线粒体DNAA1555G突变筛查在药物性耳聋预防和康复中的作用探讨

目的通过调查16个由线粒体DNA（mtDNA）A1555G突变导致的非综合征性感音神经性耳聋家系母系家庭成员耳聋的发病状况,分析在敏感人群中进行mtDNAA1555G突变基因筛查在预防药物性耳聋以及指导耳聋康复和治疗过程中的必要性。方法应用自主研制的线粒体DNAA1555G突变检测试剂盒筛查出16个mtDNAA1555G突变阳性个体,并对这些个体进行详细的家系分析,了解阳性病例所有母系家庭成员的听力状况,绘制详细家庭系谱图,对母系成员中未发病者进行耳聋预防和康复宣教。结果16例耳聋病例中均存在mtDNAA1555G突变,在家系调查中发现,存活母系家庭成员239人,耳聋发病19人（含先证者）,未发病220人。结论在耳聋人群中进行mtDNAA1555G突变基因筛查发现氨基糖甙类抗生素（AmAn）致聋敏感个体,进而对其未发病母系家庭成员进行防聋宣教是预防药物性耳聋发生、降低药物性耳聋发生率的有效措施,同时对于已经耳聋的敏感个体,明确其发病的原因也是指导其康复、避免听力恶化的重要环节。     

Prevalence of the mitochondrial A 1555G mutation in Moroccan patients with non-syndromic hearing loss

Mutations in mitochondrial DNA (mtDNA), especially the A1555G transition in the 12S rRNA gene, are one of the causes of both aminoglycoside-induced and non-syndromic sensorineural hearing loss.

Objective

The aim of this study was to determine the prevalence of the A1555G mitochondrial mutation in Moroccan patients.

Methods

We performed molecular characterization by PCR-RFLP and direct sequencing of one hundred and sixty four patients (84 unrelated familial and 80 sporadic cases) with a congenital sensorineural non-syndromic hearing loss and one hundred normal hearing controls for the occurrence of the A1555G mutation.

Results

Mutational analysis of the mtDNA showed the presence of the homoplasmic A1555G mutation in three families, leading to a frequency of 3.6% similar to that reported for European-populations. No A1555G mutation was detected in sporadic and controls cases. However, we detected in twenty normal hearing controls a novel polymorphism A1557C, which was not found in patient samples. We further evidenced the presence of the A1438G mitochondrial polymorphism in four patients with sensorineural hearing loss and in five controls.

Conclusion

Our results show that the occurrence of the A1555G mutation in hearing impaired patient's accounts for 3.6% in a Moroccan patients and those novel mtDNA polymorphisms might contribute to a novel sub-haplogroup specific of the Magrheb.     

非综合征型聋患者线粒体DNA A1555G突变频率分析

目的分析甘肃地区非综合征型聋患者线粒体DNA 12SrRNA A1555G的突变频率。方法收集甘肃地区五所聋哑学校802例聋哑学生血样，经基因组DNA提取后进行聚合酶链反应（polymerase chain reaction，PCR）扩增线粒体DNA目的片段，用A1w26I限制性内切酶检测A1555G点突变，对酶切阳性病例的PCR产物纯化后进行直接测序验证酶切结果，分析线粒体DNA 12SrRNA A1555G在甘肃地区的突变频率。结果802例聋哑学生中有67例经酶切及直接测序证实为线粒体DNA A1555G突变，突变频率为8．4％（67／802）。其中有15例母系家庭成员中还有2例以上耳聋患者。结论线粒体DNA 12SrRNA A1555G点突变在甘肃地区非综合征型聋患者中占有很高的比例，高于国内外其他地区的相关报道。此研究结果不仅为绘制中国人群线粒体DNA A1555G突变频谱增添新的内容，也为因地制宜地开展耳聋基因诊断、实施遗传咨询及积极预防耳聋的发生有重要的指导意义。     

