Analysis of 59 cases of large vestibular aqueduct syndrome SLC26A4gene mutation frequency and new mutation sites / 临床耳鼻咽喉头颈外科杂志

Objective:To study the frequency of SLC26A4 gene mutation sites in children with enlarged vestibular aqueduct deafness in Yunnan, report the new mutation sites of SLC26A4 gene, further clarify the mutation spectrum of SLC26A4gene, and explore the association between biallelic and monoallelic mutations of SLC26A4 gene and CT phenotype of inner ear, so as to provide basis for clinical and genetic diagnosis of deafness. Methods:Review the results of temporal bone CT examination of 390 children after cochlear implantation in the Department of Otolaryngology, Kunming Children's Hospital from August 2016 to September 2021. Sanger sequencing of SLC26A4 gene was performed in 59 children with enlarged vestibular aqueduct. According to the genetic test results, the children who underwent temporal bone CT examination were divided into two groups: SLC26A4 biallelic mutation group（homozygous mutation and compound heterozygous mutation）, monoallelic mutation group, and the association with inner ear CT phenotype was analyzed, and the new sites were summarized and analyzed. Results:The c.919-2a>g mutation was the most common mutation in children with enlarged vestibular aqueduct with SLC26A4 gene mutation. Three new variants of SLC26A4 gene were found; CT examination combined with genetic testing found that a part of children with enlarged vestibular aqueduct was associated with SLC26A4 monoallelic mutation or no SLC26A4 gene mutation was detected. Further research is needed to investigate the involvement of other pathogenic factors in the pathogenesis of EVA.

Pendred syndrome with hyperthyroidism / Journal of Rural Medicine

Objectives: Pendred syndrome is an autosomal recessive disorder characterized by the combination of sensorineural deafness and goiter and is caused by biallelic mutations in the SLC26A4/PDS gene. Thyroid function is generally reported as euthyroid or hypothyroid in this condition. We present a case of Pendred syndrome with hyperthyroidism.Patient: An 83-year-old woman with congenital deaf–mutism presented with complaints of nausea. She developed a large goiter and had hearing impairment. Her hearing level was 105 dB in both ears. She presented with hyperthyroidism and was treated with thiamazole.Results: She had a homozygous mutation in c.1579A>C:p.T527P of the SLC26A4 gene, confirming a diagnosis of Pendred syndrome.Conclusion: Pendred syndrome may develop into hyperthyroidism if the size of the goiter increases. Moreover, a homozygous mutation in c.1579A>C:p.T527P of the SLC26A4 gene, which was previously reported to be associated with nonsyndromic hearing loss with enlarged vestibular aqueduct, may also cause Pendred syndrome.

Two Compound Heterozygous Were Identified in SLC26A4 Gene in Two Chinese Families With Enlarged Vestibular Aqueduct

OBJECTIVES: To investigate the genetic causes of hearing loss with enlarged vestibular aqueduct (EVA) in two children from unrelated two Chinese families. METHODS: Sanger sequencing of all coding exons in SLC26A4 (encoding Pendrin protein) was performed on the two patients, their sibling and parents respectively. To predict and visualize the potential functional outcome of the novel variant, model building, structure analysis, and in silico analysis were further conducted. RESULTS: The results showed that the proband from family I harbored a compound heterozygote of SLC26A4 c.1174A>T (p.N392Y) mutation and c.1181delTCT (p.F394del) variant in exon 10, potentially altering Pendrin protein structure. In family II, the proband was identified in compound heterozygosity with a known mutation of c.919-2A>G in the splice site of intron 7 and a novel mutation of c.1023insC in exon 9, which results in a frameshift and translational termination, consequently leading to truncated Pendrin protein. Sequence homology analysis indicated that all the mutations localized at high conservation sites, which emphasized the significance of these mutations on Pendrin spatial organization and function. CONCLUSION: In summary, this study revealed two compound heterozygous mutations (c.1174A>T/c.1181delTCT; c.919- 2A>G/c.1023insC) in Pendrin protein, which might account for the deafness of the two probands clinically diagnosed with EVA. Thus this study contributes to improve understanding of the causes of hearing loss associated with EVA and develop a more scientific screening strategy for deafness.

