GJB2 gene mutations in newborns with non-syndromic hearing impairment in Northern China

Mutations in GJB2 account for the majority of recessive forms of prelingual hearing loss. However, in most previous studies it was not possible to distinguish between congenital (present at birth) and non-congenital prelingual hearing loss. In the present study, the frequency of GJB2 alleles in 20 newborns with bilateral severe-to-profound non-syndromic hearing impairment (NSHI) who were found at birth through newborn hearing screening and clinical examination is reported. PCR was used to amplify the coding region of GJB2 gene followed by sequencing analyses. Fifty volunteers with normal hearing were included as controls. Results showed that three cases were 235delC/235delC homozygotes; one was 235delC/605ins46 compound heterozygotes, 605ins46 mutation was a novel mutation reported in the Chinese population; another was 235delC/299-300delAT compound heterozygotes. 25% (5/20) of the deafness in newborns studied was caused by GJB2 gene mutations. The frequency of 235delC allele carrier in patients and in control group was 22.5% and 1%, respectively. One case was identified as being a 235delC heterozygote without other mutations detected. Besides, multiple polymorphisms such as V27I, V37I, E114G, T123N were also detected. In conclusion, GJB2 analysis is an important test that identifies a major cause of newborns with bilateral severe-to-profound NSHI screened by universal newborn hearing screening in Northern China. The most common pathologic mutation of GJB2 in studied cases was 235delC. Molecular analysis and genetic counseling will be extremely important for congenital deafness present at birth.     

散发感音神经性聋患者中GJB2基因突变检测的临床意义

目的探讨散发感音神经性聋患者中GJB2基因突变检测的临床指导意义.方法运用聚合酶链反应对解放军总医院听力诊断中心收集的242例散发感音神经性聋患者(135例语前聋患者,107例语后聋患者)的GJB2基因编码区进行扩增,扩增产物纯化后直接测序分析.结果 135例语前聋患者中GJB2基因致病突变的复合杂合和纯合个体有26例,占语前聋个体的19.26%;107例语后聋患者中未发现复合杂合和纯合致病突变,仅发现3例235delC杂合突变携带者、1例176del16杂合突变携带者.结论语前聋者GJB2基因致病突变阳性率明显高于语后聋患者,语前聋患者常规进行GJB2基因检测可从基因水平明确诊断,并为耳聋患者提供重要遗传信息.     

Successful cochlear implantation in prelingual profound deafness resulting from the common 233delC mutation of the GJB2 gene in the Japanese

OBJECTIVES: Recently, we identified three novel mutations of the GJB2 gene in Japanese families with autosomal-recessive non-syndromic deafness.1 Seven of 11 mutated chromosomes (63.6%) contained a 233delC allele, suggesting that the 233delC mutation is the most common mutation of the GJB2 gene in the Japanese population. After it was recognized that cochlear implantation (CI) is of benefit to children with prelingual deafness, we have had a number of prelingual pediatric CI patients. Because children carrying the homozygous 233delC mutation show bilateral prelingual profound deafness, they could be enrolled in the CI program at Osaka University Graduate School of Medicine. The purposes of this study were 1) to analyze the occurrence of the GJB2 mutations in our 15 prelingual pediatric CI patients in whom the cause of non-syndromic deafness was unknown, and 2) to evaluate the auditory function and postoperative speech perception with CI of those GJB2-related deaf subjects. STUDY DESIGN: Retrospective analysis. METHODS: Mutation analysis of the GJB2 gene by direct sequencing was performed with genomic DNA from 15 children born profoundly deaf as a result of unknown causes and implanted with CI. Intraoperative electrically evoked auditory brainstem response (EABR) and intra-/postoperative EAP were measured. The speech perception was evaluated with Infants and Toddlers Meaningful Auditory Integration Scale (IT-MAIS). RESULTS AND CONCLUSIONS: We identified 4 CI patients (26.7%) out of 15 children carrying the homozygous 233delC mutation. Intra- and postoperative evaluation of the auditory system revealed almost intact cochlear and retrocochlear auditory function in these 4 patients. Postoperative auditory testing indicates that their speech perception had become significantly higher in comparison with that of other prelingual CI patients. These results suggest that prelingual deaf children carrying the homozygous 233delC mutation of the GJB2 gene can benefit from CI.     