湖北地区306例极重度聋患儿基因芯片筛查分析

目的：通过检测湖北地区极重度感音神经性聋患儿常见耳聋基因突变情况,分析该人群的分子病因学特点,为临床耳聋防治和遗传咨询提供参考。方法：收集306例湖北地区极重度感音神经性聋患儿,抽取外周血,提取DNA,应用遗传性耳聋基因芯片检测GJB2、GJB3、SLC26A4和线粒体12SrRNA4个基因的9个突变热点。对所有携带SLC26A4基因突变患者进行颞骨CT扫描。结果：306名患儿中,132例（43．14％）检出携带不同基因突变,其中有2例携带双基因突变。GJB2基因突变检出率为29．41％（90／306）,SLC26A4基因突变检出率为13．72％（42／306）,线粒体12SrRNA基因突变检出率为O．65％（2／306）。本组患者未检出GJB3基因突变。36例携带SLC26A4基因突变者颞骨CT扫描显示前庭水管扩大。结论：GJB2基因和SLC26A4基因是本组患儿最主要的致聋基因,其中235delC突变为最常见的突变位点,其次为1VS7—2A〉G突变。筛查SLC26A4基因常见突变有助于大前庭水管综合征的诊断。     

Prevalence of A1555G mitochondrial mutation in Chinese newborns and the correlation with neonatal hearing screening

Objective

To investigate the feasibility of genetic screening for deafness causative genes in the process of newborn hearing screening in China.

Methods

Total 865 newborn babies between November 2009 and March 2010 were enrolled for the simultaneous hearing and deafness causative gene screening in Tongji Hospital, Wuhan, China. Hearing screening followed a two-stage strategy with transient evoked otoacoustic emissions. Infants referred after the second-stage screening were tested by diagnostic auditory brainstem response (ABR). Genomic DNA was extracted from heel blood of newborns, and the mitochondrial 12S rRNA A1555G mutation was detected by polymerase chain reaction (PCR) based restriction fragment length polymorphism and confirmed by DNA sequencing.

Results

In hearing screening, 134 out of the 865 newborns (15.5%) were referred after the first-stage screening and 86.6% (116/134) of them returned for the second stage. After the second-stage screening, 15 who were still referred were tested by diagnostic ABR and 3 of them failed the test. On the other hand, gene screening identified 6 of the 865 newborns (0.7%) harbored homoplasmic 12S rRNA A1555G mutation although they passed the hearing screening.

Conclusion

It might be practical and effective to complement routine hearing screening in newborns with gene screening for the purpose of early diagnosis and discovery of the late-onset hearing loss.     

Bilateral sensorineural hearing loss in members of a maternal lineage with a mitochondrial point mutation

Pure-tone audiometry was carried out on members of a recently described maternal lineage with sensorineural deafness, harbouring a novel mitochondrial mutation in the gene for tRNA-ser(UCN). This revealed a characteristic pattern of symmetrical bilateral sensorineural hearing losses in each affected individual, predominantly affecting the high-frequencies, but with considerable variability between individuals. No clear correlation was observed between age and severity, but most subjects reported progressive worsening of their condition. Some members of the lineage were found to be heteroplasmic for the tRNA-ser(UCN) mutation. However, the severity of hearing loss was poorly correlated with the representation of the mutant mtDNA, indicating that other, as yet unidentified factors must be involved in the aetiology of this disorder.     

新疆维吾尔族非综合征型遗传性聋患者线粒体DNA 12SrRNA A1555G突变分析

目的:调查新疆地区维吾尔族非综合征型遗传性聋患者的线粒体DNA 12SrRNA A1555G突变情况,为预防氨基苷类抗生素致聋提供依据。方法:收集新疆地区51例维吾尔族非综合征型遗传性聋患者,53例维吾尔族听力正常者作为对照组。抽取外周静脉血,从白细胞中提取DNA,PCR扩增线粒体DNA目的片断,Alw26I限制性内切酶检测A1555G点突变,而后对阳性患者的PCR产物进行DNA测序验证。结果:在所有样本中,2例存在线粒体DNA A1555G点突变,均为维吾尔族非综合征型遗传性聋患者,且均有明确氨基苷类抗生素用药史。结论:新疆地区维吾尔族耳聋患者及维吾尔族正常人线粒体DNA A1555G检出率比较差异无统计学意义。携带有该突变的个体对氨基苷类抗生素的耳毒作用有高度易感性。新疆地区聋哑患者的A1555G突变检出率低于全国平均水平。     

