非综合征性聋常见致聋基因及其基因诊断

非综合征性聋占遗传性聋的70％,至今已有60余个非综合征性聋基因被克隆.随着耳聋基因研究的迅速发展及基因检测技术的不断进步,耳聋基因诊断将广泛应用于耳聋病因学检查和预防性筛查中,有助于耳聋更准确的诊断和更恰当的遗传咨询.     

云南3所特教学校聋生临床资料分析

目的对云南3所特殊教育学校聋生人群进行系统性的耳聋临床资料分析,为开展耳聋基因的分子流行病学研究提供参考依据。方法了解聋生详细的耳聋病史;进行全身及耳鼻咽喉常规检查;进行纯音听阂测试及声导抗测试,了解聋生双耳听功能和中耳功能状况。结果聋生耳聋前有耳毒性药物用药史者占8．2％,有家族史者占19．5％,综合征性耳聋占5．3％,耳聋病因不明者亦占较大比例;汉族与非汉族聋生在综合征性耳聋和聋前用药史方面无显著差异,汉族聋生有家族史的比例高于非汉族聋生。结论云南省聋生可能的致聋原因有遗传性聋、药物性聋,但大部分聋生病因不明,尚需借助分子生物学理论和技术,从基因水平进行耳聋病因学的深入研究。。     

非综合征型聋相关基因研究进展

非综合征型聋是由遗传因素引起的最常见的感音神经性聋。深入了解耳聋分子病因学的特点,不仅有助于我们对耳聋患者进行病因诊断、遗传咨询、产前诊断和新生儿听力筛查,还可以及时干预和治疗,为防聋治聋提供帮助。目前人类研究发现的致聋基因已有百余种,中国最常见的致聋基因为GJB2、SLC26A4、线粒体DNA12S rRNA和GJB3。本文对非综合征型聋相关基因的研究进展予以综述。     

非综合征性聋突变热点的流行病学分析

目的:了解耳聋基因突变热点在中国患者中的分布特征,以建立针对突变热点的区域性基因筛查方案。方法:运用万方和Pubmed等检索2006-2011年上半年国内报道的中国各地区人群耳聋相关基因GJB2、SLC26A4、mtDNA突变流行病学文献,对文献中的样本量、样本特征、地域分布、突变频率等多个因素进行统计分析。结果:检索到相关文献46篇,纳入该统计分析42篇,研究区域涉及中国20个省、市、自治区和直辖市,调查人群均为非综合征型感音神经性聋患者;样本总量18 094例,GJB2 235delC突变频率为16.34%,GJB2299-300delAT突变频率为4.75%;SLC26A4IVS7-2A>G突变频率为12.60%,SLC26A4 2168A>G突变频率为2.32%;mtDNA 1555A>G突变频率为5.21%,mtDNA 1494C>T突变频率为1.11%。6个耳聋基因突变热点在非综合征性聋中总的突变频率约为42.00%,不同区域间差异有统计学意义(P<0.05)。结论:中国耳聋突变频率的流行病学调查统计显示上述6个位点为中国人群非综合征性聋突变热点,可根据各地区具体突变特点从中选择适合的位点进行基因筛查。     

甘肃省盲聋哑学校283名聋哑学生的病因分析

目的 在我国甘肃省聋哑人群中进行系统性的耳聋病因研究，即耳聋病因的临床流行病学分析，明确不同致聋因素所占比例，为将来开展耳聋易感基因的分子流行病学研究，寻找致病根源，有效开展耳聋预防和干预工作提供参考依据。方法 填写问卷式调查表、电话家访，了解聋哑学生详细的耳聋病史；声导抗检查和听性脑干反应测试，了解聋哑学生双耳听功能状况；经全身及耳鼻咽喉常规检查，将表现出综合征性耳聋常见特殊体征的聋哑学生排除在本研究对象选择范围外。结果 临床流行病学的调查结果显示，药物性耳聋位居病因之首．并主要与使用庆大霉素和链霉素有关；其次为家族遗传、近亲婚配、母孕期不良因素致聋等；耳聋病因不明者亦占较大的比例。结论 通过临床流行病学初步调查分析了甘肃省聋哑人的致聋原因，今后尚需借助分子生物学理论和技术，从基因水平进行耳聋病因学的深入研究。     

