一个遗传性非综合征型耳聋家系的突变分析

目的分析一个遗传性非综合征型耳聋家系的突变，并探讨缝隙连接蛋白beta2(gap junction protein beta 2，GJB2)基因235delC突变是否会加重线粒体A1555G突变导致的非综合征型耳聋症状。方法对一个母系遗传性非综合征型耳聋核心家系72个成员取外周血提取DNA，经聚合酶链反应扩增后，利用Alw26Ⅰ限制性内切酶酶切及直接测序验证，对其线粒体DNA突变进行研究；利用ApaⅠ限制性内切酶酶切及直接测序验证，筛查核心家系中GJB2基因235delC突变情况，并对GJB2基因235delC和线粒体A1555G突变的关系进行研究。结果在27名母系成员中均发现具有线粒体A1555G突变，呈母系遗传；具有耳聋表型的为21人(77．8％)，家族外显率高；所筛查的包括配偶在内的72名个体中，仅3例具有GJB2基因235delC杂合子突变，且均出现在母系成员中，但3例的耳聋表型却不同。结论线粒体A1555G突变是本家系耳聋遗传易感性的基础，在该家系中GJB2基因的235delC杂合子突变未加重线粒体A1555G突变导致的非综合征型耳聋。     

12个非综合征型遗传性耳聋家系mtDNA12SrRNA，tRNA^Leu（UUR）,tRNA^Ser（UCN）及16SrRNA基因序列分析

目的 探讨mtDNA突变与遗传性耳聋的关系。以及突变家系对氨基糖甙类抗生素（aminoglycoside antibiotic,AmAn)耳毒敏感性差异的原因。方法 调查了12个非综合征型耳聋家系;抽取外周血,提取DNA;PCR扩增线粒体DNA9mitochondrialDNA,mtDNA)目的片段,分别以Alw26Ⅰ、ApaⅠ及XbaⅠ限制性内切酶检测1555^G、3243^G及7445^G点突变,行mtDNA12SrRNA,tRNA^Leu(UUR)、tRNA^Ser(UCN)及16SrRNA基因序列测定。结果 经酶切及测序证实12个家系具有mtDNA突变,形式为：1555^G突变家系10个,7445^G突变家系2个,示发现3243^G突变家系,基因测序显示mtDNA16SrRNA基因6序列变化形式为：2230^G点突变,2230^AG插入,2243^AG插入及2230^AA插入突变,它们在家族性AmAn耳毒敏感性家系中被发现,且呈母系遗传;在AmAn不敏感家系中未被发现,结论 单纯1555^G或7445^G突变家系表现为无诱因的渐进性遗传性耳聋或先天性聋;1555^G或7445^G突变合并16SrRNA基因突变者对AmAn高度敏感,表现为家族性敏感致聋。ⅠⅠ     

综合征型遗传性耳聋的研究现状

本综述了综合征性遗传性耳聋的发病率，基因定位与克隆的研究现状总结了６０余种综合征性遗传性耳聋的临床表型。     

非综合征型遗传性耳聋基因研究的进展及前景

本就非综合征性遗传性耳聋基因研究的进展及其前景进行了综述，中分析了非综合性征遗传性耳聋基因定位与克隆的研究现状，以及基因突变与临床表现型的关系，展望了耳聋基因研究的重要意义和应用前景。     

遗传性耳聋家系的致病原因分析及产前诊断

目的 对3个先天性耳聋家系进行遗传性耳聋基因检测及突变类型分析,为再生育的家庭提供遗传咨询及产前诊断。方法 对在宁波市妇女儿童医院就诊的3例先天性耳聋患儿抽取静脉血,提取DNA。先应用目标基因捕获和高通量测序技术对先证者进行耳聋基因相关的全外显子和相邻内含子测序,利用生物信息学技术对测序数据进行分析,筛选相关变异基因并对其进行致病性分析。再应用Sanger测序法对先证者及其父母做基因突变位点验证。最后对第二胎需要进行产前诊断的孕妇采集羊水进行位点验证。结果 家系1先证者中检出肌球蛋白XVA(myosinXVA,MYO15A)基因c.2075C>A、c.4520G>A、c.6668C>T和c.10250＿10252del杂合突变。家系2先证者中检出MYO15A基因c.5964+3G>A和c.7395+6T>G复合杂合突变。家系3先证者中检出缝隙连接蛋白β2(gap junction protein beta 2,GJB2)基因c.299＿300delAT和c.109G>A复合杂合突变。产前诊断结果显示家系1和家系2胎儿的基因型均与先证者的不同,听力表型...     

