KCNQ4基因的多态性与高频听力下降的研究

目的对中国散发高频听力下降患者中KCNQ4基因突变情况进行筛查，研究该基因第二内含子多态性与高频感音神经性聋的关系。方法在聋病门诊收集散发高频感音神经性聋患者71例，另外选取健听对照40例。采取PCR扩增，直接测序的方法检测KCNQ4基因第二内含子多态性。结果实验组的71名患者中。有16名患者出现47bp的插入或缺失，其中有5名患者出现第二内含子47bp的缺失；11名患者出现第二内含子47bp的插入。对照组的40名成员中，有2名成员出现47bp的插入。这2名成员均为男性，听力为正常，且没有耳聋的家族史。听力正常的成员中没有发现47bp的缺失。结论这个改变对听力的影响可能是通过外显子2与3的剪切拼接形式的变异而影响钾通道蛋白质的功能的。这仍需要进一步研究。     

Wolfram综合征Ⅰ型基因异质性突变引起低频非综合征型聋

目的分析常染色体显性遗传的低频非综合征感音神经性聋与Wolfram综合征Ⅰ型（wolfram syndrome 1，WFSl）基因WFS1的关系以及WFS1基因突变特性，从分子遗传学水平探讨其致病机理。方法收集6个低频非综合征感音神经性聋家系中28例成员以及140例健康对照个体的外周血DNA样本；采用聚合酶链反应，直接序列分析和限制性片断长度多态性分析方法，进行WFS1基因编码区的筛查。结果发现2个家系6例耳聋成员测序结果异常。1个家系发现所有耳聋患者WFS1基因的编码区2379位碱基G杂合性改变成A，导致错义突变；另1家系先证者WFS1基因的编码区2016位碱基G杂合性改变成T，先证者之妹2776位碱基G杂合性改变成A，导致错义突变；先证者之母为一Wolfram综合征伴有心理障碍患者，发现其为2016位2776位碱基复合型错义突变。这2个家系听力正常者及健康对照者中无此突变。结论WFS1基因异质性突变引起低频非综合征感音神经性聋，主要突变为错义突变，遗传咨询和基因检测对该类型耳聋诊治具有指导意义。     

Wolfram 综合征I型基因异质性突变引起低频非综合征型聋

目的分析常染色体显性遗传的低频非综合征感音神经性聋与Wolfram 综合征Ⅰ型(wolfram syndrome 1, WFS1)基因WFS1的关系以及WFS1基因突变特性,从分子遗传学水平探讨其致病机理.方法收集 6个低频非综合征感音神经性聋家系中28例成员以及140例健康对照个体的外周血DNA样本;采用聚合酶链反应,直接序列分析和限制性片断长度多态性分析方法,进行WFS1基因编码区的筛查.结果发现2个家系6例耳聋成员测序结果异常.1个家系发现所有耳聋患者WFS1基因的编码区2379位碱基G杂合性改变成A,导致错义突变;另1家系先证者WFS1基因的编码区2016位碱基G杂合性改变成T,先证者之妹2776位碱基G杂合性改变成A,导致错义突变;先证者之母为一Wolfram综合征伴有心理障碍患者,发现其为2016位2776位碱基复合型错义突变.这2个家系听力正常者及健康对照者中无此突变.结论 WFS1基因异质性突变引起低频非综合征感音神经性聋,主要突变为错义突变,遗传咨询和基因检测对该类型耳聋诊治具有指导意义.     

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.     

感音神经性聋高频听力易损机制

感音神经性聋是临床常见的疾病,包括噪声性聋、老年性聋、药物性聋、突发性聋等。感音神经性聋多以高频听力损失为主要表现,或由高频听力下降开始（Cole,1988;Mur-phy,1991）。以往人们对高频听力损失的认识比较局限,为何感音神经性聋高频听力比低频更容易受损,并没有明确的结论,本文就感音神经性聋高频听力损失的原因和机理做一综述,以期为采取合适的预防和治疗方案提供依据。     

一个新定位的非综合征型低频感音神经性听力下降家系WHRN基因突变分析

目的 对一个新定位的非综合征型低频感音神经性听力下降家系位点区域内的WHRN基因进行突变检测,分析WHRN基因突变与该家系表型的关系.方法 针对WHRN基因的全部编码序列设计11对引物,进行WHRN基因的PCR扩增,对PCR产物进行双向直接测序,检测WHRN基因突变.结果 在WHRN基因的12个外显子中,检测到位于第6和第10个外显子上的3种序列改变方式,均为杂合性突变,这3种突变未与耳聋表型相分离.结论 这个新定位的非综合征型低频感音神经性听力下降家系耳聋表型不是由WHRN基因编码区的突变所致.     

