常染色体显性遗传性听神经病家系候选致病基因突变筛查

目的:了解DIAPH3基因以及25个已克隆的常染色体显性遗传非综合征型聋(DFNA)基因的已知突变是否与一个中国听神经病家系的发病有关。方法:以一个现存3代9人的常染色体显性遗传性听神经病核心家系为研究对象,对所有家系成员进行DIAPH3基因5′端非翻译区(5′UTR)的PCR扩增,1例听神经病患者进行DIAPH3、GJB2和GJB3基因全部编码区以及对其余23个DFNA基因的50个外显子进行PCR扩增,扩增产物经纯化后直接测序,筛查致病突变。结果:该家系未发现DIAPH3基因5′UTR的已知突变c.-172G>A和新的致聋突变,对GJB2、GJB3基因全部编码区及其余23个DFNA基因已知突变位点的筛查也无阳性发现。结论:结合前期工作,对照该家系成员DIAPH3基因及已克隆的25个DFNA基因的筛查结果,进一步提示该家系听神经病的发生可能是由新基因所致。     

非综合征性耳聋患者连接蛋白26基因突变的研究

目的　探讨中国人非综合征性耳聋患者连接蛋白 2 6 (connexin 2 6 ,Cx2 6 )基因突变频率和特性。方法　收集中国散发先天性聋哑儿童 16例 ,常染色体隐性遗传性聋 39例 (39个家系 ) ,10岁前开始听力下降的常染色体显性遗传性聋 30例 (30个家系 )和健康对照组 10 0例。聚合酶链反应 单链构象多态 (singlestrandconformationalpolymorphismanalysisofpolymerasechainreaction ,PCR SSCP)分析初筛可疑突变者 ,SSCP分析发现异常构象带后再行DNA测序。结果　健康对照组中 15例发现 5种多态性改变 ,耳聋患者中 10例发现 6种多态性改变。散发先天性聋哑和常染色体隐性遗传非综合征性耳聋中未发现致病突变。 1个常染色体显性遗传性聋家系发现所有患者 (3例 )Cx2 6基因的编码区2 99 30 0位碱基AT杂合性缺失 ,导致移码突变 ,翻译的蛋白质截短 ,该家系听力正常者无此突变。结论　蒙古人种中常染色体隐性遗传性非综合征性耳聋的Cx2 6基因突变率可能低于其他人种。Cx2 6基因编码区 2 99 30 0位碱基AT杂合性缺失可致常染色体显性遗传性聋DFNA3型     

特大常染色体显性遗传聋家系听力学特征及候选致病基因突变筛查

目的探讨一中国常染色体显性遗传聋大家系的听力学特征,进行已知致聋基因已知突变位点的筛查。方法经知情同意,对家系成员进行全身检查及听力学检测,获得血样标本;整理分析家系资料并绘制系谱图;用基因组DNA抽提试剂盒提取外周血DNA。对2例家系患者DNA进行GJB2和GJB3基因全部编码区突变检测,对其余23个已知常染色体显性遗传性耳聋(DFNA)基因的74个已知突变位点所涉及的50个外显子进行PCR扩增和直接测序分析。结果该家系共7代199人,现存4代176人,耳聋患者54人。系谱分析显示,耳聋表型代代相传,男女患病人数分别为24和30,符合常染色体显性遗传特征。听力学表现为:迟发性、进行性、双侧对称性、感音神经性听力损失,首先是高频区受损,并快速向中、低频扩展。GJB2、GJB3基因全部编码区及其余23个DFNA基因已知突变位点的序列分析均无阳性发现。结论该家系是一个非综合征型常染色体显性遗传聋大家系,耳聋表型为迟发性、进行性、双耳对称性感音神经性听力损失;初步分子遗传学分析提示可能由新基因或已知基因的新突变致病。     

中国Y连锁遗传性聋DFNY1家系POU3F4基因突变的检测

目的:进行Y连锁遗传性聋(Y-linked hereditary hearing impairment)家系的候选基因——POU3F4基因的突变分析。方法: 在POU3F4基因的全部编码序列设计5对引物进行聚合酶链反应 (polymerase chain reaction,PCR)扩增反应。应用PCR-单链构像多态性(single-strand conformation polymorphism SSCP)方法对DFNY1 家系中的43名成员进行突变检测及鉴定。结果:POU3F4基因的5 对引物均有较好的扩增效果,PCR-SSCP的多态性分析显示所有家系成员在POU3F4基因中均未检测到多态及突变。结论:本研究通过对一个位于X染色体与Y染色体存在同源交换区域的耳聋基因POU3F4 基因的检测排除了该基因易位到Y染色体导致DFNY1家系耳聋的可能性,说明中国Y连锁遗传性聋家系的致病基因更多可能是位于Y染色体上的基因突变所致。图2表1参10     