一母系遗传氨基糖苷类抗生素致聋家系线粒体DNA A1555G突变检测

目的 应用耳聋基因芯片对一母系遗传氨基糖苷类抗生素致聋家系和散发的非综合征性耳聋患者进行分子病因学研究.方法 采集一母系遗传耳聋家系2代共12人和散发非综合征耳聋患者68人的外周静脉血,从白细胞中提取DNA,聚合酶链反应(polymerase chain reaction,PCR)扩增,应用耳聋基因芯片检测中国人常见的药物性耳聋相关基因--线粒体DNA A1555G突变.结果 家系中有7份样品存在线粒体DNA 12S rRNA 1555位点A→G的突变.其余样品为A1555G点突变阴性;而散发的耳聋患者中未检测出一例携带此突变.结论 线粒体DNA A1555G点突变是导致该家系致聋的主要因素之一,具有母系遗传耳聋特点.     

中国西北地区801例聋哑学生临床流行病学病因分析

目的在中国西北地区聋哑人群中进行耳聋的临床病因学分析，明确不同致聋因素在该地区耳聋患者中的分布特点和流行规律。方法对中国西北地区5所聋哑学校的801例聋哑学生，采用问卷式调查及电话家访的方式采集病史；由专科医生进行全身及耳部检查排除综合征型患者；由专业测听师进行听力学检测，判断听力损失程度。结果801例聋哑学生中有326例为药物性聋，占40．69％（326／801），其中氨基糖苷类抗生素（AmAn）致聋占药物性聋的86．5％（282／326）；家族遗传性聋85例，占10．61％（85／801）；母孕期感染、新生儿疾患及婴幼儿期疾病引起的耳聋190例，占23．72％（190／801）。结论药物性聋是导致该地区耳聋发病的主要原因，其次为家族遗传性聋；新生儿和婴幼儿疾病也是导致该地区耳聋的主要因素。     

广西壮族135例非综合征性聋常见致病基因的研究

目的分析研究广西地区壮族人群135例非综合征性聋常见致聋基因的突变特点,为防聋治聋工作提供参考。方法采用遗传性耳聋基因芯片试剂盒对广西地区壮族人群135例以及汉族人群44例非综合征性聋患者基因组DNA的4个常见致聋基因的15个突变位点进行检测,比较壮、汉族人群常见耳聋基因突变率的差异性。结果 135例壮族人群非综合征性聋患者常见致聋基因突变率为11.11%(15/135);其中GJB2 235del C纯合突变4例(2.96%),单杂合突变3例(2.22%);GJB2 235del C/109 A>G复合杂合突变2例(1.48%);SLC26A4 IVS7-2 A>G杂合突变1例(0.74%),IVS7-2A>G/IVS11+47T﹥C/1548ins C复合杂合突变2例(1.48%);GJB3 538C>T单杂合突变1例(0.74%),线粒体12S r RNA 1555 A>G异质突变1例(0.74%),GJB2 235 del C杂合突变合并SLC26A4 1226 G>A杂合突变1例(0.74%)。44例汉族非综合征性聋患者常见致聋基因突变率为15.90%(7/44),其中GJB2 235 del C杂合突变3例(6.82%),GJB2 35 del G杂合突变1例(2.27%);SLC26A4 1229C>T纯合突变2例(4.55%),SLC26A4 IVS7-2 A>G杂合突变1例(2.27%)。壮、汉族间耳聋基因突变率比较无统计学意义。结论 GJB2和SLC26A4是广西地区壮族人群非综合征性聋患者最常见的突变基因,GJB2的4个突变位点及SLC26A4的8个突变位点突变率明显低于全国平均水平,其中SLC26A4 IVS11+47T﹥C、1548ins C和GJB2 109 A>G是3个新发现的突变位点。本地区壮汉族之间的耳聋基因突变率无明显的差异性。广西地区壮族人群非综合征性聋患者可能存在罕见的致聋基因或罕见的突变位点,需待进一步研究。     