High-throughput screening for GJB2 mutations--its clinical application to genetic testing in prelingual deafness screening for GJB2 mutations

OBJECTIVES: Mutations in connexin26 (GJB2) are one of the most frequent causes of prelingual hearing impairment. Several different types of one-base deletions in exon2 were the most common type of GJB2 mutation regardless of ethnicity, including 35delG in American-European populations, 235delC in Japanese population and 167delT in Ashkenazi Jewish population. Various types of one-base substitutions were also considered to be causative mutations of GJB2 associated hearing impairment. This article describes a rapid and high-throughput screening procedure for the detection of one-base deletion/substitution in GJB2 with less invasive sampling procedure in the implication for the clinical application. METHODS: 53 hearing-impaired children and 50 healthy controls were admitted to take part in this study program. DNA samples obtained from buccal swab were used to amplify the exon2 of GJB2, and single run with an automated sequencer was used to identify the one-base deletion. Single-base substitutions were also screened by primer-extension procedure with dye terminators. The presence of both types of mutations was confirmed by direct sequence of the GJB2 exon2. RESULTS: Two of 50 controls (4%) included one-base deletion in GJB2 as heterozygote. 14 of 53 hearing impaired cases (26.4%) contained deletion in GJB2 either as homozygote (five cases) or heterozygote (nine cases) form. Sequencing analysis of whole exon2 of GJB2 identified all these deletions as 235delC. Primer-extension analysis revealed additional mutations with single base substitutions in three cases with compound heterozygote with 235delC. CONCLUSIONS: Rapid screening procedure of GJB2 can be potentially useful for the identification of prelingual deafness.     

APPLICATION OF GENETIC DEAFNESS GENE CHIP FOR DETECTION OF GENE MUTATION OF DEAFNESS IN PREGNANT WOMEN

Objective The study is to identify the carrier rate of common deafness mutation in Chinese pregnant women via detecting deafness gene mutations with gene chip. Methods The pregnant women in obstetric clinic without hearing impairment and hearing disorders family history were selected. The informed consent was signed. Peripheral blood was taken to extract genom- ic DNA. Application of genetic deafness gene chip for detecting 9 mutational hot spot of the most common 4 Chinese deafness genes, namely GJB2 （35delG, 176del16bp, 235delC, 299delAT）, GJB3 （C538T） ,SLC26A4 （ IVS72A〉G, A2168G） and mito- chondrial DNA 12S rRNA （A1555G, C1494T） . Further genetic testing were provided to the spouses and newborns of the screened carriers. Results Peripheral blood of 430 pregnant women were detected, detection of deafness gene mutation carri- ers in 24 cases（4.2%）, including 13 cases of the GJB2 heterozygous mutation, 3 cases of SLC26A4 heterozygous mutation, 1 cases of GJB3 heterozygous mutation, and 1 case of mitochondrial 12S rRNA mutation. 18 spouses and 17 newborns took further genetic tests, and 6 newborns inherited the mutation from their mother. Conclusion The common deafness genes muta- tion has a high carrier rate in pregnant women group, 235delC and IVS7-2A〉G heterozygous mutations are common.     

GJB2, SLC26A4 and mitochondrial DNA A1555G mutations in prelingual deafness in Northern Chinese subjects

CONCLUSION: This genetic epidemiological study demonstrated that 26.65% of the prelingual deafness in Northern Chinese patients can be detected at younger ages by genetic testing of three common hearing loss genes (GJB2, SLC26A4 and mtDNA A1555G), and thus, early intervention measures could be undertaken to help them in language acquisition. OBJECTIVES: The GJB2, SLC26A4 and mtDNA A1555G mutations are the prevalent causes of prelingual deafness worldwide. Numerous studies have revealed that the forms and frequencies of the mutations in the three genes are largely dependent on the ethnic or geographic origins. Hence, this study aimed to characterize the mutation profiles of the three genes in prelingual deafness in Northern Chinese patients. SUBECTS AND METHODS: An investigation of 514 patients with prelingual deafness and 117 controls with normal hearing was conducted. Bidirectional sequencing (or enzyme digestion) was applied to identify sequence variations. RESULTS: This study revealed that 26.65% patients had two mutated alleles (homozygote or compound heterozygote) of GJB2 (9.14%) or SLC26A4 (8.95%) and/or an mtDNA A1555G (8.56%) mutation. In detail, 19.26% patients carried GJB2 mutations including 10.12% single mutant carriers. 235delC was the most common type, making up 69.18% of all mutants for GJB2. The mutant carrier rate for SLC26A4 was 15.2%, including 6.23% single mutant carriers. The two most common types (IVS7-2A > G and H723R) accounted for 51.61% and 33.06% mutations, respectively. Forty-five patients had mtDNA A1555G, giving a frequency of 8.75%. In the control group with normal hearing, 2.56%, 1.71% and 0% of the subjects carried a single mutant for GJB2, SLC26A4 and mtDNA A1555G, respectively.     

