciais , Adolescente , Adulto , China/epidemiologia , Conexina 26 , Conexinas , Surdez/epidemiologia , Surdez/genética , Feminino , Humanos , Masculino , Adulto JovemRESUMO
OBJECTIVE: To investigate the Gap junction protein beta 2 (GJB2) gene mutation in cochlear implantation (CI) recipients and the treatment outcome of CI in the CI recipients with GJB2 gene mutation. METHODS: Peripheral blood samples were collected from 253 CI recipients with autosomal recessive non-syndromic hearing impairment (NSHI), 174 males and 79 females, aged (8 +/- 9) (112 months-52.7 years), and 301 children with normal hearing level as controls. PCR was used to detect the GJB2 mutations. The auditory threshold with CI and speech recognition of the CI recipients with GJB2 mutation were compared with those of the CI recipients without GJB2 mutation (control group). Questionnaire survey, with meaningful auditory integration scale (MAIS), categories of auditory performance (CAP), and speech intelligibility rating (SIR), was used for young infants. RESULTS: Sixty-seven of the 253 CI recipients (26.5%) were found to have GJB2 mutations. One novel mutation, GJB2 235delC/598G > A, was identified. The detection rates of GJB2 mutations in the CI recipients were significantly higher than those among the controls (all P < 0.05). The postoperative outcomes of CI in both the GJB2 gene mutation positive and negative groups were very good, however, without significant differences among these 2 groups (all P > 0.05). CONCLUSION: GJB2 gene mutation is one of the major causes for CI recipients with autosomal recessive NSHI. The treatment outcomes of CI recipients with GJB2 gene mutations under 7 years old are satisfying.
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Implante Coclear , Conexinas/genética , Surdez/genética , Mutação , Adolescente , Adulto , Criança , Pré-Escolar , Conexina 26 , Surdez/cirurgia , Feminino , Humanos , Lactente , Masculino , Pessoa de Meia-Idade , Resultado do Tratamento , Adulto JovemRESUMO
OBJECTIVE: To investigate the molecular etiology of non-syndromic hearing impairment in two patients in a maternal inherited deafness Chinese family. METHODS: Peripheral blood specimens were collected and DNA templates extracted. The complete mitochondrial genomes and GJB2 gene were sequenced in an ABI 3100 Avant sequencer. RESULTS: The proband (III-5) and her elder sister (III-1) were found to carry the mtDNA 12SrRNA C1494T mutation. The GJB2 gene showed no mutations. The proband had the history of using aminoglycosides before hearing loss, and exhibited severe sensorineural hearing impairment; the proband's sister had no history of using aminoglycosides, and showed moderate sensorineural hearing impairment. CONCLUSION: The molecular etiology of each individual patient in a family yaries with individual genetic background.
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Conexinas/genética , Perda Auditiva/genética , Proteínas de Membrana Transportadoras/genética , Adulto , Povo Asiático/genética , Conexina 26 , DNA Mitocondrial/genética , Feminino , Perda Auditiva/etiologia , Humanos , Pessoa de Meia-Idade , Mutação , Linhagem , Análise de Sequência de DNA , Transportadores de SulfatoRESUMO
A novel 3-D (3,6)-connected topological architecture, obtained by reacting Cd(ClO4)2 x 6H2O with Htrtr (Htrtr = 3-(1,2,4-triazole-4-yl)-1H-1,2,4-triazole) under solvothermal conditions, presents a non-centrosymmetric polar packing arrangement, resulting in a strong second harmonic generation (SHG) response and ferroelectric property.
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Warrgenburg syndrome type 2 (WS2) is the most common autosomal dominantly-inherited syndrome with hearing loss. MITF (microphthalmia associated transcription factor)is a basic-helix-loop-helix-luecine zipper (bHLHZip) factor which regulates expression of tyrosinase, and is involved in melanocyte differentiation. Mutations in MITF associated with WS2 have been identified in some but not all affected families. Here, we report a three-generation Chinese family with a point mutation in the MITF gene causing WS2. The proband exhibits congenital severe sensorineural hearing loss, heterochromia iridis and facial freckles. One of family members manifests sensorineural deafness, and the other patients show premature greying or/and freckles. This mutation, heterozygous deletion c.639delA, creates a stop codon in exon 7 and is predicted to result in a truncated protein lacking normal interaction with its target DNA motif. This mutation is a novel mutation and the third case identified in exon 7 of MITF in WS2. Though there is only one base pair distance between this novel mutation and the other two documented cases and similar amino acids change, significant difference is seen in clinical phenotype, which suggests genetic background may play an important role.
