线粒体DNA11778突变所致Leber遗传性视神经病变外显率分析

目的 分析携带线粒体DNA（mitochondrialDNA,mtDNA)11778突变者视神经病变的外显率。方法 对经基因诊断确定为mtDNA11778突变的Leber遗传性视神经病变（Leber hereditary optic neuropathy,LHON)家系进行分析。确定mtDNA11778突变携带者及患者。结果 16个家系中mtDNA11778突变携带者130人,其中男65人,女65人,130人突变携带者中43人患病,外显率33.1%。男性患者34人,男性外显率52.3%,女性患者9人,女性外显率13.8%,男女患病比率3.8:1,患者中男性占79%。结论 携带纯合性mtDNA11778位点突变的中国人,LHON外显率近1/3。     

继发突变位点对Leber＇s遗传性视神经萎缩作用机制的研究

目的探讨继发突变位点在Leber’s遗传性视神经萎缩（Leber＇s hereditary optic neuropathy,LHON）疾病发生发展中的作用。方法对4个LHON家系患者及家系男性子代进行3个原发位点、24个继发位点及相邻片段检查。结果4家系均携带11778位点突变,所查患者无24个继发位点突变,但在这些位点的相邻片段上有5178、5108、3705、3721、13734等多个多态位点存在。结论线粒体多态位点具有家族遗传性,在LHON继发位点研究中应同时进行男性子代检查,以排查突变位点是否具有致病性。“修复基因”的存在可能对LHON疾病发展有影响。     

Leber遗传性视神经病变线粒体DNA突变的研究

目的 探讨Leber遗传性视神经病变患者的线粒体DNA突变类型及特点.方法 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12个家系中21位临床症状疑诊为LHON的患者及其19位无明显眼疾的母系亲属进行线粒体DNA检测.结果 40例受检者中35例发生11778位点突变,2位成员有3460位点突变,有1例发现有4258位点突变（A→G）.结论 11778是LHON患者常见的突变位点,3460突变少见,新发现的突变位点4258可能是新的继发突变或基因多态性.     

继发突变位点对Leber's遗传性视神经萎缩作用机制的研究

目的探讨继发突变位点在Leber’s遗传性视神经萎缩(Leber’s hereditary optic neuropathy,LHON)疾病发生发展中的作用。方法对4个LHON家系患者及家系男性子代进行3个原发位点、24个继发位点及相邻片段检查。结果4家系均携带11778位点突变,所查患者无24个继发位点突变,但在这些位点的相邻片段上有5178、5108、3705、3721、13734等多个多态位点存在。结论线粒体多态位点具有家族遗传性,在LHON继发位点研究中应同时进行男性子代检查,以排查突变位点是否具有致病性。"修复基因"的存在可能对LHON疾病发展有影响。     

中国人LHON患者mtDNA继发突变的筛查

目的分析中国人Leber遗传性视神经病变(Leber's hereditary optic neuropathy,LHON)线粒体DNA 4个继发突变位点与LHON发病的关系.方法分别用突变特异性引物聚合酶链反应,异源双链-单链构象多态性,限制性片段长度多态性和DNA测序方法,对137例LHON患者、60例不明原因球后视神经炎进行mtDNA3394C、9438A、13708A、4216C 4个继发位点的检测,并以100例正常人作对照.结果在4例LHON患者(包括3例11778突变、1例3460突变)、2例不明原因球后视神经炎患者及1例正常人中发现存在13708位点突变(G→A),引起ND5蛋白第458位中度保守丙氨酸变成苏氨酸(A458T).经χ2检验,无统计学意义.在1例正常人中检测到3394位点T→C突变,造成ND1蛋白第30位高度保守酪氨酸变成组氨酸(Y30H).137例LHON患者及60例不明原因球后视神经炎患者均未发现此位点突变.在137例LHON患者、60例不明原因球后视神经炎患者及100例正常人中未检测到9438及4216位点突变.结论我们的研究结果与日本、韩国研究结果相似,初步排除了在中国人kber遗传性视神经病变患者中13708A、3394C、9438A、4216C四种突变协同原发突变发病的可能性.     