运城地区耳聋患者常见耳聋基因突变分析

目的通过筛查运城地区耳聋患者常见耳聋基因GJB2、PDS和线粒体DNAl555位点的突变频率,来研究该地区常见耳聋基因突变的发生情况。方法采集运城市特殊教育学校75例耳聋患者外周血,对目的基因扩增并测序。结果75例患者中,45例患者的GJB2基因发生突变,其中,c．235delc、e．79G〉A和c.341A〉G的突变频率较高,分别为12％、22％和18．7％,另外还检测出4个突变频率较低的位点C．608T〉C（2％）、C．109G〉A（0．67％）、c．368C〉A（1．33％）和C．176—191del16（0．67％）;3例患者的PDS基因第19外显子发生突变,C．2168A〉G与IVs7—2G〉A突变频率分别为1．33％和2％;仅有1例患者mtDNA1555发生突变。结论通过对山西运城地区常见耳聋基因突变的研究,对建立山西省耳聋基因突变数据库提供素材,同时也为耳聋的预防,基因诊断及治疗提供强有力的依据。     

遗传性非综合征型耳聋的临床实践指南

遗传因素是非综合征型聋常见的致病原因。随着分子检测技术的发展和日臻成熟,基因诊断和遗传咨询越来越多地影响着耳聋的临床实践。新生儿听力筛查的普及有助于耳聋的早期发现,耳聋基因筛査和诊断的普及有助于明确其病因,临床基因诊断和遗传咨询则有助于耳聋的早期干预。至今发现的非综合征型聋的致病基因有110个,鉴定其致病基因在临床上仍存在很多挑战。临床遗传咨询和产前诊断的开展,对耳聋基因检测和数据解读提出了更高的要求。本指南阐述了非综合征型耳聋的人群发病率、致病基因谱、遗传方式、疾病发展过程、临床表现、基因型-表型对应关系、基因诊断、治疗和干预,以及耳聋预防和再发风险评估等关键问题,为遗传咨询师、临床耳科医师及基因检测专业人员提供指导。     

非综合征型遗传性耳聋基因及分子诊断研究进展

耳聋是严重影响人类生存质量的致残性疾病,先天性耳聋多由遗传因素导致。遗传性耳聋包括综合征型耳聋和非综合征型耳聋,其中非综合征型耳聋约占70%,分子诊断技术是目前检测遗传性耳聋的主要方法。本文对我国非综合征型遗传性耳聋致病基因及耳聋的分子诊断技术进行简述。     

线粒体DNA A1555G和961 insC双重突变导致的非综合征型遗传性耳聋

目的探讨一个非综合征型遗传性耳聋大家系线粒体DNA(mitoehondrial DNA，mtDNA)突变类型。方法临床听力测试已明确诊断，并收集非综合征型遗传性耳聋分支家系中33人及6例散发聋患者的外周静脉血样本，从白细胞中提取DNA，聚合酶链反应扩增mtDNA目的片段，分别用BsmA I、Apa I及Xba I限制性内切酶检测1555G、3243G和7445G点突变，对相关的扩增片段进行基因测序。结果酶切检测，家系中17例耳聋患者均为1555G点突变阳性，非母系成员及散发聋病例均为阴性。测序结果：6例酶切显示1555G突变阳性病例均发现(nt)1555A→G转换和(nt)961C插入，3243G、7445G点突变阴性。结论在该非综合征型遗传性耳聋大家系中，mtDNA 12SrRNA基因区域A1555G和961insC的双重突变可能共同参与了听力损害的过程。     

阳泉地区非综合征性耳聋患者常见耳聋基因突变的分析

目的通过对阳泉市盲聋哑学校69例耳聋患者进行GJB2、PDS及线粒体DNA基因热点突变筛查,分析该地区耳聋的突变分布及分子病因。方法收集山西省阳泉市69例耳聋患者,对所有患者线粒体DNAA1555G／C1494T、GJB2基因、PDS基因第7、8和19外显子进行扩增及测序。结果69例非综合征性耳聋患者共有60例检测到基因突变,突变率为86．96％（60／69）。57例患者检出GJB2基因突变,检出率达82．61％（57／69）,其中C．235delC突变率为10．14％;3例患者有PDS基因突变,分别为c．2168A〉G l例,IVS7-2G〉A 2例;未检测到线粒体DNAA1555G／C1494T突变。结论山西省阳泉市常见耳聋基因突变以GJB2基因突变率较高,为耳聋的诊断与治疗提供依据。     

Comprehensive molecular analysis of 61 Egyptian families with hereditary nonsyndromic hearing loss