СОНСГОЛЫН ХҮНД ХЭЛБЭРИЙН БУУРАЛТТАЙ ХҮНД CONNEXIN 26 ГЕНИЙН МУТАЦИЙГ ТОДОРХОЙЛСОН ТӨСӨЛТ АЖЛЫН ЗАРИМ ҮР ДҮН / Шинэ санаа Шинэ нээлт

@#BACKGROUND. Sensorineural hearing impairment (SNHI) is the most common inherited sensory defect, affecting about 3 per 1000 children. More than 50% of these patients have a genetic cause (i.e. hereditary hearing impairment; HHI). Mutations in certain genes were noted to be extraordinarily popular in the deaf patients across different populations, making molecular screening feasible for these common deafness genes. One of the most important characteristics that we have learned concerning hereditary hearing loss is that common deafness genes and their mutations are usually different according to the ethnic background. As demonstrated in our previous studies performed in Taiwanese patients, the mutation spectrums of common deafness genes, such as the GJB2 gene and the SLC26A4 gene, are different from those in the Caucasian or even other Asian populations. These findings further underscore the indispensability of the collection of local data in terms of genetic counseling. In the collaborative project, we have successfully established a cohort of >100 hearingimpaired families, and clarified the genetic epidemiology of deafness in the Mongolian population. We identified several special deafness mutations such as GJB2 c.23+1G>A, c.559_604dup, and SLC26A4 c.919-2A>G, and our results revealed that Mongolian patients demonstrate a unique genetic profile in deafness as compared to other East Asian populations (paper in preparation). Meanwhile, by organizing a seminar at National Taiwan University Hospital in March 2017, we have transferred crucial concepts and techniques regarding how to perform genetic testing for deafness to the Mongolian colleagues. In the future, we plan to strengthen the mutual collaboration by expanding the clinical cohort and upgrading the genetic examination platform using the NGS techniques.

Genetic analysis and prenatal diagnosis for patients with non-syndromic hearing impairment / 天津医药

Objective To explore the genetic pathogen of patients with non-syndromic hearing impairment and to provide prenatal diagnosis for the families of hereditary deafness. Methods Mutation screening of GJB2, SLC26A4, GJB3 and mitochondrial 12 S rRNA genes was performed in 208 patients with non-syndromic hearing impairment by gene chip. Then direct sequencing was used in 41 patients who were found one mutation of GJB2 or SLC26A4 gene. And prenatal diagnosis was carried out in two families by direct sequencing. Results Eighty-six patients (41.35％) were found at least one mutation by gene chip. Among them, 40 patients were found to carry two mutations and 46 patients were found to carry one mutation. The most frequent mutation was 235delC, which was found in 46 patients. And 12 cases were found the second mutation through direct sequencing. A total of 52 (25.00％) patients were detected two mutations. Prenatal diagnosis showed that one fetus carried compound mutations of 299-300delAT and 235delC, and another one carried heterozygous mutation of IVS7-2A>G. Conclusion Patients with non-syndromic hearing impairment can be accurately diagnosed by gene chip and Sanger sequencing. The prenatal diagnosis is primary means for high-risk fetuses.