Leber＇s遗传性视神经病线粒体DNA突变二例的检测

目的检测两例Leber＇s遗传性视神经病的突变位点.方法常规酚-氯仿法提取2名LHON患者基因组DNA,PCR扩增后对mtDNA11778进行检测.结果mtDNA11778位点处存在G→A突变.     

中国Leber遗传性视神经病变G11696A突变两个家系分析

目的对两个中国Leber遗传性视神经病变(Leber’shereditary optic neuropathy,LHON)家系的临床和分子遗传学特征进行分析。方法眼科临床检查发现在这两个家系中只有先证者1人出现视力障碍,发病年龄分别为10岁和17岁。对这两个家系先证者使用24对有部分重叠的引物进行线粒体DNA(mitochondrial DNA,mtDNA)全序列扩增分析。结果没有发现mtDNAG11778A、G3460A和T14484C3个常见的突变位点,而发现了与LHON相关的ND4G11196A同质性突变位点的存在,在167名正常对照只发现1例G11696A突变。结论线粒体DNA全序列分析发现两个家系呈现独特的mtDNA多态性,都属于东亚单体型D4。不完全外显率和正常对照频率(1/167)表明G11696A突变本身不足以导致LHON的发生,说明其它因素在这两个LHON家系的表型表达中也起一定的作用。在这些家系mtDNA中缺乏影响重要功能突变位点的存在,排除了线粒体背景对LHON临床表型的影响。因此,核修饰基因、环境因素可能对两个中国G11696A突变家系的外显率和发病严重程度起促进作用。     

线粒体tRNAThr A15951G可能是与Leber遗传性视神经病变相关的基因突变

目的 进一步分析中国汉族Leber遗传性视神经病变(Leber's hereditary optic neuropathy,LHON)家系的临床和分子遗传学特征,阐明LHON的分子致病机制.方法 对2例具有典型LHON临床特征的先证者和家系其他成员进行眼科学及其临床检查.对这2个家系先证者使用24对有部分重叠的引物进行线粒体DNA(mitochondrial DNA,mtDNA)全序列扩增分析.结果 检查发现这些家系成员中视力损害的外显率分别为5.3％(1/19)、18.2％(4/22).经mtDNA测序分析,并没有发现mtDNA G11778A、G3460A和T14484C 3个常见的突变,在tRNAThr上发现了A15951G同质性突变位点.线粒体DNA全序列分析显示2个家系呈现mtDNA多态性,都属于东亚单倍型D4b1.A15951G突变位于线粒体tRNAThr高度保守区(通用位点为71位),可能导致tRNA空间结构和稳定性发生改变,线粒体蛋白合成功能受损,最终发生视力损害.结论 线粒体tRNAThr A15951G可能是与Leber遗传性视神经病变相关的致病性线粒体基因突变.     

中国人Leber 遗传性视神经病变的原发突变及临床特征

目的 分析中国人Leber遗传性视神经病变(Leber’s hereditary optic neuropathy,LHON)线粒体DNA3个原发致病基因突变遗传及其临床特征。方法 分别用突变特异性引物聚合酶链反应,异源双链-单链构象多态性,限制性片段长度多态性和DNA测序方法,对110个家系的156例LHON患者进行11778A、3460A、14484C 3个原发位点检测,并收集患者病史及其临床资料,进行统计学分析。结果 110例LHON先证者中,11778位点突变者100例,占90．9％;3460位点突变者2例,占1．8％;14484位点突变者8例,占7,3％。不同突变位点的LHON患者发病时视力分布：125人(250眼)11778位点突变患眼中发病时视力≤0．01(占17．6％),视力介于0.01至0．1之间(占52．1％),视力≥0．1(占30．3％);28人(56眼)14484位点突变患眼中无患眼视力低于0．01视力介于001至0．1之间(占12．7％),视力≥0．1(占87．3％);3人(6眼)3460位点突变患眼视力均介于0．03至0．08之间。视力恢复情况：250只11778位点突变的患眼中,6．97％的眼视力有所恢复,平均最终视力0．03(指数～0．07);56只14484位点突变的患眼中,50％的眼视力有所恢复,占50％,平均最终视力0．8(0．3～1．2)。结论 中国人LHON患者mtDNA 3个原发致病突变中,以11778A位点突变为主、14484C位点突变较少、3460A罕见。LHON的临床表现与致病突变位点有关,14484C突变患者的发病视力及视力恢复情况明显好于11778A患者。     