Nonsyndromic hearing loss is an extremely heterogeneous disorder. Thus, clinical diagnostics is challenging, in particular due to differences in the etiology of hearing loss between populations. With this study, we wanted to elucidate the genetic basis of hearing loss in 61 consanguineous Egyptian families. In 25 families, linkage analysis was used as a prescreening to identify regions for targeted sequencing of candidate genes. Initially, the coding regions of 12 and later of 94 genes associated with hearing loss were enriched and subjected to massively parallel sequencing (MPS) with diagnostic yields of 36% and 75%, respectively. Causative variants were identified in 48 families (79%). They were found in 23 different genes with the majority being located in MYO15A (15.3%), SLC26A4 (9.7%), GJB2 (8.3%), and MYO7A (6.4%). As many as 32 variants were novel ones at the time of detection. Five variants were shared by two, three, or even four families. Our study provides a first survey of the mutational spectrum of deaf patients in Egypt revealing less GJB2 variants than in many European populations. It underlines the value of targeted enrichment of well-selected deafness genes in combination with MPS in the diagnostics of this frequent and genetically heterogeneous disorder.     

非综合征性聋分子病因学分析——TMIE基因突变筛查报告

目的探讨TMIE基因突变与中国人群非综合征性聋的关系以及TMIE基因突变频率和特性。方法收集中国人群中散发非综合征性聋患者123例、遗传性非综合征性聋家系先证者62例及部分成员、以及健康对照60例临床资料及外周血DNA,应用聚合酶链反应（polymerase chain reaction,PCR）扩增TMIE基因编码区片段,通过变性高效液相色谱法（denaturing high—performance liquid chromatography,DHPLC）筛查TMIE基因突变,经DNA测序检测突变。结果在两个散发非综合征性聋患者和一个常染色体显性遗传性非综合征性聋家系中先证者TMIE基因编码区PCR产物DHPLC结果异常,但序列检测没有发现TMIE基因编码区的突变,仅分别发现第二内含子区域IVS2—53G〉A和第三外显子506A—G基因单核苷酸多态性呈杂合状态。其中506A—G单核苷酸多态未见有报道。结论中国人群中遗传性非综合征性聋患者TMIE基因突变频率较低,不可能是中国人群中非综合征性聋的主要致病基因。     

七个非综合征型耳聋家系患者的mtDNA A1555G突变性质与特点

目的 探讨非综合征型耳聋家系患者mtDNA A1555G突变性质及其特点,探索临床表型多样性的分子遗传学基础.方法 应用聚合酶链反应-限制性片段长度多态和实时荧光-扩增阻碍突变系统-定量PCR(real time-amplification refractory mutation system-quantitative PCR,RT-ARMS-qPCR)检测7个非综合征型耳聋家系71个成员的mtDNA A1555G突变,并收集、分析其临床资料.结果 7个家系中所有受检的母系成员mtDNA A1555G突变均为阳性,突变性质含同质性和异质性两种;非母系成员及配偶该突变为阴性.7个家系mtDNA A1555G同质性突变的拷贝数与耳聋轻重程度相关(R=0.341,P=0.022);mtDNA A1555G异质性突变的拷贝数与耳聋轻重程度相关(R=0.85,P=0.015).结论 mtDNA A1555G突变可导致非综合征型耳聋和氨基糖甙类抗生素致聋,其突变性质含同质性和异质性两种,且含mtDNA A1555G位点的突变型与野生型的比例与耳聋的严重程度密切相关.     

New role of LRP5, associated with nonsyndromic autosomal‐recessive hereditary hearing loss

Human hearing loss is a common neurosensory disorder about which many basic research and clinically relevant questions are unresolved. At least 50% of hearing loss are due to a genetic etiology. Although hundreds of genes have been reported, there are still hundreds of related deafness genes to be found. Clinical, genetic, and functional investigations were performed to identify the causative mutation in a distinctive Chinese family with postlingual nonsyndromic sensorineural hearing loss. Whole‐exome sequencing (WES) identified lipoprotein receptor‐related protein 5 (LRP5), a member of the low‐density lipoprotein receptor family, as the causative gene in this family. In the zebrafish model, lrp5 downregulation using morpholinos led to significant abnormalities in zebrafish inner ear and lateral line neuromasts and contributed, to some extent, to disabilities in hearing and balance. Rescue experiments showed that LRP5 mutation is associated with hearing loss. Knocking down lrp5 in zebrafish results in reduced expression of several genes linked to Wnt signaling pathway and decreased cell proliferation when compared with those in wild‐type zebrafish. In conclusion, the LRP5 mutation influences cell proliferation through the Wnt signaling pathway, thereby reducing the number of supporting cells and hair cells and leading to nonsyndromic hearing loss in this Chinese family.     