分泌性中耳炎与感音神经性聋

分泌性中耳炎引起的听力下降主要为传导性聋，但部分患者可合并感音神经性聋，尤其在高频段出现骨导听力下降。本文对此现象的机制及国内外的研究现状和主要观点进行综述。     

Baraitser-Winter综合征患者感音神经性聋发生机制的研究进展

Baraitser-Winter综合征（Baraitser-Winter syndrome,BWS）是一种罕见的常染色体显性遗传发育障碍疾病,可伴有进行性感音神经性聋。有研究显示1%的人类基因表达与听觉功能有关。目前为止,已发现超过1000个基因突变可导致遗传性听力损失。伴有感音神经性聋的BWS主要是由胞质表达的肌动蛋白基因ACTB或ACTG1发生错义突变而引起。本文就BWS患者中感音神经性聋相关基因突变位点的研究进展进行探讨,以期为遗传性耳聋患者的病因诊断提供一定价值与帮助。     

SLC26A4基因突变与听力表型的关系

SLC26A4是导致前庭导水管扩大的主要责任基因。该基因突变引起的听力损失多为感音神经性聋,也可为传导性或混合性聋,听力损失程度多为重度或极重度,听力曲线类型主要表现为高频下降型,也可表现为上升型、平坦型、W型及岛型。本文将SLC26A4基因突变与听力表型的关系进行文献综述,可为临床耳聋基因诊断和遗传咨询提供参考。     

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...     

KCNQ4基因突变对常染色体显性遗传性聋家系的影响

目的 应用选基因法了解KCNQ4基因对中国耳聋家系的影响，检测其突变形式。方法 在一个6代相传的常染色体显性遗传性家系中，应用聚合酶链反应－单链构像多态性（polymerase chain reaction-single strand conformation polymorphism,PCR-SSCP)及克隆测序方法对KCNQ4基因的全部编码序列的PCR产物进行突变位点及多态序列检测。结果 在该家系中，对36位家系成员进行了KCNQ4基因的编码序列的检测，发现KCNQ4基因外显子2的分子多态现象，经测序分析证明这种多态是由于内含子中47个碱基复制数的差异所造成的。结论 本实验证明KCNQ4基因外显子2的编码区附近存在一个新的分子多态标记，这种分子多态表现出不同的基因型。通过对这些基因型与耳聋表型的相关分析发现，随着内含子复制数的增加，耳聋表现度明显增加。提示KCNQ4基因外显子2与外显子3之间内含子复制数的变化可能是这个家系出现耳聋的一种特征性分子标记。     

KCNQ4基因突变对常染色体显性遗传性聋家系的影响

目的应用候选基因法了解KCNQ4基因对中国耳聋家系的影响,检测其突变形式. 方法在一个6代相传的常染色体显性遗传性聋家系中,应用聚合酶链反应-单链构像多态性(polymerase chain reaction-single strand conformat io n polymorphism,PCR-SSCP)及克隆测序方法对KCNQ4基因的全部编码序列的PCR产物进行突变位点及多态序列检测. 结果在该家系中,对36位家系成员进行了KCNQ4基因的编码序列的检测,发现KCNQ4基因外显子2的分子多态现象,经测序分析证明这种多态是由于内含子中47 个碱基复制数的差异所造成的. 结论本实验证明KCNQ4基因外显子2的编码区附近存在一个新的分子多态标记,这种分子多态表现出不同的基因型.通过对这些基因型与耳聋表型的相关分析发现,随着内含子复制数的增加,耳聋表现度明显增加.提示KCNQ4基因外显子2与外显子3之间内含子复制数的变化可能是这个家系出现耳聋的一种特征性分子标记.     

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.     

Audiologic evidence for further genetic heterogeneity at DFNA2

A large American family has been mapped to the DFNA2 locus. However, mutation screening of CX31 and KCNQ4, the two genes associated with deafness at this locus, did not identify any mutations. The purpose of this report was to characterize the otologic and audiometric phenotype of this large American family with non-syndromic, autosomal-dominant sensorineural hereditary hearing impairment (HHI). Anamnestic data were obtained, pure-tone audiometry was performed and transient-evoked otoacoustic emissions were recorded. The findings in affected family members were compared to those in unaffected family members and to the respective p50 thresholds of the normal age-matched population. Mutational analysis of the CX26 gene was also performed. The affected members of this family demonstrated progressive symmetric sensorineural hearing impairment. The hearing loss was downward sloping, with mild-to-moderate loss in the low and mid frequencies and severe-to-profound loss in frequencies > 4,000 Hz. The onset of disease was predominantly in the first or early in the second decade. Hearing impairment progressed at approximately 1 dB per year across all frequencies. Transient-evoked otoacoustic emissions revealed a minimal response over all frequencies in affected members but robust responses in all unaffected members. Mutation in the CX26 gene was not present. The affected frequencies observed in this family were similar to those in the original family mapped to DFNA2; however, the age of onset of disease was different and the hearing loss progressed at a slower rate. Therefore, this family provides clinical evidence of genetic heterogeneity at the DFNA2 locus and can serve as a model for age-related hearing loss.     

