氨基糖甙类抗生素致聋家系线粒体DNA1555G点突变分析

目的考察１５５５Ｇ点突变与氨基糖甙类抗生素致聋的对应关系，建立相应的基因诊断方法提供依据。方法收集了３个有明确氨基糖甙类抗生素应用史的母系遗传耳聋家系１３人（包括聋人和听力正常者）的外周静脉血标本，聚合酶链反应扩增线粒体ＤＮＡ，Ａｌｗ２６Ｉ限制性内切酶分析、ＤＮＡ斑点杂交和ＤＮＡ序列分析检测１５５５Ｇ点突变。结果家系１和３的７份样品均为１５５５Ｇ点突变阳性，家系２的６份样品为１５５５Ｇ点突变阴性。结论发现１个１５５５Ｇ点突变阴性的氨基糖甙类抗生素致聋家系，说明线粒体ＤＮＡ１５５５Ｇ点突变不是氨基糖甙类抗生素遗传易感性唯一的分子基础。     

氨基糖甙类抗生素致聋家系线粒体DNA A1555G突变分析

目的 研究线粒体12S rRNA基因A1555G点突变与氨基糖甙类抗生素致聋遗传易感性的关系，为建立相应的基因诊断方法提供依据。方法 收集了五个有明确氨基糖甙类抗生素应用史的耳聋家系共23名成员的外周静脉血标本，从白细胞中提取DNA，PCR扩增线粒体DNA片段，限制性内切酶分析和DNA序列分析检测A1555G点突变。结果 五个家系有母系血缘关系的18份样品均为A1555G点突变阳性，5名配偶为A1555G点突变阴性。结论 线粒体DNA A1555G点突变是氨基糖甙类抗生素致聋遗传易感性最主要的原因，检测A1555G点突变对氨基糖甙类抗生素致聋遗传易感性的预测有重要意义。     

线粒体DNA1555位点突变、非综合征性聋与氨基糖甙类抗生素关系研究

氨基糖甙类抗生素致聋是导致儿童重度感音神经性聋的主要原因，而且具有家族聚集性与易感性。目前认为线粒体DNA1555位点突变是导致氨基糖甙类所致非综合征聋的主要遗传基础。本文试图从线粒体基因1555位点突变结构特点、发病机理、突变的外显率、临床意义等方向作一综述。     

线粒体DNA突变与氨基糖甙类抗生素致聋研究进展

线粒体脱氧核糖核酸（mitochondrial deoxyroibose nucleic acid,mtDNA）是唯一存在于核外的遗传物质,具有独特的遗传特性,如严格的母系遗传、具有半自主性、不与组蛋白结合,修复能力低下,容易发生碱基突变。氨基糖甙类抗生素耳聋具有家族聚集的现象,遗传的线粒体突变是氨基糖甙类抗生素致聋（aminoglycoside antibiotics induced deafness,AAID）等非综合征耳聋的原因之一。     

氨基糖甙类抗生素致聋家系线粒体DNA12S和16S rRNA基因突变分析

目的 研究线粒体rRNA基因突变与氨基糖甙类抗生素致聋遗传易感性的关系，为建立相应的基因诊断方法提供依据。方法 收集了五个有明确氨基糖甙类抗生素应用史的耳聋家系共27名成员的外周静脉血标本。从白细胞中提取DNA，PCR扩增线粒体DNA片段。Alw26I限制性内切酶分析和DNA序列分析检测A1555G点突变，并对其中一个家系进行了线粒体DNAl2S和16SrRNA基因的全序列分析。结果家系A．C．D和E的2l份样品均为A1555G点突变阳性，家系B的6份样品为A1555G点突变阴性。家系B线粒体DNAl2S和16SrRNA基因全序列分析显示该家系存在16SrRNA基因第2227位“AA”插入突变。结论 本研究发现了一个A1555G点突变阴性的氨基糖甙类抗生素致聋家系，说明线粒体DNA A1555G点突变不是氨基糖甙类抗生素遗传易感性唯一的分子基础，对氨基糖甙类抗生素致聋遗传易感性的预测仅检测A1555G点突变是不够的。应与mtDNA其它相关突变位点的检测结合起来。     

氨基糖甙类抗生素中毒聋易感性与线粒体DNA突变的研究

应用PCR-限制性内切酶酶切片段长度多态性技术,对164例过去应用过氨基糖甙类药物目前听力严重下降的患者外周血线粒体DNA进行了研究。结果发现6例聋哑患者线粒体DNA12srRNA基因1555位点发生了点突变,突变率3．6％,100例听力正常人无一例在此位点有突变。我们对国外学者的研究方法加以改良,使结果更容易判断。我们推测在线粒体DNA上还有其它与中毒聋易感性相关的突变位点尚未被发现。     

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.     