Analysis of deafness-associated mutant genes and pedigrees in neonates / 预防医学

Objective To carry out mutation analysis of deafness-associated genes for deaf newborns and their parents, and to estimate the recurrence risk for their parents to have deaf descendants.Methods Suspected cases of inherited deafness were identified by neonatal hearing screening and questionnaires. Genomic DNAs of suspected cases and their parents were extracted from their peripheral blood samples . Common deafness-associated genes(i.e. GJB2,SLC26A4 and 12S rRNA genes)were amplified by polymerase chain reaction(PCR),and those PCR products were sequenced for the mutation analysis.Results From 2013 to 2016, 193 cases of deafness were found in neonatal hearing screening,29 cases of suspected as hereditary deafness were screened,and 17 out of 29 cases were found to have mutations in deafness-associated genes(detection rate:58.62%). GJB2 homozygous mutations were identified in two cases and their parents,and the recurrence risk to have deaf descendants was 100%. Four cases of suspected hereditary deafness had GJB2 homozygous mutations,and their parents were both GJB2 mutation carriers. There was one case with SLC26A4 homozygous mutations,and their parents were both SLC26A4 mutation carrier. Two cases were detected to have GJB2 V371 homozygous mutations,and their parents were both GJB2 V371 mutation carriers. For those seven parents carrying deafness-associated mutations above,the recurrence risk of deafness for their descendants was 25%.Conclusion In addition to hearing screening,the genetic diagnosis of deafness-associated genes is helpful to clarify the cause of suspected neonatal hereditary deafness,and can provide objective reproductive counseling and guidance for those deaf parents or parents with deaf children.

МОНГОЛ ХҮНИЙ ТӨРӨЛХИЙН БОЛОН ОЛДМОЛ ХЭЛБЭРИЙН ДҮЛИЙН ҮЕИЙН CONNEXIN 26 ГЕНИЙН МУТАЦИЙГ ТОДОРХОЙЛСОН СУДАЛГААНЫ АЖЛЫН ЗАРИМ ҮР ДҮН / Шинэ санаа Шинэ нээлт

@#BACKGROUND. Sensorineural hearing impairment (SNHI) is the most common inherited sensory defect, affecting about 3 per 1000 children. More than 50% of these patients have a genetic cause (i.e. hereditary hearing impairment; HHI). Mutations in certain genes were noted to be extraordinarily popular in the deaf patients across different populations, making molecular screening feasible for these common deafness genes. One of the most important characteristics that we have learned concerning hereditary hearing loss is that common deafness genes and their mutations are usually different according to the ethnic background. As demonstrated in our previous studies performed in Taiwanese patients, the mutation spectrums of common deafness genes, such as the GJB2 gene and the SLC26A4 gene, are different from those in the Caucasian or even other Asian populations. These findings further underscore the indispensability of the collection of local data in terms of genetic counseling. In the collaborative project, we have successfully established a cohort of >100 hearing-impaired families, and clarified the genetic epidemiology of deafness in the Mongolian population. We identified several special deafness mutations such as GJB2 c.23+1G>A, c.559_604dup, and SLC26A4 c.919-2A>G, and our results revealed that Mongolian patients demonstrate a unique genetic profile in deafness as compared to other East Asian populations (paper in preparation). Meanwhile, by organizing a seminar at National Taiwan University Hospital in March 2017, we have transferred crucial concepts and techniques regarding how to perform genetic testing for deafness to the Mongolian colleagues. In the future, we plan to strengthen the mutual collaboration by expanding the clinical cohort and upgrading the genetic examination platform using the NGS techniques.

Auditory Outcome of Cochlear Implantation in Adolescent and Adult Patients with Enlarged Vestibular Aqueduct and Biallelic SLC26A4 Mutations / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: Mutations of the SLC26A4 gene cause congenital hearing loss and enlarged vestibular aqueduct (EVA). A considerable proportion of patients with SLC26A4 mutations have significant residual hearing at birth that eventually worsen and become the cause for cochlear implantation (CI) later in their adolescence or adulthood. We analyzed the auditory outcome and prognostic factors of CI in patients with EVA and biallelic SLC26A4 mutations showing progressive early-onset hearing loss, who eventually had implantation in their adolescent or adult periods. SUBJECTS AND METHOD: Sixteen patients with EVA carrying biallelic SLC26A4 mutations who received CI after 12 years of age were included for analysis. The outcome and prognostic factors of CI were analyzed. The postoperative follow-up period ranged from 3 to 48 months. RESULTS: The age at CI ranged from 12 to 44 years. The categories of auditory performance score was significantly improved after CI from 3.1 to 4.9 (p < 0.05). The mean sentence scores improved significantly in the auditory-visual and auditory-only conditions (p < 0.05). The significant prognostic factors were measurable bone conduction thresholds, preoperative residual hearing, recent history of sudden aggravation of hearing loss, and preoperative speech intelligibility rating scores. There was a tendency of lower postoperative sentence scores in the group with homozygous H723R mutation, but statistical significance was not reached. CONCLUSION: Despite the early-onset of hearing loss, significant improvement in auditory performance can be expected after CI in adolescent and adult patients with EVA and biallelic SLC26A4 mutations. Significant prognostic factors should be considered in selecting candidates and preoperative counseling for CI.