Speech recognition scores related to age and degree of hearing impairment in DFNA2/KCNQ4 and DFNA9/COCH

OBJECTIVE: To analyze the relationship between pure-tone hearing threshold and speech recognition performance in DFNA2/KCNQ4 and DFNA9/COCH, 2 types of high-frequency nonsyndromic hearing impairment. DESIGN: Case series with cross-sectional analysis of phoneme recognition scores related to age and hearing level. SETTING: University hospital. PATIENTS: Forty-five members of 4 separate families, all carrying 1 of 3 different mutations in the KCNQ4 gene at the DFNA2 locus (1p34); 42 members of 7 separate families, all carrying the same Pro51Ser mutation in the COCH gene at the DFNA9 locus (14q12-q13). RESULTS: The deterioration of speech recognition dropped to a 90% score at a higher level of hearing impairment (pure-tone-average at 1, 2, and 4 kHz) in DFNA2-affected patients (65 dB) than in DFNA9-affected patients (46 dB). CONCLUSION: At similar levels of hearing impairment, DFNA2/KCNQ4-affected patients showed better speech recognition performance than DFNA9/COCH-affected patients.     

江苏南通地区非综合征性耳聋GJB2基因突变分析

目的 研究南通地区非综合征性耳聋GJB2基因突变情况。方法 收集南通地区海安县和如皋县聋哑学校学生100名和健康对照组50名，利用PCR扩增及限制性内切酶酶切分析初筛GJB2 235delC突变者，然后再行DNA直接测序。结果 耳聋组中共发现三种突变：235delC、176—191del16、299—300delAT。235delC是主要突变方式．约30％的患者携带此突变；299—300delAT和176-191del16突变检出率分别为9％和8％。对照组未发现这些突变。结论 南通地区非综合征性耳聋GJB2基因突变率较高，因此在南通地区进行广泛的生育前耳聋基因筛查工作有重要意义。     

Mitochondrial deafness

The last decade has led to the identification of several mitochondrial DNA mutations associated with hearing loss. Since the only known function of the human mitochondrial chromosome is to participate in the production of chemical energy through oxidative phosphorylation, it was not unexpected that mitochondrial mutations interfering with energy production could cause systemic neuromuscular disorders, which have as one of their features hearing impairment. Surprisingly, however, inherited mitochondrial mutations also have been found to be a cause of non-syndromic hearing loss, and predispose to aminoglycoside induced hearing loss, while acquired mitochondrial mutations have been proposed as one of the causes of presbycusis. After a brief review of mitochondrial genetics, we will outline the different mitochondrial mutations associated with hearing loss, describe the audiological features, and discuss the clinical relevance of diagnosing these mutations. Clinical expression of these mitochondrial mutations is dependent on environmental exposures and nuclear-encoded modifier genes. Preventive and therapeutic strategies will depend on identification and avoidance of the environmental exposures, and the identification of the nuclear-encoded modifier genes. Experimental approaches to identify these modifier genes will be presented.     

均衡噪声阈值检测法研究耳蜗死区在感音神经性聋患者耳蜗中的分布

目的探讨在感音神经性聋患者中是否存在耳蜗死区及其分布情况。方法采用均衡噪声阈值检测法检测82例(130耳)感音神经性聋患者和25例(50耳)正常听力者是否存在耳蜗死区,并比较耳蜗死区与性别、年龄、耳别、听力损失程度以及病程的关系。结果 82例感音神经性聋患者中有41.46%(34/82)存在耳蜗死区,正常听力者中无耳蜗死区,两者差异具有统计学意义(P<0.01)。耳蜗死区的存在在性别、年龄和耳别之间无明显差异,而不同听力损失程度、病程的感音神经性聋患者耳蜗死区的检出率差异有统计学意义(P<0.05),听力损失越重,病程越长,检出率越高。33.85%(44/130)受试耳存在耳蜗死区,其中高频区耳蜗存在死区者占23.08%(30/130),低频区耳蜗存在死区者占2.31%(3/130),高低频区同时存在耳蜗死区者占8.46%(11/130),高频耳蜗死区检出率远高于低频区。结论在感音神经性聋患者存在耳蜗死区中,耳蜗死区的存在与听力损失程度及病程有关,听力损失程度越重、听力受损时间越长,存在耳蜗死区的可能性越大。     

赤峰市特教学校重度感音性聋分子病因学分析--GJB2 235delC突变和线粒体DNA 12SrRNA A1555G突变筛查报告

目的 调查内蒙古赤峰市聋哑学校重度感音性耳聋病因学情况。方法 对赤峰市聋哑学校140名学生进行耳聋病因问卷调查、纯音听阈测试。所有受检学生均采集外周血并提取DNA．进行线粒体DNA 12SrRNA A1555G点突变检测、GJB2基因突变检测。结果 1例（0．71％）存在线粒体DNA A1555G点突变；16例（11．43％）存在GJB2 235delC纯合突变，19例（13．57％）存在GJB2 235delC杂合突变。结论 赤峰市耳聋患者存在较高的遗传性耳聋发生率，并呈现明显的地域特点。通过聋病分子诊断，可达到防聋、指导聋儿康复及评估耳聋预后等积极效果。