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Fator de Transcrição Associado à Microftalmia/genética , Síndrome de Waardenburg/genética , Adolescente , Adulto , Criança , Análise Mutacional de DNA , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Mutação , Linhagem , Reação em Cadeia da Polimerase , Adulto JovemRESUMO
Fast radio bursts (FRBs), bright transients with millisecond durations at â¼GHz and typical redshifts probably >0.8, are likely to be gravitationally lensed by intervening galaxies. Since the time delay between images of strongly lensed FRB can be measured to extremely high precision because of the large ratio â¼109 between the typical galaxy-lensing delay time [Formula: see text] (10 days) and the width of bursts [Formula: see text] (ms), we propose strongly lensed FRBs as precision probes of the universe. We show that, within the flat ΛCDM model, the Hubble constant H0 can be constrained with a ~0.91% uncertainty from 10 such systems probably observed with the square kilometer array (SKA) in <30 years. More importantly, the cosmic curvature can be model independently constrained to a precision of â¼0.076. This constraint can directly test the validity of the cosmological principle and break the intractable degeneracy between the cosmic curvature and dark energy.
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BACKGROUND: Safe cochlear implantation (CI) is challenging in patients with a canal wall down (CWD) mastoidectomy cavity. OBJECTIVES: We reviewed the outcomes of CI and proposed surgical management principles according to the presentation status of CWD mastoidectomy cavity. MATERIAL AND METHODS: The cases of eight patients (nine ears) with CWD mastoidectomy cavity who underwent CI were retrospectively reviewed. The basis of the surgical decision, postoperative complications, and postimplant auditory performance were analysed. RESULTS: In seven patients (eight ears), implantation was performed in a single stage; in six ears, the external auditory canal (EAC) was oversewn. In two patients with ossification, the electrode array was inserted into the scala tympani by drilling of the basal turn or in the second turn of the cochlea through a drill-out procedure. Seven patients had a follow-up of 12-50 months and one patient was lost to follow-up. None of the followed-up seven patients suffered complications. CONCLUSIONS: CI is safe and effective in patients with profound hearing loss after radical mastoidectomy. In patients with CWD mastoidectomy cavity, CI does not cause a higher rate of postoperative complications relative to standard CI procedures. The outcome is excellent and comparable to that in the general CI population.
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Implante Coclear/métodos , Perda Auditiva Neurossensorial/diagnóstico , Perda Auditiva Neurossensorial/cirurgia , Mastoidectomia/métodos , Segurança do Paciente , Adulto , Idoso , Audiometria/métodos , Terapia Combinada/métodos , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Medição de Risco , Estudos de Amostragem , Índice de Gravidade de Doença , Tomografia Computadorizada por Raios X/métodos , Resultado do Tratamento , Adulto JovemRESUMO
Hereditary nonsyndromic hearing loss is extremely heterogeneous. Mutations in the POU class 4 transcription factor 3 (POU4F3) are known to cause autosomal dominant nonsyndromic hearing loss linked to the loci of DFNA15. In this study, we describe a pathogenic missense mutation in POU4F3 in a four-generation Chinese family (6126) with midfrequency, progressive, and postlingual autosomal dominant nonsyndromic hearing loss (ADNSHL). By combining targeted capture of 129 known deafness genes, next-generation sequencing, and bioinformatic analysis, we identified POU4F3 c.602T>C (p.Leu201Pro) as the disease-causing variant. This variant cosegregated with hearing loss in other family members but was not detected in 580 normal controls or the ExAC database and could be classified as a "pathogenic variant" according to the American College of Medical Genetics and Genomics guidelines. We conclude that POU4F3 c.602T>C (p.Leu201Pro) is related to midfrequency hearing loss in this family. Routine examination of POU4F3 is necessary for the genetic diagnosis of midfrequency hearing loss.