The Relationship between the CT Phenotypes of the Inner Ear and Pathogenic Mutations of SLC26A4 in Patients with Sensorineural Hearing Loss / 听力学及言语疾病杂志

Objective To explore the relationship between the CT phenotypes of the inner ear and pathogenic mutations of SLC26A4,and analyze the feasibility of using the method of gene sequence analysis to help CT examination in diagnosing part of patients related to vestibular aqueduct malformation with sensorineural hearing loss.Methods A retrospective review of CT findings relating to 2 705 cases of outpatients was carried out.The inner ear malformations diagnosed by CT were classified according to the methods proposed by Sennaroglu 2010.The DNA sequence of SLC26A4 was analyzed in those patients to explore the relationship between the CT phenotypes and the pathogenic mutations of SLC26A4.Results A total of 826 cases of the inner ear malformations were found in 2 705 cases of patients with sensorineural hearing loss by CT examination.The 446 cases of cochlear malformation consisted of the follow types:5 cases of Michel deformity,12 cases of cochlear aplasia,6 cases of common cavity deformity,34 cases of cochlear hypoplasia (CH-Ⅰ type was 9 cases,CH-Ⅱ type was 8 cases and CH-Ⅲ type was 17 cases),389 cases of cochlear incomplete partition (22 cases of IP-Ⅰ type,352 cases of IP-Ⅱ type,15 cases of IP-Ⅲ type).The 380 cases of non-cochlea malformation consisted of the follow types:340 cases of large vestibular aqueduct,40 cases of simple vestibular/semicircular canal/internal auditory canal malformation,and 1 879 normal cases.The DNA sequence results revealed that 517 cases carried pathogenic mutations (B i-allelic mutations) of SLC26A4,among which 164 cases were homozygous and 353 cases were compound heterozygous.Pathogenic mutations of SLC26A4 detected 100 ％ (517/517) in the group related to vestibular aqueduct malformation and the positive rate was 74.71 ％ (517/692).Conclusion The results suggested that pathogenic mutations of SLC26A4 were closely related to the CT phenotypes of vestibular aqueduct malformation.An analysis of SLC26A4 can help CT examination to diagnose part of patients related to vestibular aqueduct malformation with sensorineural hearing loss.

A Novel Frameshift Mutation of SLC26A4 in a Korean Family With Nonsyndromic Hearing Loss and Enlarged Vestibular Aqueduct

OBJECTIVES: We aimed to identify the causative mutation for siblings in a Korean family with nonsyndromic hearing loss (HL) and enlarged vestibular aqueduct (EVA). The siblings were a 19-year-old female with bilateral profound HL and an 11-year-old male with bilateral moderately severe HL. METHODS: We extracted genomic DNA from blood samples of the siblings with HL, their parents, and 100 controls. We performed mutation analysis for SLC26A4 using direct sequencing. RESULTS: The two siblings were compound heterozygotes with the novel mutation p.I713LfsX8 and the previously described mutation p.H723R. Their parents had heterozygous mono-allelic mutations. Father had p.I713LfsX8 mutation as heterozygous, and mother had p.H723R mutation as heterozygous. However, novel mutation p.I713LfsX8 was not detected in 100 unrelated controls. CONCLUSION: Both mutations identified in this study were located in the sulfate transporter and anti-sigma factor antagonist domain, the core region for membrane targeting of SulP/SLC26 anion transporters, which strongly suggests that failure in membrane trafficking by SLC26A4 is a direct cause of HL in this family. Our study could therefore provide a foundation for further investigations elucidating the SLC26A4-related mechanisms of HL.