中国常染色体显性遗传非综合征型耳聋人群缝隙连接蛋白31基因突变分析

目的研究缝隙连接蛋白31编码基因(GJB3)突变在中国常染色体显性遗传非综合征型耳聋(autosomal dominant non-syndromic hearing loss,DFNA)人群中的特征,了解中国DFNA家系GJB3基因突变发生率及突变谱。方法应用聚合酶链反应产物直接测序方法对31个中国DFNA家系先症者进行GJB3基因编码区突变检测及鉴定。结果在31例先症者中发现已报道的GJB3基因的两种单核苷酸改变,其中,4例存在357C>T杂合碱基改变,1例存在357C>T纯合碱基改变;357C>T碱基改变没有引起氨基酸变化;1例受检者存在250G>A杂合碱基改变,250G>A引起GJB3 84位编码氨基酸缬氨酸变成异亮氨酸(V841)。结论在中国DFNA人群中,没有发现GJB3基因新的突变形式,初步结果提示,GJB3基因突变在中国DFNA耳聋群体中不常见。     

中国Y连锁遗传性聋DFNY1家系POU3F4基因突变的检测

目的进行Y连锁遗传性聋(Y—linked hereditary heating impairment)家系的候选基因——POU3F4基因的突变分析。方法在POU3F4基因的全部编码序列设计5对引物进行聚合酶链反应(polymerase chain reaction，PCR)扩增反应。应用PCR-单链构像多态性(single-strand conformation polymorphism SSCP)方法对DFNY1家系中的43名成员进行突变检测及鉴定。结果POU3F4基因的5对引物均有较好的扩增效果，PCR—SSCF，的多态性分析显示所有家系成员在POU3F4基因中均未检测到多态及突变。结论本研究通过对一个位于X染色体与Y染色体存在同源交换区域的耳聋基因POU3F4基因的检测排除了该基因易位到Y染色体导致DFNY1家系耳聋的可能性，说明中国Y连锁遗传性聋家系的致病基因更多可能是位于Y染色体上的基因突变所致。     

POU3F4基因与X连锁的遗传性聋

POU3F4基因是X染色体上唯一已克隆的非综合征型耳聋相关基因,该基因突变导致的遗传性聋具有显著的遗传学特点和特异的颞骨影像学改变.本文对POU3F4基因及其突变引起的耳聋做简要综述.     

一个POU4F3基因变异所致常染色体显性聋15型家系的遗传学分析

目的 对一个常染色体显性非综合征型进行性听力减退的患者家系进行基因分析，以明确其可能的遗传学病因。方法 应用全外显子组测序方法对先证者进行基因分析，应用Sanger测序法对可疑致病位点进行验证并在家系成员中进行检测。结果 该家系共4代，现有患者6人，均表现为重度-极重度感音神经性听力下降，先证者男，36岁，6岁时发病，检测到非综合征型常染色体显性聋15型(DFNA15)相关基因POU4F3 c.337C>T (p.Q113*)杂合变异，该家系中其它5例患者(Ⅱ-2、Ⅲ-2、Ⅲ-4、Ⅲ-5和Ⅲ-7)均检测到该杂合变异，而4例听力正常成员(Ⅲ-1、Ⅲ-3、Ⅲ-6、Ⅳ-2)未检测到该变异。根据美国医学遗传学和基因组学学会(ACMG)相关指南对该变异进行致病性评级，变异证据为PVS1+PM2+PP1,属致病变异。结论 该家系为一种罕见的由POU4F3基因杂合变异引起的DFNA15型耳聋家系，且可能存在遗传早现现象，POU4F3基因c.337C>T (p.Q113*)变异是该家系耳聋的遗传学病因，可对该家系的遗传咨询提供依据。     