GJB2 and mitochondrial DNA 1555A>G mutations in students with hearing loss in the Hubei Province of China

Objectives

The GJB2 and MTRNR1 1555A > G mutations are the prevalent causes of hearing loss worldwide. However, the mutation profiles of the two genes are dependent on the ethnic or geographic origins. Therefore, this study was to characterize the forms and frequencies of the two genes in 813 students with hearing loss in Hubei province, Central China.

Methods

Blood samples from 813 students were obtained with informed consent. Genomic DNA was extracted from peripheral blood leukocytes. The target fragments were amplified by polymerase chain reaction (PCR). Sequencing (or enzyme digestion) was applied to identify sequence variations.

Results

Ten different mutations were identified in GJB2 in 146 of the 813 (17.96%) patients and 11.81% (96/813) patients had homoplasmic mtDNA 1555A > G mutation.

Conclusions

This study demonstrated the high prevalence of GJB2 and mtDNA 1555A > G mutations in Central Chinese population. Therefore, it will be effective to perform GJB2 and mtDNA 1555A > G mutation analysis for genetic screening for hearing loss in this population.     

Cochlear implantation in a patient with profound hearing loss with the A1555G mitochondrial DNA mutation and no history of aminoglycoside exposure

The A1555G mitochondrial deoxyribonucleic acid (mtDNA) point mutation has classically been associated with sensorineural hearing loss in patients following aminoglycoside exposure. More recently, the mutation has been implicated in sensorineural hearing loss in patients without previous aminoglycoside use. In addition, cochlear implantation has been shown to be effective in the group of patients with prior aminoglycoside exposure but, to date, no case of cochlear implantation in a patient with the A1555G mutation and no prior exposure to aminoglycosides has been explicitly described in the literature. We report the case of an 80-year-old woman with the A1555G mtDNA mutation, a 35-year history of bilateral progressive hearing loss and no history of aminoglycoside exposure who underwent successful implantation of a Nucleus 24 Contour device at our institution. Post-operatively, the patient exhibited marked improvement in tests of auditory performance. We conclude that cochlear implantation can be an effective method to restore some sense of hearing in patients with the A1555G mtDNA mutation and sensorineural hearing loss.     

河北涿州、高碑店市特教学校非综合征性聋分子病因学分析——GJB2 235delC突变、SLC26A4 IVS7-2A＞G突变和线粒体DNA12SrRNA A1555G突变筛查报告

目的 对河北涿州、高碑店地区重度耳聋患者进行分子流行病学调查，了解耳聋的常见分子病因。方法 对河北涿州、高碑店市特殊教育学校64名耳聋学生进行遗传性耳聋问卷调查、全面的体格检查、耳鼻咽喉专科检查以及听力学评估（包括纯音测听和声导抗）。对64名非综合征型感音神经性耳聋患者分别进行GJB2基因235delC突变、线粒体DNA 12SrRNA基因A1555G点突变的限制性内切酶分析。应用直接测序法检测SLC26A4基因IVS7—2A〉G突变。结果7例（10．93％）携带GJB2基因235delC纯合突变；9例（14．06％）携带GJB2基因235delC杂合突变；6例（9．37％）携带SLC26A4基因ⅣS7—2A〉G纯合突变，12例（18．75％）携带SLC26A4基因IVS7—2A〉G杂合突变：未发现携带线粒体DNA 12SrRNA基因A1555G点突变者。结论 河北涿州、高碑店地区非综合征型耳聋患者存在较高的GJB2基因235delC和SLC26A4基因ⅣS7—2A〉G突变发生率，而线粒体DNA 12SrRNA基因A1555G突变发生率低于全国平均水平。聋病分子流行病学调查提示河北涿州、高碑店地区20.3％的非综合征型耳聋患者在分子水平能够明确诊断．另有32．81％的患者有遗传倾向。进行准确的耳聋早期诊断、遗传咨询、及时干预和治疗在这一地区的聋哑人群中非常重要。     