Renal intercalated cells and blood pressure regulation

Type B and non-A, non-B intercalated cells are found within the connecting tubule and the cortical collecting duct. Of these cell types, type B intercalated cells are known to mediate Cl⁻ absorption and HCO₃⁻ secretion largely through pendrin-dependent Cl⁻/HCO₃⁻ exchange. This exchange is stimulated by angiotensin II administration and is also stimulated in models of metabolic alkalosis, for instance after aldosterone or NaHCO₃ administration. In some rodent models, pendrin-mediated HCO₃⁻ secretion modulates acid-base balance. However, the role of pendrin in blood pressure regulation is likely of more physiological or clinical significance. Pendrin regulates blood pressure not only by mediating aldosterone-sensitive Cl⁻ absorption, but also by modulating the aldosterone response for epithelial Na⁺ channel (ENaC)-mediated Na⁺ absorption. Pendrin regulates ENaC through changes in open channel of probability, channel surface density, and channels subunit total protein abundance. Thus, aldosterone stimulates ENaC activity through both direct and indirect effects, the latter occurring through its stimulation of pendrin expression and function. Therefore, pendrin contributes to the aldosterone pressor response. Pendrin may also modulate blood pressure in part through its action in the adrenal medulla, where it modulates the release of catecholamines, or through an indirect effect on vascular contractile force. This review describes how aldosterone and angiotensin II-induced signaling regulate pendrin and the contributory role of pendrin in distal nephron function and blood pressure.

Renal intercalated cells and blood pressure regulation

Type B and non-A, non-B intercalated cells are found within the connecting tubule and the cortical collecting duct. Of these cell types, type B intercalated cells are known to mediate Cl⁻ absorption and HCO₃⁻ secretion largely through pendrin-dependent Cl⁻/HCO₃⁻ exchange. This exchange is stimulated by angiotensin II administration and is also stimulated in models of metabolic alkalosis, for instance after aldosterone or NaHCO₃ administration. In some rodent models, pendrin-mediated HCO₃⁻ secretion modulates acid-base balance. However, the role of pendrin in blood pressure regulation is likely of more physiological or clinical significance. Pendrin regulates blood pressure not only by mediating aldosterone-sensitive Cl⁻ absorption, but also by modulating the aldosterone response for epithelial Na⁺ channel (ENaC)-mediated Na⁺ absorption. Pendrin regulates ENaC through changes in open channel of probability, channel surface density, and channels subunit total protein abundance. Thus, aldosterone stimulates ENaC activity through both direct and indirect effects, the latter occurring through its stimulation of pendrin expression and function. Therefore, pendrin contributes to the aldosterone pressor response. Pendrin may also modulate blood pressure in part through its action in the adrenal medulla, where it modulates the release of catecholamines, or through an indirect effect on vascular contractile force. This review describes how aldosterone and angiotensin II-induced signaling regulate pendrin and the contributory role of pendrin in distal nephron function and blood pressure.