常见耳聋相关基因在非综合征型聋中的研究进展

耳聋是一种很普遍的感音神经功能紊乱的耳部疾病，是人类最常见的致残原因之一，严重影响人类生活质量。在耳聋患者中遗传性聋约占60%。遗传性聋可分为综合征型聋和非综合征型聋。综合征型聋是指以耳聋合并其他临床症状的遗传综合征，而非综合征型聋是指以单一听力缺失为临床症状的遗传性疾病。本文对非综合征型聋的遗传性基因研究进展做一综述，以期从分子水平探讨耳聋的病因及发病机制。     

DFNA5与遗传性耳聋

遗传性耳聋是危害人类健康的重大疾病之一,根据是否合并其他系统器官疾病,分为综合征性耳聋和非综合征性耳聋,而非综合征性耳聋具有很高的遗传异质性.迄今为止,常染色体显性遗传非综合征性耳聋(DFNA)已成功定位了64个位点,24个基因(Hereditary Hearing Loss Homepage:http://webhost.ua.ac.be/hhh/).第五个常染色体显性遗传非综合征性耳聋基因DFNA 5(OMIM 600994)于1995年在一个高频进展性听力下降的荷兰家系中首先定位在7p15[1],1998年确认了DFNA5的致聋基因[2].本文就已报道DFNA5的基因突变特点、家系的临床特征及目前对该基因功能的研究进展等方面进行综述.     

The Genetic Deafness in Chinese Population

Deafness is an etiologically heterogeneous trait with many known genetic, environmental causes or a combination thereof. The identification of more than 120 independent genes for deafness has provided profound new insights into the pathophysiology of hearing. However, recent findings indicate that a large proportion of both syndromic and nonsyndromic forms of deafness in Chinese population are caused by a small number of mutations.This review is focused on syndromic and nonsyndromic deafness as well as on the latest information linking inherited mitochondrial pathologies to a variety of etiologies of sensorineural deafness in Chinese population. Better understanding of the genetic causes of deafness in Chinese population is important for accurate genetics counseling and early diagnosis for timely intervention and treatment options.     

Connexin mutation testing of children with nonsyndromic, autosomal recessive sensorineural hearing loss

OBJECTIVE: The etiology of hearing loss is heterogeneous and falls into the two broad categories of genetic and environmental. In the genetic subgroup, 70% are non syndromic. Fifty percent of nonsyndromic sensorineural deafness is due to a mutation in the connexin 26 gene. This article presents the detection rate of connexin mutations in a multiethnic Canadian population. METHODS: A study of patients with nonsyndromic hearing loss seen over a period of 2 years who had connexin 26 mutation testing. RESULTS: Nine of the 18 patients had connexin 26 mutations. CONCLUSION: The majority of our patients with connexin 26 mutations had moderate to profound hearing loss. Testing for connexin mutations should be standard care because it accounts for a large proportion of individuals with nonsyndromic hearing loss. Reasons for testing include ruling out a syndromic cause, predicting moderate to profound hearing loss, and the need for language intervention, cochlear implants, and genetic counselling.     

Etiology of syndromic and nonsyndromic sensorineural hearing loss

The past 10 years have seen an explosive gain in our understanding of molecular mechanisms of hearing and deafness. This has already resulted in improved diagnosis for the population with hereditary hearing loss. For syndromic hearing loss, we will see a shift from the historical terminology to a more precise genetic definition based on specific genetic abnormality. Functional studies of nonsyndromic deafness genes will elucidate the complex functional and hemostatic mechanisms in the inner ear. Ultimately, availability of gene therapy for the affected patients will bring to closure the circle of detection, identification, and correction of the disease.     