佛山地区耳聋儿童GJB2 235delC突变和线粒体DNA A1555G突变的研究

目的研究佛山地区先天性聋儿中GJB2突变和线粒体DNAA1555G突变在耳聋发病中的作用。方法收集180例散发的先天性聋儿的DNA，利用聚合酶链反应一限制性片断长度多态性（PCR—RFLP）方法和Prey—DAF药物性耳聋基因诊断试剂盒对收集到的DNA进行分析，筛查患者GJB2235deIC突变和线粒体DNAA1555G突变。结果经PCR-RFLP和Prev—DAF药物性耳聋基冈诊断试剂盒分析，在所有参加检测的180名患儿中共发现GJB2235delC纯合突变14名（7．78％），GJB2235delC杂和突变7名（3．89％），线粒体DNAA1555G突变6名（3．33％）。结论应用基因检测方法可以在地区性耳聋流行病学凋查中帮助明确常见的遗传性耳聋病例，并可指导此类患者的家庭进行耳聋的预防。     

A mutation in Wolfram syndrome type 1 gene in a Japanese family with autosomal dominant low-frequency sensorineural hearing loss

Conclusion. Our findings suggest that Wolfram syndrome type 1 gene (WFS1) mutation is an important cause of autosomal dominant low-frequency sensorineural hearing loss (LFSNHL) in Japan. Objective. DFNA6/14 is caused by a heterozygous mutation of WFS1 and is a common cause of autosomal dominant LFSNHL among populations in both Europe and the US. The purpose of this study was to investigate WFS1 mutations among Japanese patients whose phenotypes were consistent with those of DFNA6/14. Material and methods. Using audiometry and genetic analysis, we searched for WFS1 mutations in three unrelated Japanese patients with LFSNHL and a familial history of autosomal dominant hearing loss. Results. One patient carried a heterozygous G2700A mutation at codon 844 in exon 8, resulting in substitution of a threonine for an alanine (A844T). Genetic analysis of the available members of the patient's family showed that the A844T mutation segregated with LFSNHL, but was not detected in any of 140 control chromosomes. It thus appears likely that the A844T mutation is causative for hearing loss in this group. Speech audiometry, self-recording audiometry and auditory brainstem responses showed the patient to have cochlear deafness without retrocochlear dysfunction. No mutation was found in the other two patients.     

PCR-GeneScan法检测遗传性聋相关基因GJB2 235 delC和mtDNA A1555G突变

目的:检测GJB2 235delC杂合突变和mtDNA A1555G突变。方法:对120例样本进行诊断试验,其中测序GJB2 235delC杂合突变样本16例,mtDNA A1555G突变17例。用PCR方法对目标片段进行扩增,PCR产物在3100DNA sequencer(ABI)上聚丙烯酰胺胶毛细管电泳,GeneScan、GeneMarker软件数据分析。结果:120例样本均得到检测结果,检出GJB2 235delC杂合突变样本17例,mtDNA A1555G突变17例,1例正常样本误诊为235delC杂合突变而出现假阳性。结论:PCR-GeneScan技术可以同时检测2种不同基因的突变,单管多重PCR和GeneScan荧光标记法结合是同时检测多种突变一种新的思路,而且可能是一种有效的方法。     

GJB2, SLC26A4, and mitochondrial DNA12S rRNA hot-spots in 156 subjects with non-syndromic hearing loss in Tengzhou,China