Mutation screening of the SLC26A4 gene in a cohort of 192 Chinese patients with congenital hypothyroidism

ABSTRACT Objective Pendred syndrome (PS) is an autosomal recessive disorder characterised by sensorineural hearing loss and thyroid dyshormonogenesis. It is caused by biallelic mutations in the SLC26A4 gene encoding for pendrin. Hypothyroidism in PS can be present from birth and therefore diagnosed by neonatal screening. The aim of this study was to examine the SLC26A4 mutation spectrum and prevalence among congenital hypothyroidism (CH) patients in the Guangxi Zhuang Autonomous Region of China and to establish how frequently PS causes hearing impairment in our patients with CH. Subjects and methods Blood samples were collected from 192 CH patients in Guangxi Zhuang Autonomous Region, China, and genomic DNA was extracted from peripheral blood leukocytes. All exons of the SLC26A4 gene together with their exon-intron boundaries were screened by next-generation sequencing. Patients with SLC26A4 mutations underwent a complete audiological evaluation including otoscopic examination, audiometry and morphological evaluation of the inner ear. Results Next generation sequencing analysis of SLC26A4 in 192 CH patients revealed five different heterozygous variations in eight individuals (8/192, 4%). The prevalence of SLC26A4 mutations was 4% among studied Chinese CH. Three of the eight were diagnosed as enlargement of the vestibular aqueduct (EVA), no PS were found in our 192 CH patients. The mutations included one novel missense variant p.P469S, as well as four known missense variants, namely p.V233L, p.M147I, p.V609G and p.D661E. Of the eight patients identified with SLC26A4 variations in our study, seven patients showed normal size/location of thyroid gland, and one patients showed a decreased size one. Conclusions The prevalence of SLC26A4 pathogenic variants was 4% among studied Chinese patients with CH. Our study expanded the SLC26A4 mutation spectrum, provided the best estimation of SLC26A4 mutation rate for Chinese CH patients and indicated the rarity of PS as a cause of CH.

The analysis of common mutation in deafness-associated gene in 111 neonates who failed to pass newborn hearing screening / 临床儿科杂志

Objective To explore the genetic mutation in neonates who failed to pass hearing screening.Methods A total of 111 cases of neonates who failed to pass hearing screening and were conifrmed sensorineural deafness by auditory brainstem evoked potential (ABR) were randomly selected. The heel blood was collected and DNA was extracted.GJB2, SLC26A4, and 11 mutation hotspots in mitochondria gene12SrRNA were tested. The relationship between degree of hearing loss and gene mutation was analyzed.Results In 111 neonates, mutation in deafness gene were found in 24 cases (21.6%) . Among them 14 cases (12.6%) hadGJB2 gene mutation including 5 cases of 235delC single heterozygous mutation, 5 cases of 235delC, and 1 case each of 299_300delAT compound heterozygous mutation, 235delC homozygous mutation, 299_300delAT single heterozygous mutation, 176_191del16 and 235delC compound heterozygous mutation, and 299_300delAT and 508_511dupAACG compound heterozygous mutation respectively. Ten cases (9.0%) hadSLC26A4 gene mutation including 2 cases of IVS7-2A>G single heterozygous mutation, 3 cases of 1226G>A single heterozygous mutation, 2 cases of 2168A>G single heterozygous mutation, and 3 cases of IVS7-2A>G and 2168A>G compound heterozygous mutation. Mitochondrial gene mutations were not detected. Conclusions Deafness gene mutation is detected in more than 1/5 neonates who failed to pass newborn hearing screening. GJB2 gene mutation is the most commons. The implementation of hotspots deafness gene detection can improve the diagnostic rate of deafness.

Mutations in SLC26A4 Gene and Relevant Phenotype Analysis in Fifty-nine Cases of Enlargement of Vestibular Aqueduct(EVA)Syndrome Children in Guangdong District / 听力学及言语疾病杂志