线粒体单倍型对Leber病的影响

在Leber遗传性视神经病变(Leber's hereditary optic neuropathy,LHON)家系中由母系传递这种视觉功能障碍,提示线粒体基因组(mitochondrial DNA,mtDNA)突变为该疾病发生的主要分子基础.在不同种族人群的LHON家系中,有50%以上是由于mtDNA编码呼吸链复合体I上ND1 G4360A,ND4 G11778A和ND6 T14484C突变引起的.这3个突变位点因为致病率高,被称为原发性突变.但是携带这些位点突变的母系成员并不是都会出现LHON症状,而且在同一个家系内或不同家系间携带相同mtDNA突变的患者在发病年龄、视力损伤程度和发病过程也都不完全一样.这提示可能这些LHON相关的原发性突变本身不足以导致临床表现.IMON的男性多发、不完全外显和不同的基因表现度表明还有其他因素在疾病的发生发展过程起到修饰作用,这些因素包括:个人因素、环境因素、核修饰基因和mtDNA单倍型.特别是mtDNA单倍型,在对携带3个LHON相关原发性突变的家系中母系成员的发病起到协同作用.     

Phylogenetic analysis of Leber's hereditary optic neuropathy mitochondrial DNA's indicates multiple independent occurrences of the common mutations

The mitochondrial DNAs (mtDNA) from 17 Caucasian 11778-positive and 30 Caucasian 11778-negative Leber's hereditary optic neuropathy (LHON) patients were PCR-amplified and subjected to high resolution restriction endonuclease analysis. Concurrently, all patient mtDNAs were screened for the common primary LHON mtDNA mutations at nucleotide pairs (nps) 3460, 11778, and 14484, the ambiguous intermediate-risk LHON mtDNA mutations at nps 5244 and 15257, and the secondary LHON mtDNA mutations at nps 3394, 4216, 4917, 7444, 13708, and 15812. Phylogenetic analysis was performed using mtDNA haplotype data from the 47 LHON patients and 175 non-LHON Caucasian controls. The superimposition of the LHON mutation screening results upon the Caucasian mtDNA phylogeny revealed (1) 35 different LHON haplotypes, (2) that all three common primary mutations have occurred multiple times in Caucasians, (3) that while recurrent mutation is common for the primary mutations, secondary mutations tend to be lineage-specific, (4) that the np 15257 mutation was confined to a single mtDNA lineage but may be etiologically important in some LHON cases since it was found in a LHON pedigree which lacked a common primary mutation; complete sequence analysis of the proband mtDNA revealed only a single other candidate missense mutation (at np 10663 of the ND4L gene) of uncertain pathological significance; and (5) that the np 14484 mutation may be less pathogenic than either the np 3460 or np 11778 mutations, as this mutation most commonly occurred on a single mtDNA lineage and almost always in association with secondary LHON mutations. A phylogenetic ageneous disease has thus provided key genetic data bearing on the relative pathogenicity of the LHON-associated mtDNA mutations. © 1995 Wiley-Liss, Inc.     

Leber''s hereditary optic neuropathy: correlations between mitochondrial genotype and visual outcome.