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.     

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     

与非综合征型聋相关缝隙连接蛋白31及线粒体12SrRNA基因突变

 耳聋是影响人类健康和造成人类残疾的常见疾病,它主要由遗传因素和环境因素引起。遗传性聋包括综合征型聋和非综合征型聋,其中非综合征型聋约占70%。 GJB3及线粒体12SrRNA基因突变和非综合征型聋密切相关。本文就GJB3及线粒体12SrRNA基因突变与非综合征型聋的相关性进行综述,进一步明确其发病的相关性,在明确部分非综合征型聋病因的同时,更好的为患者及其家族成员提供准确的遗传咨询和指导,为临床防聋治聋提供依据及策略。     

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.     

国人无综合征性耳聋患者的线粒体基因组7445^A→G突变263 …

OBJECTIVE: To study the Mitochondrial DNA 7445A-->G mutation in nonsyndromic deafness patients in Chinese population. METHOD: Polymerase chain reaction and restriction fragment length polymorphism (PCR-RFLP) were used to screen the mitochondrial DNA 7445A-->G mutation among 128 nonsyndromic deafness individuals from 32 pedigrees, 135 sporadic nonsyndromic deafness patients and 100 normal subjects. RESULT: The 7445A-->G mutation did not appear in the experiment. CONCLUSION: Incidence of the mitochondrial 7445A-->G mutation was lower than that of mtDNA 1555A-->G mutation in nonsyndromic deafness patients in China.     

耳聋-掌跖皮肤角化综合征的连接蛋白基因型和表型分析

目的GJB2、GJB6、GJB3基因与遗传性耳聋及角化病有关，以GJB2、GJB6、GJB3基因为候选基因，研究1例伴有掌跖角化病的综合征型耳聋先证者的分子病因，探讨其表型及遗传特征。方法 采集先证者及其父母外周血并提取DNA，对GJB2、GJB6、GJB3基因编码区进行PCR扩增，以直接测序的方法进行突变分析。结果 先证者及其父母GJB3、GJB6基因测序未发现突变。先证者携带GJB2基因R75W单等位基因突变，其父母未携带此突变，在证实先证者与其父亲的亲子关系后明确先证者携带的R75W为新生突变。301名中国正常对照中未发现GJB2基因R75W突变。结论 在中国首次发现了GJB2基因新生突变R75W，此突变可能以显性方式遗传，导致耳聋-掌跖皮肤角化综合征。在不同种族R75W导致的耳聋多为双侧重度到极重度感音神经性聋。而皮肤表型的严重程度有所不同。     

Causes of deafness in British Bangladeshi children: a prevalence twice that of the UK population cannot be accounted for by consanguinity alone

Objective: To study the causes and prevalence of sensorineural deafness in Bangladeshi children resident in East London. Methods: This was a cross sectional survey of children of Bangladeshi origin living in East London with bilateral sensorineural hearing loss of 40 db HL or more. In this study, 134 patients were included. The study looked primarily at the causes of sensorineural hearing loss in this population. Results: The prevalence of deafness in Bangladeshi children in East London is approximately 3.86 per 1000 [95% confidence intervals (CI) 3.20, 4.65] which is significantly greater than the average UK prevalence of 1.65 per 1000. The prevalence of deafness in these Bangladeshi children belonging to non‐consanguineous families only, the prevalence falls to 2.73 per 1000 (95% CI 2.19, 3.41). In 60% cases the cause of deafness was genetic. The single most common cause of sensorineural hearing loss in this population was mutations in the GJB2 gene (Connexin 26) in 20 of these patients (17%). Parents were consanguineous in 33% of the families. Conclusion: This study concludes that prevalence of sensorineural deafness in Bangladeshi children is at least 2.3 times the national average. This study also concludes that genetic causes are the common cause of deafness in this ethnic group, with nearly 30% of children with non‐syndromic deafness having mutations in GJB2. Although parental consanguinity was very high in this population it did not account for the whole increase in prevalence.