扬州市特教学校耳聋学生常见耳聋突变基因调查报告

目的:调查扬州地区非综合征性聋患儿常见耳聋突变基因的发病情况。方法:选择扬州市特教学校90例中、重度非综合征性聋学生为研究对象。在苏北人民医院医学检测中心利用耳聋基因芯片诊断试剂盒筛查常见的耳聋相关基因的9个热点突变,包括GJB2(35delG、176del16、235delC及299delAT),GJB3(538C>T),SLC26A4(IVS7-2A>G、2168A>G)和mtDNA 12SrRNA(A>G、1494C>T)。结果:在90例耳聋患者中,基因芯片方法共检出携带致聋基因突变64例(71.1%)。其中,GJB2基因突变40例(44.4%),包括235delC纯合突变20例(22.2%),235delC单杂合突变4例(4.4%),235delC和299delAT复合杂合突变2例(2.2%);299de-lAT单杂合突变2例(2.2%),299delAT纯合突变2例(2.2%);176del16单杂合突变2例(2.2%),176del16纯合突变2例(2.2%),176del16和235delC复合杂合突变6例(6.7%)。SLC26A4基因突变22例(24.4%),包括IVS7-2A>G纯合突变2例,IVS7-2A>G和2168A>G复合杂合突变2例(2.2%),IVS7-2A>G单杂合突变18例(20.0%);mtDNA 12SrRNA A>G纯合突变2例(2.2%);未检出GJB3基因突变。结论:应用基因诊断技术可以在耳聋患者病因调查中进行快速筛查诊断,值得推广应用。     

非综合征型感音神经性聋儿GJB2基因突变分析

目的 对散发聋病患儿进行GJB2基因突变检测,探究其在遗传性聋临床工作中的意义.方法 收集门诊139例散发非综合征型感音神经性聋患儿及150例听力正常个体的外周血DNA样本共289例,采用聚合酶链反应分析方法扩增GJB2基因片断进行序列分析.结果 139例病患组中发现GJB2基因突变31例,占22.30%.其中235d...     

散发性耳聋GJB2基因突变分析

目的 通过分析内蒙古鄂尔多斯和呼和浩特地区散发性耳聋患者GJB2 235delC点突变,以探讨散发性耳聋患者的分子病因学。方法 对131例(汉族92例,蒙古族39例) 散发性耳聋患者进行耳聋病因学问卷调查、纯音听阈及声导抗测试。聚合酶链反应(polymerase chain reaction PCR)扩增目的片段并用限制性内切酶对其进行GJB2 235delC基因突变检测,对酶切检测结果呈阳性的样本用直接测序法进行验证。对50例健康中国人和100例健康加拿大白种人行限制性内切酶GJB2 235delC点突变检测,作为阴性对照。结果 131例散发性耳聋患者全部为感音神经性聋。在该群体中4例(汉族3例,蒙古族1例)存在GJB2 235delC纯合性突变;3例(汉族2例,蒙古族1例)存在GJB2 235delC杂合性突变。50例健康中国人对照组中检测出1例GJB2 235delC点突变携带者,100例健康加拿大白种人中未检测到GJB2 235delC点突变。结论 GJB2 235delC点突变是中国人散发性感音神经性耳聋的分子病因学之一。内蒙古地区汉族、蒙古族GJB2 235delC突变频率无明显差异,对GJB2 235delC点突变的基因筛查可以明确一些散发性耳聋患者的病因,从而对基因突变引起的散发性耳聋的早期诊断、遗传咨询及防聋治聋起到重要作用。     