一个氨基糖甙类药物致聋家系线粒体DNA全序列分析

目的 评估线粒体单倍型对一个氨基糖甙类药物致聋家系中12S rRNA A827G突变表型的影响.方法 用基因组DNA抽提试剂盒提取外周血DNA,PCR扩增家系成员mtDNA 12S rRNA基因进行A827G突变的测序验证,对携带A827G突变的家系先证者进行mtDNA全序列PCR扩增和测序分析,结果 与修正的剑桥参考序列比对,识别除A827G以外的突变位点.结果 5名母系成员mtDNA 12S rRNA序列分析均检测到A827G突变.与修正的剑桥参考序列及家系配偶相比,先证者的mtDNA全序列分析显示出独特的多态性改变,除已知的12S rRNAA827G突变外,另检测到24个碱基变异,其中12S rRNA基因A783C、G786C以及ND4基因C11720A突变(L319A)为首次发现.系统进化法分析显示,上述多态性位点均位于mtDNA非保守区域.结论 线粒体单倍型对该家系mtDNA A827G突变的表型表达无明显影响.     

氨基甙类抗生素耳毒性与线粒体基因突变分析

进一步证明遗传因素对氨基甙类抗生素耳毒性的作用,探讨该病的发病机理。方法应用ＰＣＲ限制性酶切方法分析了９个氨基甙类抗生素致聋家系中６２个成员线粒体ＤＮＡ。结果发现５个家系中２０例线粒体ＤＮＡ２２ＳｒＲＮＡ基因第１５５５位Ａ→Ｇ点突变。结论该突变是氨基甙类抗生素耳毒性遗传易感性的分子生物学基础。可能有其他他粒体ＤＮＡ基因突变与氨基甙类抗生素耳毒性有关。     

线粒体DNA缺失突变在氨基糖甙类抗生素耳毒易感中的作用

目的　建立大鼠线粒体DNA(mitochondrialDNA ,mtDNA)缺失突变模型 ,探讨mtDNA缺失突变在氨基糖甙类抗生素 (aminoglycosideantibiotics,AmAn)耳毒易感性中的作用。方法　取Wistar大鼠随机分为A、B两组 ,每组 15只。其中A组大鼠以皮下注射阿霉素 (doxorubicin ,DOX) 2mg/kg体重 ,每周 2次共 3个月 ,B组则以生理盐水取代DOX。然后A、B组均连续腹腔注射卡那霉素(kanamycin ,KM)每日 5 0 0mg/kg体重共 10d。用药前、后测试听性脑干反应 (auditorybrainstemre sponse,ABR)阈 ,并用聚合酶链反应 (polymerasechainreaction ,PCR)技术对大鼠内耳膜迷路mtDNA 4834bp缺失突变进行检测。结果　①A、B两组大鼠用KM前、后 ,ABR反应阈提高 ,均值 ( x±s)分别为(6 7 0 8± 8 5 9)dBpeSPL和 (12 71± 4 42 )dBpeSPL ,二组均数间差异有显著性意义 (P <0 0 1) ;②大鼠内耳组织mtDNA检测发现 :A组有 9/15只存在 4834bp片段缺失 ,而在B组未检测到 4834bp片段缺失。结论　DOX可诱导大鼠内耳组织mtDNA缺失突变。大鼠内耳组织mtDNA缺失突变可增加其对AmAn耳毒作用的敏感性。     

线粒体DNA突变致聋家系检测及单倍型分析

目的 探讨母系遗传氨基糖甙类抗生素诱发致聋家系的线粒体DNA突变情况及其单倍型背景.方法 收集贵州遵义地区6个母系遗传非综合征性耳聋家系的临床资料及血液样本,经PCR-RFLP(polymerase chain re-action-restriction fragment length Polymorphism,聚合酶链反应-限制性片段长度多态)及测序技术检测线粒体DNA1555G突变,并通过对各家系线粒体DNA高变区序列测定及编码区限制性片段多态性分析以划分单倍型类群.结果 经酶切及测序证实其中4个家系存在线粒体DNA 1555G突变,分别属于A、D6、G及M*单倍型.结论 该地区线粒体DNA 1555G突变引起氨基糖甙类抗生素高度敏感致聋的家系发生率较高,线粒体DNA1555G突变致聋家系呈现不同的线粒体单倍型类型.     