遗传性耳聋资源收集保存及基因定位克隆

目的建立聋病遗传资源收集网络,着重收集具有中国特色的聋病遗传资源,进行聋病基因定位克隆及相关的分子流行病学研究。方法通过遗传资源收集网络进行聋病遗传资源的收集,建立资源库进行遗传资源的表型鉴定和分析。应用微卫星标记的连锁分析及候选基因法进行家系的基因定位克隆和分子流行病学研究。结果共收集到含有多种耳聋表型的大小家系2071个,其中涵盖了单基因病孟德尔遗传的全部遗传方式:包括X-连锁遗传家系2个,Y-连锁遗传家系1个(命名为DFNY1基因座)、常染色体显性遗传性耳聋大家系12个(完成了基因定位5个)、常染色体隐性遗传性耳聋核心家系619个以及线粒体突变母系遗传性耳聋家系76个;大前庭水管综合征163例;听神经病108例;不明原因感音神经性耳聋478例;西北地区聋哑学校聋哑患者612例。对1489例散发患者进行了线粒体基因12S rRNA 1555G,缝隙连接蛋白基因(GJB2,GJB3和GJB6)以及SLC26A4基因的突变筛查与分析。其中西北地区612例聋哑人群中发现27．92％患者分别存在三个基因的突变,mtDNAA1555G平均阳性率为9．15％,GJB2为9．97％,SLC26A4为8．8％。结论遗传性听力损失是非常常见的耳聋疾病,其发病率超出原有的预测。基于大家系的基因定位研究有望发现新的基因座位及新的基因突变。分子流行病学研究发现遗传因素在先天性聋和学语后听力损失中的作用强于环境因素,并发现中国人群具有耳聋基因的高发病率和特异的突变图谱。     

进行性非综合征型聋家系临床表型及遗传学分析

目的分析一个连续五代常染色体显性遗传性非综合征型聋家系的临床表型及遗传学特征。方法对该耳聋家系成员进行病史采集、全身及听力学检查,绘制遗传图谱并进行遗传学特征分析。应用微卫星标记连锁分析方法及外显子序列分析对常染色体显性遗传(DFNA)23个基因的22个位点进行初步筛查。结果该耳聋家系共五代,现存家系成员44人,参与本研究的39人中耳聋患者16人,除1人为语前聋外,其他患者均表现为迟发性、渐进性听力下降,发病年龄介于14～40岁,早期以中频听力下降为主,逐渐累及高频,随着年龄的增长,呈全频听力下降。除DFNA5外,各DFNA位点连锁分析所得LOD值均<-2,提示该家系的致聋基因与这些位点均不连锁。对家系中2例患者和2例正常者DFNA5的所有外显子进行测序分析,未发现突变。结论该家系遗传方式符合常染色体显性遗传规律,表现为以中高频听力下降为主的感音神经性聋;对已知耳聋基因位点进行筛查,未发现明确的阳性位点;通过新一代测序技术进行全外显子组分析可能发现新的感音神经性聋致病基因。     

The DFNA2 locus for hearing impairment: two genes regulating K+ ion recycling in the inner ear

DFNA2 is a locus for autosomal dominant non-syndromal hearing impairment (ADNSHI) located on chromosome 1p34 and six linked families have been identified. An audiometric study of these families showed that despite small differences in the phenotype all families suffer from progressive hearing impairment starting in the high frequencies. A detailed genetic analysis revealed that this deafness locus contains more than one gene responsible for hearing impairment. Thus far, two genes on chromosome 1p34 have been implicated in ADNSHI. The first, connexin 31 (GJB3), is a member of the connexin gene family. Connexins form gap junctions. These are connections between neighbouring cells that allow transport of small molecules. GJB3 mutations were found in two small Chinese families with ADNSHI. The second is KCNQ4, a voltage-gated K+ channel. Mutations in KCNQ4 were first found in a small French family, later in five of the six linked DFNA2 families. No GJB3 or KCNQ4 mutations were detected in patients of an extended Indonesian DFNA2 family. Two pathways have been proposed for the recycling of K+ from the hair cells back to the endolymph. These pathways involve the use of gap junctions, K+ pumps and K+ channels. The expression of GJB3 and KCNQ4 in the inner ear and their functions suggest that both DFNA2 genes may play a role in K+ homeostasis.     

The genetic load for hereditary hearing impairment in Chinese population and its clinical implication