Connexin 26基因233delC突变与中国人先天性耳聋的研究

目的 :Connexin2 6基因突变是引起常染色体隐性遗传 DFNB1和常染色体显性遗传 DFNA3的遗传基础 ,其中的 35 del G的突变在欧美人 DFNB1耳聋患者中的检出率为 70～ 80 % ,但在中国耳聋人群中未检到该点突变。本文旨在筛选中国人耳聋相关的 Connexin2 6基因的突变热点。方法 :采用 PCR- RFL P筛选 2 19例不同耳聋类型的患者和 5 0例听力正常人的 Connexin 2 6基因 2 33del C的突变 (2 1.5 % )。结果 :2 19例耳聋患者中共发现了 47例 Connexin 2 6基因2 33del C的突变 (2 1.5 % )。在先天性耳聋患者中 2 33del C的突变率为 33% ,遗传性语前聋患者为 2 6 .7%。 5 0例药物性致聋的患者有 10例发生突变。遗传性及散发性进行性感音神经性耳聋和听力正常人未检测到 2 33delc突变。结论 :Connexin2 6基因 2 33del C突变在中国先天性耳聋人群中发生频率较高 ,与欧美人不同。我们的结果表明 ,Connexin2 6基因异常导致耳聋的突变热点具有种族特异性     

Cordblood-Based High-Throughput Screening for Deafness Gene of 646 Newborns in Jinan Area of China

Objectives

Infants with slight/mild or late-onset hearing impairment might be missed in universal newborn hearing screening (UNHS). We identified the mutation hot spot of common deaf gene in the newborns in Jinan area population by screening the mutation spot with neonate cord blood, in order to make clear whether the neonate cord blood for screening is feasible.

Methods

Six hundred and forty-six newborns were subjected to both UNHS and genetic screening for deafness by using neonate cord blood. The newborn genetic screening targeted four deafness-associated genes, which were commonly found in the Chinese population including gap junction beta-2 protein (GJB2), gap junction beta-3 protein (GJB3), solute carrier family 26 member 4 (SLC26A4), and mtDNA 12S rRNA. The most common 20 spot mutations in 4 deaf genes were detected by MassARRAY iPLEX platform and mitochondrial 12S rRNA A1555G and C1494T mutations were sequenced using Sanger sequencing.

Results

Among the 646 newborns, 635 cases passed the UNHS and the other 11 cases (1.7%) did not. Of the 11 failures, two cases were found to carry homozygous GJB2 p.R143W pathogenic mutation, one case was found to have heterozygous GJB2 235delC mutation, and another one case carried heterozygous GJB3 p.R180X pathogenic mutation. Six hundred and thirty-five babies passed the newborn hearing screening, in which 25 babies were identified to carry pathogenic mutations, including 12 heterozygotes (1.9%) for GJB2 235delC, eight heterozygotes (1.3%) for SLC26A4 IVS7-2A>G, one heterozygote (0.2%) for p.R409H, two homozygotes (0.3%) for m.1494C>T, and two homozygotes (0.3%) for m.1555A>G.

Conclusion

Newborn genetic screening through the umbilical cord blood for common deafness-associated mutations may identify carriers sensitive to aminoglycoside antibiotic, and can effectively prevent or delay hearing loss occurs.     

Prevalence of GJB2 mutations in prelingual deafness in the Greek population

OBJECTIVE: Mutations in the gene encoding the gap junction protein connexin 26 (GJB2) have been shown as a major contributor to prelingual, sensorineural, nonsyndromic, recessive deafness. One specific mutation, 35delG, has accounted for the majority of the mutations detected in the GJB2 gene in Caucasian populations. The aim of our study was to determine the prevalence and spectrum of GJB2 mutations in prelingual deafness in the Greek population. METHODS: In a collaboration with the major referral centers for childhood deafness in Greece, patients were examined by an extensive questionnaire to exclude syndromic forms and environmental causes of deafness and by allele-specific polymerase chain reaction (PCR) for the detection of the 35delG mutation. Patients heterozygous for the 35delG mutation were further analyzed by direct genomic sequencing of the coding region of the GJB2 gene. RESULTS: The 35delG mutation was found in 42.2% of the chromosomes in 45 familial cases of prelingual, nonsyndromic deafness (18 homozygotes and 2 heterozygotes) and in 30.6% of the chromosomes in 165 sporadic cases (45 homozygotes and 11 heterozygotes). Direct genomic sequencing in heterozygous patients revealed the L90P (2 alleles), W24X (2 alleles), R184P (2 alleles), and 291insA (1 allele) mutations. CONCLUSION: Mutations in the GJB2 gene are responsible for about one third of prelingual, sensorineural, nonsyndromic deafness in the Greek population, and allele-specific PCR is an easy screening method for the common 35delG mutation.     