Molecular analysis of mitochondrial gene mutations in Korean patients with nonsyndromic hearing loss

Mutations in mitochondrial DNA (mtDNA) are a major cause of hearing loss. In this study, we performed a systematic mutational screening of the 12S rRNA, tRNA Ser(UCN), tRNA Lys and tRNA Leu(UUR) genes in 227 unrelated patients with nonsyndromic hearing impairment for the first time in a Korean population. We found two individuals with an A1555G mutation, which is a frequency (0.9%) lower than that of other East Asians. Furthermore, two novel variants (C895T and 961-CC insertion) in the 12S rRNA gene were identified in the affected individuals, but were absent in 217 controls, indicating that they may play a role in the pathogenesis of hearing loss. Notably, 961delT and T1005C mutations were identified at similar frequencies in both patients and control subjects. Our data suggest that these variants seem to be polymorphisms rather than causes of disease. On the other hand, we did not find any of the known deafness-associated mutations in these tRNA genes. These data suggest that the 12S rRNA gene may be a hot spot for mitochondrial mutations causing hearing loss in the Korean population.     

遗传性非综合征型耳聋患者GJB2基因编码序列分析

目的 对6个遗传性非综合征型耳聋家系成员的GJB2基因编码序列进行分析,寻找耳聋患者的致病基因突变,探讨GJB2基因突变致病的遗传模式.方法 提取患者及家系成员的外周血基因组DNA,扩增GJB2基因的编码序列,然后对扩增产物进行DNA测序,对出现重叠峰形的扩增产物进行TA克隆后再测序,确定基因突变是否存在于同一拷贝.结果 6个遗传性非综合征型耳聋家系中,4个家系是GJB2基因突变所致.患者的GJB2基因突变包括235delC、299-300delAT、79G→A+341A→G和109G→A.非致聋突变79G→A与341A→G组合具有致聋效应,109G→A和235delC的杂合突变可能也有致聋效应.结论 GJB2基因突变致聋具有明显异质性,非致聋突变并非完全不致聋,环境因素或其它基因可能参与GJB2基因突变所致耳聋.     

非综合征型遗传性耳聋两家系线粒体基因突变分析

目的 探讨母系遗传非综合征型耳聋发病机理及7445^G点突变在这类家系及散发感音神经性耳聋病例中的发生率，为建立相应的基因诊断方法提供依据。方法 收集两个母系遗传非综合征型耳聋家系和14个感音神经性耳聋散发病例；抽外周血标本，从白细胞中提取DNA；聚合酶链反应扩增线粒体DNA（mitochondrial DNA,mtDNA）目的片段，分别以Alw 26Ⅰ、ApaⅠ及XbaⅠ限制性内切酶检测1555^G、3243^G及7445^G点突变；行mtDNA 12S r RNA、tRNA^Leu(UUR)、tRNA^Ser(UCN)基因测序。结果 经酶切检测，两家系中12例为7445^G点突变阳性，其余6例及14例散发病例均为阴性，所有病例1555^G、3243^G点突变均阴性；7445^G点突变呈母系遗传。mtDNA测序显示，所有病例1555^G、3243^G点突变均阴性；酶切显示为7445^G突变阳性病例经基因测序均发现有（nt)7445A→G替换。结论 7445^G点突变在母系遗传非综合征型耳聋家系中有较高的发生率，而在散发病例中发生率很低；7445^G结合1555^G点7突变筛查对这类耳聋的诊断有重要意义。     

Mutations of the RDX gene cause nonsyndromic hearing loss at the DFNB24 locus

Ezrin, radixin, and moesin are paralogous proteins that make up the ERM family and function as cross-linkers between integral membrane proteins and actin filaments of the cytoskeleton. In the mouse, a null allele of Rdx encoding radixin is associated with hearing loss as a result of the degeneration of inner ear hair cells as well as with hyperbilirubinemia due to hepatocyte dysfunction. Two mutant alleles of RDX [c.1732G>A (p.D578N) and c.1404_1405insG (p.A469fsX487)] segregating in two consanguineous Pakistani families are associated with neurosensory hearing loss. Both of these mutant alleles are predicted to affect the actin-binding motif of radixin. Sequence analysis of RDX in the DNA samples from the original DFNB24 family revealed a c.463C>T transition substitution that is predicted to truncate the protein in the FERM domain (F for 4.1, E for ezrin, R for radixin, and M for moesin) (p.Q155X). We also report a more complete gene and protein structure of RDX, including four additional exons and five new isoforms of RDX that are expressed in human retina and inner ear. Further, high-resolution confocal microscopy in mouse inner ear demonstrates that radixin is expressed along the length of stereocilia of hair cells from both the organ of Corti and the vestibular system.