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Povo Asiático/genética , Perda Auditiva Neurossensorial/genética , Proteínas de Homeodomínio/genética , Mutação de Sentido Incorreto/genética , Fator de Transcrição Brn-3C/genética , Adulto , Idoso , Sequência de Aminoácidos , Sequência de Bases , Pré-Escolar , Análise Mutacional de DNA , Família , Feminino , Proteínas de Homeodomínio/química , Humanos , Pessoa de Meia-Idade , Linhagem , Fator de Transcrição Brn-3C/químicaRESUMO
OBJECTIVE: To investigate the prevalence of GJB2 mutations in Uigur and Han ethnic groups in Xinjiang Uigur Autonomous Region, China and to understand the mutation spectrum and frequency of the GJB2 gene in these 2 ethnic groups. METHODS: Questionnaire survey was conducted among 61 Uigur deaf-mute students, 60 Han deaf-mute students, and 98 normal Uigurs and 301 normal Han people as controls. Peripheral blood samples were collected to undergo PCR and sequencing of GJB2 gene. RESULTS: The GJB2 mutation rate of the Uigur deaf-mute students was 19.7%, not significantly different from that of the Han deaf-mute students (17.2%). GJB2 35delG was found only in the Uigur deaf-mutes with a carrier rate of 11.5%, whereas 235delC was identified in both Uigur and Han deaf-mutes. The allelic frequency of 35delG mutation in the Uigur and Han deaf-mutes and the Uigur controls were 7.4% (9/122), 0 (0/128), and 0 (0/196) respectively. The allelic frequencies of the GJB2 235delC mutations in the Uigur and Han deaf-mute students were 5.7% and 9.8%, and the allelic frequencies of 299 - 300delAT were 0.8% and 5.5%. V27I and E114G were the most frequent types of polymorphism. CONCLUSION: There is a rather high mutation rate of GJB2 gene in Xinjiang. The carrier frequency of 35delG of the Uigurs is significantly higher than that of the Han population. 235delC is common in both Uigur and Han people.
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Conexinas/genética , Surdez/genética , Mutação , Adolescente , Criança , China/epidemiologia , Conexina 26 , Análise Mutacional de DNA , Surdez/etnologia , Feminino , Frequência do Gene , Genótipo , Humanos , Masculino , Reação em Cadeia da Polimerase , Inquéritos e QuestionáriosRESUMO
OBJECTIVE: To analyze the molecular genetic mechanisms of pathogenesis of deafness in the families with deaf-mute patients and analyze the strategies of genetic counseling and intervention for these families. METHODS: Peripheral blood samples were collected from the probands with deaf-muteness and their parents of five families and genetic tests were conducted to analyze the GJB2, SLC26A4 (PDS), and mitochondrial DNA (mtDNA) A 1555G genes for the existence of mutation. Families 1-3 had one child with hearing loss each while the parents had normal hearing and the mothers had been pregnant for 6-18 weeks. Both parents of family 4 were deaf-mute, and the wife of family 5 was deaf-mute while her husband had normal hearing. RESULTS: The proband from family 1 was proven to carry compound GJB2 mutations while his parents carried a single GJB2 mutation; prenatal testing showed that the fetus only carried the paternal mutation. The proband from family 2 was proven to carry compound SLC26A4 (PDS) mutations while his parents carried a single SLC26A4 (PDS) mutation; prenatal testing showed that the fetus only carried the paternal mutation. The proband from family 3 and his parents didn't carry any GJB2, SLC26A4 and mtDNA A1555G mutation. Observation showed that the new born babies of these three families all had normal hearing revealed by new born hearing screening and ABR test. The husband from family 4 was homozygous GJB2 235delC while his wife was mtDNA A1555G positive. This couple was advised to strictly avoid the administration of aminoglycoside antibiotics to their future offspring. In family 5, the wife carried compound SLC26A4 (PDS) mutations while her husband carried a single SLC26A4 (PDS) mutation; and they were told about the 50% risk of their offspring's suffering from enlarged vestibular aqueduct syndrome. CONCLUSION: Genetic testing with prenatal testing and relevant intervention for the families with deaf-mute patients can be applied to prevent another deaf-mute member from being born.