gjb2 mutation spectrum in inner mongolia and its comparison with other asian populations

Mutations in the GJB2 gene are the most frequently found mutations in patients with nonsyndromic hearing impairment. However, the mutation spectrum and prevalence of mutations vary among different ethnic groups. Every year, 30,000 babies are born with congenital hearing impairment in China. In order to provide appro-pilate genetic testing and counseling to the family, we investigated the molecular etiology of nonsyndromic deafness in 135 unrelated school children attending Chifeng Municipal Special Education School in Inner Mongolia, China. The coding exon of the GJB2 gene was PCR amplified and sequenced. In addition, the 12S rRNA gene and tRNAser UCN of mitochondrial genome were screened for mutations responsible for hearing impairment. Sixty four GJB2 mu-tant alleles, including 60 confirmed pathogenic alleles and 4 unclassified variants, were identified in 31.1% (42/135) of the subjects. Twenty two subjects carried two pathogenic mutations and 20 subjects carried one mutant allele, in-cluding one subject with one autosomal dominant mutation. The 235delC was the most common mutation account-ing for 65.6%(42/64) GJB2 mutant alleles. When compared to other Asian populations, our subject cohort had high-er frequency of 235delC mutation than the Japanese population. The GJB2 mutant alleles account for 23.7% (64/270) of all chromosomes responsible for nonsyndromic heating impairment. Testing of the 4 most prevalent deleterious frame shift mutations(235delC, 299_300delAT, 176191_del16, and 560_605ins46) in this cohort detect-ed 90% of all GJB2 mutant alleles. These results demonstrate that effective genetic testing of the GJB2 gene for pa-tients and families with nonsyndromic hearing impairment is possible in the Chinese population. Since the most common 309kb GJB6 deletion is not detected and only one 1555 A>G mutation in mitochondrial DNA is detected in our patients, investigation of mutations in other nuclear genes and/or environmental factors responsible for non-syndromic heating impairment in the Chinese population is necessary.     

湖北地区306例极重度聋患儿基因芯片筛查分析

目的：通过检测湖北地区极重度感音神经性聋患儿常见耳聋基因突变情况,分析该人群的分子病因学特点,为临床耳聋防治和遗传咨询提供参考。方法：收集306例湖北地区极重度感音神经性聋患儿,抽取外周血,提取DNA,应用遗传性耳聋基因芯片检测GJB2、GJB3、SLC26A4和线粒体12SrRNA4个基因的9个突变热点。对所有携带SLC26A4基因突变患者进行颞骨CT扫描。结果：306名患儿中,132例（43．14％）检出携带不同基因突变,其中有2例携带双基因突变。GJB2基因突变检出率为29．41％（90／306）,SLC26A4基因突变检出率为13．72％（42／306）,线粒体12SrRNA基因突变检出率为O．65％（2／306）。本组患者未检出GJB3基因突变。36例携带SLC26A4基因突变者颞骨CT扫描显示前庭水管扩大。结论：GJB2基因和SLC26A4基因是本组患儿最主要的致聋基因,其中235delC突变为最常见的突变位点,其次为1VS7—2A〉G突变。筛查SLC26A4基因常见突变有助于大前庭水管综合征的诊断。     

Prelingual nonsyndromic hearing loss in Greece. Molecular and clinical findings

Mutations in the gene encoding the gap-junction protein connexin 26 (GJB2) on chromosome 13q11 have been shown as a major contributor to prelingual, sensorineural, nonsyndromic deafness. One specific mutation, 35delG, has accounted for the majority of the mutations detected in the GJB2 gene in Caucasian populations and is one of the most frequent disease mutations identified so far with highest carrier frequency of 3,5% in the Greek population. In a collaboration with the major referral centers for childhood deafness in Greece, patients were examined by an extensive questionnaire to exclude syndromic forms and environmental causes of deafness and by allele-specific PCR for the detection of the 35delG mutation. The 35delG mutation was found in 32.1% of the alleles in 173 unrelated cases of prelingual deafness: 50 homozygotes and 11 heterozygotes. Individuals heterozygous for the 35delG mutation were further analyzed by direct genomic sequencing of the coding region of the GJB2 gene, which revealed R184P and 486insT mutations in single alleles. We conclude that the 35delG GJB2 mutation is responsible for one third of prelingual, sensorineural deafness in Greece, which is higher than the usually quoted 20% for Caucasian populations.     