Objective The molecular etiology of hearing impairment in Guangdong District has not been thor-oughly investigated.SCL26A4 gene mutation and relevant phenotype were analyzed in this study.Methods The coding exons of SLC26A4 were analyzed in 59 EVA cases.Those SLC26A4 gene mutations patients were examined by temporal bone CT.Results Fifty-nine cases were SLC26A4 mutations deafness patients,and 21 cases (35. 59%)and 38 cases (64.41%)patients with SLC26A4 biallelic allele (compound homozygous or heterozygous)and monoallelic gene mutation,including 16 cases of SLC26A4 gene IVS7-2 A> G homozygous mutations,2 cases of 2168A>G homozygous mutations and 3 cases of IVS7-2A>G,2168 A > G compound heterozygous mutations in children with CT showing bilateral enlarged vestibular aqueduct or other types of inner ear malformations.Thirty-one patients were IVS7-2A>G heterozygous for SLC26A4 mutation and seven 2168 A > G heterozygous muta-tion.Four patients with SLC26A4 gene mutations were confirmed to have enlarged vestibular aqueduct with Mondini dysplasia.Two patients with normal phenotype ,and others were enlarged vestibular aqueduct.Conclusion Muta-tions in the SLC26A4 gene with enlarged vestibular aqueduct patients were frequently found in Guangdong District.IVS7-2A>G mutations rate were highest,followed by 2168 A > G.We established the new strategy that detects SLC26A4 mutations prior to the temporal bone CT scan to find enlarged vestibular aqueduct and inner ear malforma-tion patients .

Locus DFNB4 -acueducto vestibular dilatado- comportamiento audio-vestibular / Locus DFNB4 -enlarged vestibular aqueduct- behavior audio vestibular / Locus DFNB4 - aqueduto vestibular dilatada - comportamentoaudio-vestibular

Introducción: el acueducto vestibular dilatado, denominado en la literatura internacional EVA, porEnlarged Vestibular Aqueduct, ha sido reportadopor afectar hasta el 15% de la población pediátrica con hipoacusia neurosensorial. En su génesis compartecon Pendred en el Locus DFNB4, el Gen SLC26A4en el cromosma 7q22-31.1. No se conoce bienel comportamiento y la evolución de esta entidad,debido a la gran variabilidad genotípica y fenotípicaque presenta...

Introduction: Dilated Vestibular Aqueduct, known in the international literature Enlarged Vestibular Aqueduct (EVA) has been reported to affect up to 15% of the pediatric population with hearing loss Sensory Neuro. In its genesis shares with pendred in the locus DFNB4 the SLC26A4 gene in the cromosma 7q22-31.1. It is not well understood and evolution behavior of this entity, due to the great variability genotypic and phenotypic presented...

Introdução: Aqueduto vestibular dilatada conhecido na literatura internacional Enlarged Vestibular Aqueduct (EVA) tem sido relatada a afetar até 15% da população pediátrica com perda auditiva sensorial neuro. Em suas ações genesis com Pendred no Locus DFNB4 o gene SLC26A4 na 7q22-31.1 cromosma. Elenão é bem compreendida e o comportamento de evolução dessa entidade, devido à grande variabilidade genotípica e fenotípica apresentada...

A Mutation Analysis of GJB2 and SLC26A4 Gene in A Chinese Family wi th Non-Syndromi c Deafness / 听力学及言语疾病杂志

Objective To study the molecular pathogenesis of non -syndromic deafness in a Chinese family . Methods Clinical materials and DNA sample were obtained from the non -syndromic family with autosomal reces‐sive deafness .The exons and the flanking splicing sites of GJB2 and SLC26A4 were tested in all family members by PCR and direct sequencing .Results There were four deafness patients in the family ,and three of them had the same clinical phenotypes ,including prelingual profound sensorineural hearing loss and enlarged vestibular ,while the re‐mained one only presented to be prelingual profound sensorineural hearing loss without malformation of temporal bone .One type of GJB2 mutation and 3 different types of SLC26A4 mutations were identified in the family .The proband(Ⅲ -1) ,her sister(Ⅲ -2) ,her mother(Ⅱ -4) and her father(Ⅱ -3) carried different biallelic mutations which were SLC26A4 c .919 -2A > G/p .H723R ,p .Q413R/c .919 -2A > G ,p .Q413R/p .H723R and GJB2 c . 235delC/c .235delC ,respectively .Conclusion Different from most reported deafness families with the same molecu‐lar etiology in each one ,interestingly ,the pathogenies were different among all affected members in this family . They were caused by different biallelic mutations of SLC26A4 or GJB2 .

