两个线粒体12S rRNA C1494T突变及药物性耳聋家系的分子遗传学研究  

Molecular genetic characterization of two pedigrees with mitochondrial 12S rRNA C1494T mutation and aminoglycoside-induced hearing loss

作　　者：李海峰[1] 陈智斌[1] 邢光前[1] 

机构地区：[1]南京医科大学第一附属医院耳鼻咽喉科,江苏南京210029

出　　处：《南京医科大学学报（自然科学版）》2011年第5期720-726,共7页Journal of Nanjing Medical University(Natural Sciences)

基　　金：江苏省科教兴卫工程医学重点人才基金(RC2007064)

摘　　要：目的:探讨2个氨基糖甙类药物性耳聋及非综合征型耳聋家系的分子遗传学特征。方法:收集家系成员外周血样,常规方法提取基因组DNA。首先,利用基因芯片对中国人4个常见耳聋基因的9个突变热点进行分子筛查,9个位点分别为:GJB2基因的35 delG、176 del16、235 delC和299 delAT;GJB3基因的538 C>T;PDS基因的IVS7-2 A>G和2168 A>G以及mtDNA 12S rRNA基因的1494 C>T和1555 A>G。然后,对两家系的先证者分别进行线粒体DNA全序列及核基因TRMU和MTO1编码区的PCR扩增和测序分析。结果:芯片检测发现两家系的7名母系成员均存在同质性mtDNA 12S rRNA C1494T突变。与修正的剑桥参考序列相比,2名先证者的mtDNA全序列分析共检测到53个碱基变异,但除已知的12S rRNA C1494T突变外,其余52个碱基变异均为已报道的多态性位点;两家系先证者线粒体单体型分别是D4和D5a;TRMU和MTO1基因序列分析无异常发现。结论:线粒体DNA 12SrRNA C1494T突变是两个家系耳聋发生的主要分子基础,而氨基糖甙类抗生素的应用增强了该突变的表型表达;未能证实线粒体单体型以及核基因TRMU和MTO1对家系成员C1494T突变的表型具有修饰作用。Objective：To explore the molecular genetic characterization of two families with aminoglycoside-induced and nonsyndromic sensorineural hearing loss.Methods：Blood samples were obtained from 7 maternal members and 1 married-in spouse of the two families.Genomic DNA was extracted with conventional method.Firstly,9 hot spots for mutations in four most common pathologic genes,GJB2,GJB3,SLC26A4 and mitochondrial 12S rRNA,were screened with the DNA microarray to detect the deafness-associated mutations.The whole mitochondrial genomes and nuclear modifier genes TRMU and MTO1 of two probands were then PCR amplified and submitted for sequence analysis.Results：Mitochondrial 12S rRNA C1494T mutation was detected in all 7 maternal members of the two families.Sequence analysis of the complete mitochondrial genomes in two probands revealed the distinct sets of mtDNA polymorphism（52 other nucleotide changes）,in addition to the identical 12S rRNA C1494T mutation.None of these 52 variants,however,were shown to be pathogenic.The whole mitochondrial genome of proband from each of the two families was established that they belong to mitochondrial haplogroups D4 and D5a respectively.No mutations were identified in either TRMU gene or MTO1 gene.Conclusion：C1494T mutation in the mitochondrial 12S rRNA gene is the main molecular mechanism responsible for the hearing loss in the two pedigrees,and the use of aminoglycoside antibiotics may enhance the phenotypic manifestation of deafness-associated mitochondrial mutation.Mitochondrial haplogroups and nuclear genes（TRMU and MTO1）,however,seems not play a role in the phenotypic expression of C1494T mutation in these two families.

关 键 词：非综合征耳聋 线粒体DNA 基因突变 氨基糖甙类抗生素 

分 类 号：R394.3[医药卫生—医学遗传学]