广西地区222例感音神经性聋患者常见耳聋基因筛查结果分析

目的：分析广西地区222例感音神经性聋患者常见耳聋基因的突变特点,为临床防聋及治聋提供参考。方法采用晶芯.十五项遗传性聋基因检测试剂盒（微阵列芯片法）对广西地区222例感音神经性聋患者进行常见的4种耳聋基因的15个突变位点检测：GJB2（35del G、235delC、176del16、299del AT ）、SLC26A4（2168A＞G、IVS7－2A＞G、1174A＞T、1226G＞A、1229C＞T、1975G＞C、2027T＞A、IVS15＋5 G＞A）、线粒体DNA12SrRNA （1494C＞T、1555A＞G）和GJB3（538C＞T）,对未确诊的阳性结果进行基因全序列分析。结果222例患者中23例（10．36％,23／222）被检测出耳聋基因突变,其中,GJB2235delC 纯合突变3例（1．35％）,杂合突变8例（3．60％）,GJB235delG杂合突变2例（0．90％）,GJB2235delC／109A＞G 复合杂合突变2例（0．90％）;SLC26A4 IVS7－2 A＞G杂合突变2例（0．90％）,SLC26A41229C＞T纯合突变2例（0．90％）,IVS7－2A＞G／IVS11＋47T＞C／1548insC复合杂合突变2例（0．90％）;GJB3538C＞T 杂合突变1例（0．45％）;线粒体DNA12SrRNA 1555A＞G异质突变1例（0．45％）;1例（0．45％）同时携带GJB2235delC杂合突变及SLC26A41226G＞A杂合突变。结论本组广西地区感音神经性聋患者耳聋基因突变率低于全国水平,主要以 GJB2基因突变为主,其次是SLC26 A4基因突变。     

蒙古族耳聋患者中常见致聋基因突变分析

目的探讨常见耳聋基因GJB2、线粒体DNA12SrRNA基因SLC26A4在蒙古族耳聋患者中的突变特点。方法收集64例蒙古族耳聋先证者进行GJB2、SLC26A4、mtDNA12SRNA三种常见的耳聋致病基因分子流行病学调查和基因型分析。结果 2例GJB2基因纯合突变均为235delC/235delC,复合杂合突变2例,杂合突变1例;SLC26A4基因纯合突变4例均为919-2A>G/919-2A>G,复合杂合突变4例,杂合突变7例。线粒体DNA12SrRNA1494和1555位点未检测到突变。64例蒙古族耳聋先证者GJB2、SLC26A4和线粒体DNA12SrRNA三种基因突变携带率分别为7.81%(5/64)、23.44%(15/64)和0。突变率最高的基因为SLC26A4(75%,15/20),而在突变基因中GJB2基因占25%(5/20)。结论本组蒙古族非综合征型聋患者三种常见聋病基因中突变率最高的基因是SLC26A4,其次为GJB2基因,而线粒体DNA12SrRNA基因未检出突变。     