非综合征型耳聋患者mtDNA A1555G异质性突变比例与临床表型的关系

目的定量检测非综合征型耳聋患者线粒体DNA(mitochondrial DNA,mtDNA)1555突变型/野生型的拷贝数,探讨突变型/野生型比例与临床表型之间的关系。方法建立实时定量PCR技术和扩增阻滞突变系统(Real-time quantitative PCR和Amplification refractory mutation system,RT-ARMS-qPCR系统)对含突变型和野生型mtDNA 1555位点的拷贝数进行定量检测并计算比例。共检测散发组12例、家系组7例异质性突变患者,结合耳聋患者的临床资料,分析突变型与野生型的比例与耳聋严重程度的关系。结果散发组mtDNA A1555G异质性突变的患者中,突变型mtDNA所占的比例与耳聋轻重程度相关(r=0.771,P=0.003);家系组患者中,突变型mtD-NA所占的比例亦与耳聋轻重程度相关(r=0.850,P=0.015)。结论突变型mtDNA占所有mtDNA的比例与耳聋的严重程度密切相关,是非综合征型耳聋临床表型多样性的分子基础。     

Deafness due to A1555G mitochondrial mutation without use of aminoglycoside

OBJECTIVES/HYPOTHESIS: The objective was to clarify the characteristics of deafness associated with the A1555G mutation within mitochondrial 12S ribosomal RNA gene in the absence of aminoglycoside exposure. STUDY DESIGN: Clinical and genetic studies in family members with the A1555G mitochondrial mutation were performed. METHODS: The subjects were 123 maternally related members of a large Japanese family with the A1555G mutation. All subjects had no previous history of exposure to aminoglycosides. Hearing disability and handicap, tinnitus, and medical histories were analyzed by interviews in all of the subjects, genetic testing was performed in 41 subjects, and pure-tone audiometry was conducted in 26 subjects with hearing disability and handicap. RESULTS: The A1555G mutation was detected in a homoplasmic form (meaning that all the mitochondrial DNA carries the mutation) in all 41 subjects who were screened. The risk for developing postlingual hearing loss was likely to be much higher in the present subjects than in the general population. Both the severity and age at onset of the phenotype were similar in affected subjects within the same sibling group. Pure-tone averages were significantly worse in subjects who developed hearing loss before age 10 years than in those who developed hearing loss later. CONCLUSION: The present study demonstrated that the prevalence of deafness in individuals with the A1555G mitochondrial mutation was likely to be high even in the absence of aminoglycoside exposure and clearly showed the association of severe to profound hearing loss with the onset of hearing loss before age 10 years.     

Sensorineural hearing loss and the 1555G mitochondrial DNA mutation

Recent studies have identified a mitochondrial DNA mutation (1555G) which causes sensorineural hearing loss (SNHL). In many cases deafness follows exposure to aminoglycoside antibiotics, the 1555G mutation sensitizing the inner ear to these drugs. The 50 cases reported to date are discussed, as are the possible mechanisms behind the pathogenesis of this mutation. This finding in families from a wide range of ethnic backgrounds suggests that the 1555G mutation is one of the more common genetic causes of SNHL and provides a fascinating example of how a genetic mutation interacts with an environmental factor with harmful effect.     

Audiological features and mitochondrial DNA sequence in a large family carrying mitochondrial A1555G mutation without use of aminoglycoside

To elucidate the pathophysiological and genetic mechanisms of hearing loss associated with the homoplasmic mitochondrial A1555G mutation in the absence of aminoglycoside exposure, we conducted audiological and genetic analyses on 67 maternally related members of a large Japanese family carrying this mutation. A consistent pattern was evident in the audiograms, with features of sensory presbycusis, cochlear origin at all levels of hearing loss, and a high degree of vulnerability of outer hair cells. That the degree of hearing loss was similar in affected subjects within the same sibling group but differed between sibling groups suggests the involvement of nuclear modifier genes. Total mitochondrial DNA sequences were completely identical among subjects with various levels of hearing loss, and lacked additional pathogenic mutations. For the diagnosis of sensorineural hearing loss, the mitochondrial A1555G mutation should be considered when these features are present even in the absence of aminoglycoside exposure.     

无综合征耳聋与线粒体DNA1555^A→C突变

目的：分析４个无综合征耳聋家系是存在线粒体ＤＮＡ１５５５＾Ａ→Ｃ的突变。方法：以ＰＣＲ－ＲＦＬＰ方法进行线粒体ＤＮＡ１５５５＾Ａ→Ｃ突变筛查。结果 仅１个无综合征耳聋家系中的５个成员有４个存在该突变。结论：线粒体ＤＮＡ１５５５＾Ａ→Ｃ点突变与部分无综合征耳聋有一定关系。