SLC26A4 Mutations in Korean Population / 대한이비인후과학회지

SLC26A4 mutations are common cause of congenital hearing loss in East Asia. The carrier frequency of SLC26A4 mutations is 1 in 75 in Korean populations. The SLC26A4 mutation spectrum varies according to the population. The most common mutation in Korean is replacement of histidine by arginine at codon 723 followed by exchange of guanine for adenine at the consensus acceptor splice site of intron 7, adenine to guanine change at position +3 transition donor splice site of intron 9, methionine to valine at position 147, and frameshift mutation by insertion T at N-terminal 2. Recent studies analyzed the genotype-phenotype correlation of SLC26A4 mutation and suggested that surface expression ratio of pendrin and residual anion exchange activity was related to the genotype of SLC26A4 mutations. The targeted drug to Korean SLC26A4 mutations would be helpful in preserving hearing in patients with SLC26A4 mutations.

Study the Mutation Screening of GJB3,GJB2,mtDNA,SLC26A4 Gene in Hainan Population with Non-syndromic Hearing Impairment / 现代检验医学杂志

Objective To investigate the mutation screening of the GJB3,GJB2,mtDNA 1555 A>G and SLC26A4 gene in Hainan Pronive population with non-syndromic hearing impairment.Methods PCR were performed with one pair of primer in the coding sequence of GJB3,GJB2,mtDNA 1555 A>G and SLC26A4 gene.Bidirectional sequencing of PCR products was subsequently applied in 429 patients with hearing loss.Results 55 patients gene mutation of 429 patients were found. The point mutation in mtDNA was found in 5 patients (1.1 7%).1 5 5 5 A>G mutation of mtDNA was found in 4 patients. 1494 C>T mutation of mtDNA was found in one patients.GJB2 gene mutation was found in 25 patients (5.83%).235 del C mutation of GJB2 gene was found in 9 patients.235 del C/GJB2 299 del AT mutation was found in two patients.235 del C mutation was found in 10 patients.176 del 16 mutation was found in 4 patients.SLC26A4 mutation was found in 22 patients (5.13%).IVS7-2 A>G mutation of SLC26A4 was found in 4 patients.2168 A>G mutation of SLC26A4 was found in one patient.IVS7-2 A>G mutation was found in 12 patients.2168 A>G mutation was found in 5 patients.538 C>T mutation of GJB3 gene was found in 3 patient.IVS7-2A>G mutation and 2168 A>G muation of SLC26A4 gene was found in 4 of 22 EVA patients.Conclusion GJB2 gene and SLC26A4 gene have revealed responsible genes for Hainan deafness patients.

Carrier frequency of SLC26A4 mutations causing inherited deafness in the Korean population

PURPOSE: The mutation of the SLC26A4 gene is the second most common cause of congenital hearing loss after GJB2 mutations. It has been identified as a major cause of autosomal recessive nonsyndromic hearing loss associated with enlarged vestibular aqueduct and Pendred syndrome. Although most studies of SLC26A4 mutations have dealt with hearing-impaired patients, there are a few reports on the frequency of these mutations in the general population. The purpose of this study was to evaluate the prevalence of SLC26A4 mutations that cause inherited deafness in the general Korean population. MATERIALS AND METHODS: We obtained blood samples from 144 Korean individuals with normal hearing. The samples were subjected to polymerase chain reaction to amplify the entire coding region of the SLC26A4 gene, followed by direct DNA sequencing. RESULTS: Sequencing analysis of this gene identified 5 different variants (c.147C>G, c.225G>C, c.1723A>G, c.2168A>G, and c.2283A>G). The pathogenic mutation c.2168A>G (p.H723R) was identified in 1.39% (2/144) of the subjects with normal hearing. CONCLUSION: These data provide information about carrier frequency for SLC26A4 mutation-associated hearing loss and have important implications for genetic diagnostic testing for inherited deafness in the Korean population.