新疆地区非综合征型聋患者耳聋相关基因检测结果分析

目的探讨新疆地区非综合征型耳聋患者常见耳聋基因突变热点,为该地区更好地开展耳聋基因诊断工作提供参考。方法通过问卷、健康体检及听力检测筛选出新疆地区399例非综合征型耳聋患者为研究对象,所有受检者均采集外周血并提取基因组DNA,应用分子生物学方法检测GJB2(c.35delG,c.167delT,c.176_191del16,c.235delC,c.299_300delAT)、SLC26A4(c.281C>T,c.589G>A,c.IVS7-2A>G,c.1174A>T,c.1226G>A,c.1229C>T,c.IVS15+5G>A,c.1975G>C,c.2027T>A,c.2162C>T,c.2168A>G)、mtDNA12SrRNA(c.1494C>T,c.1555A>G,c.1585A>G,c.1047A>G,c.1095T>C,c.960_961insC/c.961delT)基因22个位点突变情况。结果399例非综合征型耳聋患者中GJB2、SLC26A4、mtDAN12SrRNA基因的突变携带率分别为11.28%(45/399)、10.78%(43/399)、4.76%(19/399),致病突变率分别为6.52%(26/399)、3.76%(15/399)、3.51%(14/399)。c.235delC和c.IVS7-2A>G在汉族(16/92,11/92)和维吾尔族(18/273,10/273)中都是突变热点,在汉族中c.2168A>G也呈现突变热点趋势,而在维吾尔族中c.1174A>T、c.35delG、c.2027T>A等多个位点都呈现出突变热点的趋势。在汉族c.235delC(χ^2=9.498,P=0.002)、c.IVS7-2A>G(χ^2=8.729,P=0.003)和c.2168 A>G(P=0.001)突变率高于维吾尔族。结论GJB2、SLC26A4、mtDNA12SrRNA为新疆非综合征型耳聋常见致病基因,c.235delC和c.IVS7-2A>G是汉族和维吾尔族突变热点,汉族中c.235delC、c.IVS7-2A>G和c.2168A>G突变率显著高于维吾尔族。     

长沙市新生儿听力和聋病易感基因联合筛查的临床分析

目的 探讨长沙市新生儿听力和聋病易感基因联合筛查的可行性和必要性。方法 对2017年5—12月出生长沙市妇幼保健院的5 526例新生儿进行听力与聋病易感基因的同步筛查。对未通过复筛和（或）聋病易感基因筛查的新生儿进行电话随访,指导其在3月龄内进行听力学和遗传学诊断及干预。结果 5 526例新生儿接受了听力与聋病易感基因的同步筛查,聋病易感基因筛查未通过率4.23%（234/5 526）,听力初筛未通过率12.07%（667/5 526）,听力初筛未通过的新生儿中聋病易感基因筛查未通过率15.44%（103/667）高于听力筛查通过者2.69%（131/4 859）（P<0.000）。234例耳聋基因突变中,GJB2 235delC纯合突变4例,SLC26A4 2168 A>G纯合突变1例。GJB2基因突变最常见2.55%（141/5 526）,其次是SLC26A4基因突变1.21%（67/5 526）,MTRNR1基因突变0.36%（20/5 526）,GJB3基因突变0.11%（6/5 526）。最常见的突变为GJB2 235del C杂合突变和SLC26A4 IVS 7-2A>G杂合突变。对107例听力复筛未通过的患儿在3月龄时进行了听力学诊断,确诊感音神经性听力损失14例（23耳）,随访8耳佩戴助听器,4耳人工耳蜗植入。结论 聋病易感基因和听力筛查未通过的互为随访的高危人群,新生儿听力和聋病易感基因联合筛查可行性强,相互裨益,是目前最佳的防聋筛查模式。     

prevalence of the gjb2 mutations in deafness patients of different ethnic origins in xinjiang

Objective To investigate GJB2 mutation prevalences in the Uigur and Han ethnic groups in Xinjiang, China, and determine the relationship between ethnicity and GJB2 gene mutations. Methods Information regarding ethnicity of patients' families was obtained through medical records review and/or patient interview. Blood samples were collected from 61 Uigurs and 66 Hans for direct sequencing of the coding region and intron/exon boundaries of the GBJ2 gene. Results Carrier frequency of GJB2 mutations was similar between the Uigur and Han subjects. The GJB2 35delG mutation was seen only in Uigur patients with hearing loss, whereas the 235delC mutation was identified in both Uigur and Han patients. The allelic Frequency of 35delG mutation was 7.4% (9/122) in Uigur deaf students, but none in Han deaf students (0/128) and Uigur controls (0/196). The allelic frequency of GJB2 235delC mutation in Uigur and Han deaf students was 5.7% and 9.8%, and that of 299-300delAT mutation was 0.8% and 5.5%, respectively. V27I and E114G were the most frequent types of polymorphism. Conclusion We found an Asian-specific GJB2 diversity among Uigurs, and comparable GJB2 contribution to deafness in Uigur and Han patients. The high carrier frequency of 35delG in Uigurs (11.5%) is probably defined by gene drift/founder effect in a particular group. Even though GJB2 mutations have been widely reported in the literature, this discussion represents the first report of GJB2 mutations in Chinese multi-ethnic populations.