Objective To understand the genetic load in the Chinese population for improvement in diagnosis, prevention and rehabilitation of deafness. Methods DNA samples, immortalized cell lines as well as detailed clinical and audiometric data were collected through a national genetic resources collecting network. Two conventional genetic approaches were used in the studies. Linkage analysis in X chromosome and autosomes with microsatellite markers were performed in large families for gene mapping and positional cloning of novel genes. Candidate gene approach was used for screening the mtDNA 12SrRNA, GJB2 and SLC26A4 mutations in population-based samples. Results A total of 2,572 Chinese hearing loss families or sporadic cases were characterized in the reported studies, including seven X-linked, one Y-linked, 28 large and multiplex autosomal dominant heating loss families, 607 simplex autosomal recessive hereditary hearing loss families, 100 mitochondrial inheritance families, 147 GJB2 induced heating loss cases, 230 cases with enlarged vestibular aqueduct(EVA) syndrome, 169 sporadic cases with auditory neuropathy, and 1,283 sporadic sensorineural hearing loss cases. Through linkage analysis or sequence analysis, two X-linked families were found transmitting two novel mutations in the POU3F4 gene, while another X-linked family was mapped onto a novel locus, nominated as A UNX1 (auditory neuropathy, X-linked locus 1). The only Y-linked family was mapped onto the DFNY1 locus(Y-linked locus 1, DFNY1). Eight of the 28 autosomal dominant families were linked to various autosomal loci. In population genetics studies, 2,567 familial cases and sporadic patients were subjected to mutation screening for three common hearing loss genes: mtDNA 12S rRNA 1555G, GJB2 and SLC26A4. The auditory neuropathy cases in our samples were screened for OTOF gene mutations. Conclusions These data show that the Chinese population has a genetic load on hereditary heating loss. Establishing personalized surveillance and prevention models for hearing loss based on genetic research will provide the opportunity to decrease the prevalence of deafness in the Chinese population.     

非综合征型遗传性聋家系DFNA11型基因座位的定位研究

目的利用中国遗传性聋家系（2029家系）进行基因定位研究，为进一步克隆耳聋致病基因奠定基础。方法通过解放军总医院耳鼻咽喉研究所遗传性聋资源收集网络采集到一个六代遗传性聋大家系（173人），应用全基因组的微卫星DNA标记进行基因扫描和基因分型，并利用Linkage等连锁分析软件对基因分型结果进行分析。结果运用全基因组扫描连锁分析，将2029家系的耳聋致病基因定位在11号染色体长臂上。有意义地肯定的连锁标记位于D11S165-D11S1874区域，两点连锁分析的最大似然比（log odds score，LOD）值为5．71（θ=0．05），定位区间为25．34cM（centimorgan）。结论一个中国非综合征型遗传性聋家系的致病基因座位为进一步克隆新的耳聋基因及探索Myosin7A基因对中国耳聋家系的贡献提供了模板。     

Audiometric characteristics of a Dutch family linked to DFNA15 with a novel mutation (p.L289F) in POU4F3

OBJECTIVE: To report on the audiometric characteristics of a large Dutch family linked to DFNA15 with a novel mutation (p.L289F) in POU4F3 (OMIM 602460). DESIGN: Clinical investigation. SETTING: Tertiary referral center. PATIENTS: Family members from a large 5-generation pedigree with sensorineural hearing impairment segregating as an autosomal dominant trait. MAIN OUTCOME MEASURES: Cross-sectional and longitudinal analyses of pure-tone audiometric data, and cross-sectional analyses of speech audiometry data. RESULTS: Overall, a flat to gently downsloping audiometric configuration was observed with a progression rate of approximately 0.8 dB/y across most frequencies. Speech recognition scores remained fairly good in relation to age and hearing level compared with a group of patients with presbycusis. Interindividual variability was observed in terms of subjective onset age and audiometric configuration. Two mutation carriers, who reported vestibular symptoms, underwent vestibular examination and showed hypofunction of the vestibular labyrinth. CONCLUSIONS: The audiometric phenotype of the Dutch family linked to DFNA15 with a novel mutation in POU4F3 is comparable to that observed in the original Israeli family linked to DFNA15. Relatively good speech recognition scores suggest outer hair cell involvement. DFNA15 may represent a cochleovestibular disorder.     

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。     

screening of gjb2 mutations in chinese population

The GJB2 gene(connexin 26) has been shown to be responsible for DFNB1 and DFNA3. We screened the GJB2 gene in 488 patients with prelingual deafness(Group 1), 124 with postlingual deafness(Group 2), and 117 normal hearing subjects(Group 3). We found that, in Group 1, 65 patients(13.32%) were homozygotes or compound heterozygotes and 51 patients (10.45%) carried a single pathogenic mutation. The 235delC mutation was the most frequent mutation, accounting for 73.22% of the known pathogenic alleles in Group 1. No homozygotes or compound heterozygotes were detected in Group 2 or Group 3. Some postlingual deaf patients (2.42%) and normal hearing subjects(4.27%) were 235delC carriers. Our preliminary data indicate that 235delC, the most frequent mutation identified in this study, is a major cause for prelingual deafness.