Conclusion: In this cohort of 156 non-syndromic hearing-impaired subjects of Tengzhou area, the most common deafness-associated genes GJB2, SLC26A4 and mtDNA 12S rRNA were investigated by SNPscan efficiently. GJB2 c.235delC and SLC26A4 c.IVS7-2A?>?G were the most common mutation sites. Objectives: Until now, there is no systematic gentic analysis in patients with non-syndromic hearing loss for Tengzhou area, so we evaluated the molecular etiology to investigate the hot-sports. Methods: Peripheral blood samples were obtained from 156 patients with severe-to-profound non-syndromic deafness in Tengzhou. The SNP scan assay technique was performed for a rapid multiplex genetic screening to detect the 115 mutations of the most common three genes. All results were statistically analyzed with SPSS software. Results: Among the 156 analyzed patients, 60 patients were demonstrated with deafness genes, accounting for 38.46% (60/156), including GJB2 (22.44%, 35/156), SLC26A4 (13.66%, 22/156), and mtDNA 12S rRNA (2.56%, 4/156). In this study, we confirmed 23 deafness-causing mutations and 27 different allelic combinations including GJB2 (eight variants, 11 allelic combinations), SLC26A4 (13 variants, 16 allelic combinations) and mtDNA 12S rRNA (two variants). The occurrence rates of these deafness-causing mutations GJB2 c.235delC and SLC26A4 c.IVS7-2A?>?G were significantly higher than other mutation sites (p?相似文献   

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.     

淮阴A1555G突变相关耳聋核心家系成员的连接蛋白26基因突变分析

目的探讨连接蛋白26（connexin 26，Cx26）基因是否是江苏淮阴A1555G突变相关母系遗传聋家系的核修饰基因。方法采用聚合酶链反应一限制片断长度多态性分析（PCR—restriction fragment length polymorphism，PCR-RFLP）和测序技术，对江苏淮阴A1555G突变相关母系遗传非综合征型聋核心家系中的26例母系成员和62例对照（包括2例父系亲属、10例配偶对照和50例当地无关对照）的Cx26基因编码区序列进行了研究，并根据孟德尔遗传规律构建了家系成员Cx26基因的单体型图。结果在26例母系成员中共发现4处杂合性碱基变化，分别为79G→A、109G→A、341G→A和235delC。其中，前3种为已知多态性差异，而235delC为已知的可引起常染色体隐性聋的致病突变。但235delC突变仅存在于1例具有中度聋表型的母系成员和其2例听力正常的子女中，并不与耳聋表型共分离。而根据遗传规律，推测该突变来源于1例配偶对照，为外来突变；同时，根据4个位点变化构建的Cx26基因单体型图也未揭示Cx26基因与A1555G突变致聋有任何相关性；另外，在62例对照中也发现1例235delC杂合性缺失突变。结论235delC杂合性突变并不加重A1555G突变的致聋效应；Cx26基因也不是江苏淮阴母系遗传聋家系A1555G突变的核修饰基因。     

云南省10个非综合征性聋家系mtDNA 12S rRNA A1555G突变流行病学调查及分析

目的:探讨云南省10个非综合征性感音神经性聋家系的mtDNA 12SrRNA A1555G突变筛查、流行状况、遗传规律及对于特定药物干预预防的意义。方法:对10个家系以现场问卷方式调查母系家族耳聋的发病情况并绘制出详细的母系家系图,然后对自愿参与检测的母系成员采外周静脉血提取DNA,PCR扩增目的片段、限制性酶切检测A1555G突变阳性个体。结果:10个家系中参与采血者共96例,其中听力正常36例,感音神经性聋患者60例;经过筛查,4例无A1555G位点突变,92例(95.8%)有A1555G位点突变,其中7例为异质性表现,85例为均质性突变;73例有明确氨基苷类抗生素用药史,其余抗生素用药史不明确。结论:云南省药物性聋患者的比例较大,并且mtDNA 12SrRNA A1555G突变率高,对该地区进行mtDNA 12SrRNA A1555G突变筛查及药物干预预防宣教有重要意义。