Leber遗传性视神经病变的临床特点与基因突变相关性研究

发布时间：2018-03-20 09:56

本文选题：leber遗传性视神经病　切入点：线粒体DNA　出处：《郑州大学》2012年硕士论文　论文类型：学位论文

【摘要】：背景 Leber遗传性视神经病变(LHON)是一种严重危害青少年视功能的线粒体眼病,临床表现主要为双眼中心视力急性或亚急性减退,一般不伴眼球疼痛或压疼。视野检查显示中心暗点和旁中心暗点。LHON的流行病学调查显示,其在全世界的发病率为1／31000,在荷兰和芬兰的发病率分别为1／39000和1／50000。目前公认的LHON原发性致病位点有3个,分别是位于ND4区的G11778A位点,NDI区的G3460A位点和ND6区的T14484C位点,95%的LHON由以上三个原发致病突变位点中的一个所致。在我国其突变率分别为92.9%、1.4%和5.7%,G11778A突变最为常见,T14484C突变次之,G3460A突变罕见,该病散发病例较高,起病及病程多样化,在临床上极易出现漏诊或误诊,因此利用基因诊断筛查LHON患者,可以快速准确地筛查出突变位点,对于LHON的预防和治疗都有积极的意义。目的探讨中原地区LHON患者的线粒体DNA(mtDNA)突变类型及遗传特性,筛查中国人LHON患者新的继发位点。方法对189例LHON疑似病例(包括3个家系)首先进行眼科常规检查和脑部MRI检查,然后再分别应用等位基因特异性PCR(MSP-PCR),聚合酶链反应-限制性片段长度多态性(PCR-RFLP)和聚合酶链反应-单链构象多态性(PCR-SSCP)联合DNA测序的方法,对189例临床症状疑诊为LHON患者的G11778A,G3460A和T14484C3个原发位点进行mtDNA检测。对于缺乏3个原发突变位点的疑似患者,进行线粒体全基因组测序,寻找与疾病相关的其他继发突变位点。结果 1、在189例疑似LHON患者中,检测出86例为原发性突变G11778A,G3460A和T14484C3个致病位点中的一个。 2、在86例原发性突变中,3460位点突变6例,占7%；11778位点突变66例,占77%；14484位点突变14例,占16%。 3、在被检出的14例14484位点突变患者中,3例为单纯性14484原发位点突变,占22.2%,均为男性；5例14484原发位点合并14502继发位点突变,占33.3%,男1例,女2例；4例14484位点合并14470位点突变,占33.3%,男2例,女1例；2例14484位点合并14569位点突变,占11.1%。 4、通过对线粒体全基因组测序,发现A2706G,A1438G,T2115C,G3538T,G3834A,C4262A,C4275G,C7028T,G8392A,A10485G和C10719T这几个突变位点,在正常人当中,也存在以上部分位点突变现象。结论 1、中原地区LHON患者仍然以G11778A位点突变为主,其次为T14484C,G3460A突变最少见。 2、T14484C位点突变者当中,有单纯性14484位点突变者,有14484合并14502位点突变者,有14484合并14569位点突变者,有14484合并14470位点突变者,ND6区是线粒体DNA突变研究的热点之一。 3、通过对线粒体全基因组测序,发现一些新的继发突变位点可能对原发位点的致病起协同作用,具体作用如何还有待于进一步考证。
[Abstract]:Background. Leber's hereditary optic neuropathy (LHON) is a mitochondrial ophthalmopathy that seriously endangers the visual function of adolescents. The clinical manifestation is acute or subacute decrease of binocular central visual acuity. There is no pain or pressure in the eyeball. The visual field examination showed that the central dark spot and the paracentric dark spot. LHON epidemiological survey showed, It has an incidence of 1 / 31000 in the world, 1/39000 in the Netherlands and 1 / 50000in Finland. There are now three recognized primary pathogenic sites for LHON. G3460A of G11778A in ND4 region and 95% of T14484C locus of ND6 were caused by one of the three primary pathogenicity mutations. In China, the mutation rates of G11778A and G11778A were 92.91.4% and 5.775% respectively. The sporadic cases of the disease are high, the onset and the course of the disease are various, and it is easy to misdiagnose or miss diagnosis in clinic. Therefore, the mutation sites can be quickly and accurately screened by gene diagnosis in LHON patients. It has positive significance for the prevention and treatment of LHON. Purpose. To investigate the type and genetic characteristics of mitochondrial DNA mtDNA mutation in LHON patients in central China, and to screen new secondary sites in Chinese patients with LHON. Method. Routine ophthalmologic examination and brain MRI examination were performed on 189 suspected LHON patients (including 3 families). Then the methods of allele-specific PCR- MSP-PCRN, polymerase chain reaction-restriction fragment length polymorphism PCR-RFLP and polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) combined with DNA sequencing were used, respectively. The G11778Agna G3460A and T14484C3 primary loci were detected by mtDNA in 189 patients with suspected clinical symptoms suspected to be LHON. For the suspected patients lacking three primary mutation sites, the whole mitochondrial genome was sequenced to find other secondary mutation sites associated with the disease. Results. 1. Of the 189 suspected LHON patients, 86 were found to be one of the primary mutations G11778Agna G3460A and T14484C3. (2) among 86 cases of primary mutation, there were 6 cases of mutation at No. 3460 locus, 66 cases of mutation at site 711778, 14 cases of mutation at locus 7714 484, accounting for 16000 cases. 3. Of the 14 patients with 14484 locus mutation, 3 were simple 14484 primary mutation (22. 2%), 5 male (14484) with 14502 secondary mutation (33. 3%), 1 male (1 male) and 2 females (4 / 4) with 14470 mutation at 14484 locus. 33.3%, male 2 cases, female 1 case with 14484 locus with 14569 locus mutation, accounting for 11.1%. 4. By sequencing the whole mitochondrial genome, we found that some of the mutation sites A2706G, A1438G, T2115CN, G3538TN, C4262Afen, C4275G, C7028T, G8392Agnon A10485G and C10719T, were also found to be mutated in normal subjects. Conclusion. 1. G11778A mutation was the main mutation in LHON patients in central China, followed by G3460A mutation in T14484Cad. Among the mutants with T14484C locus, there were simple 14484 mutation, 14484 with 14502 mutation, 14484 with 14569 mutation and 14484 with 14470 mutation. Nd6 region was one of the hotspots in mitochondrial DNA mutation research. 3. By sequencing the whole mitochondrial genome, we found that some new secondary mutation sites may have synergistic effect on the pathogenicity of the primary loci.
【学位授予单位】：郑州大学
【学位级别】：硕士
【学位授予年份】：2012
【分类号】：R774.6

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