Leber's hereditary optic neuropathy (LHON) is a maternally inherited disease associated with mitochondrial DNA (mtDNA) mutations. We describe the distribution of seven different mtDNA mutations and the clinical findings in 334 LHON patients belonging to 29 families. Mutations described only in LHON at nucleotide positions 11778, 3460, and 14484 were found in 15, two, and nine families respectively. In three families none of these mutations was found. Mutations described in LHON but also in controls at nucleotide positions 15257, 13708, 4917, and 4216 were found in one, 10, three and 12 families respectively. Combinations of mtDNA mutations were found in most families. The patient population mainly consisted of 79.2% to 89.5% males except for one family with only 10 of 17 patients being males (58.9%, p approximately 0.036). In 11 families only the 11778 mutation was found; in this group (WX) the affected males had a mean age of onset of 29.2 years and a mean visual outcome of 0.113. In seven families the 14484, 13708, and 4216 mutations were found; in this group (MA) the affected males had a mean age of onset of 22.0 years and a mean visual outcome of 0.442. In two families no mutation was found at all; in this group (YX) the affected males had a mean age of onset of 18.9 years and a mean visual outcome of 0.167. The mean age of onset in the WX group is significantly higher than in the MA group (p < or = 0.001) and in the YX group (p approximately 0.01). The mean visual outcome in the MA group is significantly better than in the WX group (p </= 0.001) and the YX group (p = 0.05). No significant clinical differences were found between families exhibiting only the 11778 mutation and those with additional mutations at np 13708, 4917, or 4216, suggesting that these mutations are of little phenotypic importance. Other mutations were present in relatively small numbers of patients. These results show that the clinical severity is dependent on the mitochondrial genotype.     

A simple oligonucleotide biochip capable of rapidly detecting known mitochondrial DNA mutations in Chinese patients with Leber's hereditary optic neuropathy (LHON)

Leber's hereditary optic neuropathy (LHON) is a maternally transmitted disease. Clinically, no efficient assay protocols have been available. In this study, we aimed to develop an oligonucleotide biochip specialized for detection of known base substitution mutations in mitochondrial DNA causing LHON and to investigate frequencies of LHON relevant variants in Anhui region of China. Thirty-two pairs of oligonucleotide probes matched with the mutations potentially linked to LHON were covalently immobilized. Cy5-lablled targets were amplified from blood DNA samples by a multiplex PCR method. Two kinds of primary mutations 11778 G > A and 14484 T > C from six confirmed LHON patients were interrogated to validate this biochip format. Further, fourteen Chinese LHON pedigrees and twenty-five unrelated healthy individuals were investigated by the LHON biochip, direct sequencing and pyrosequencing, respectively. The biochip was found to be able efficiently to discriminate homoplasmic and heteroplasmic mtDNA mutations in LHON. Biochip analysis revealed that twelve of eighteen LHON symptomatic cases from the 14 Chinese pedigree harbored the mutations either 11778G > A, 14484T > C or 3460G A, respectively, accounting for 66.7%. The mutation 11778G > A in these patients was homoplasmic and prevalent (55.5%, 10 of 18 cases). The mutations 3460G > A and 3394T > C were found to co-exist in one LHON case. The mutation 13708G > A appeared in one LHON pedigree. Smaller amount of sampling and reaction volume, easier target preparation, fast and high-throughput were the main advantages of the biochip over direct DNA sequencing and pyrosequencing. Our findings suggested that primary mutations of 11778G > A, 14484T > C or 3460G > A are main variants of mtDNA gene leading to LHON in China. The biochip would easily be implemented in clinical diagnosis.     

山西地区线粒体DNA11778突变所致Leber遗传性视神经病变外显率分析

目的　分析山西地区线粒体 DNA11778位点突变者外显率。方法　应用等位基因特异性PCR检测视神经病变者线粒体DNA11778位点 ,对突变者及其母系成员进行分析。结果　在 30个家系中 17个家系仅先证者患病 ,另 13个家系除先证者外母系亲属有 72人携带该位点突变 ,其中 4 0人出现临床症状。结论　山西地区线粒体 DNA11778位点突变者外显率达 5 5 .6 %。     

Clinical, genetic, and biochemical characterization of a Leber hereditary optic neuropathy family containing both the 11778 and 14484 primary mutations.

Four mitochondrial DNA (mtDNA) mutations at nps 3460, 11778, 14484, and 14459 account for roughly 90% of cases of Leber hereditary optic neuropathy (LHON) and are designated as "primary" LHON mutations since they act as major predisposition factors for LHON. Although each primary mutation can arise independently on different mtDNA backgrounds during human evolution, they characteristically do not co-occur in LHON patients. We report here a family with the simultaneous occurrence of the 11778A and 14484C mutations. Neuro-ophthalmological examination of the proband, a nine-year-old Caucasian female, revealed the bilateral optic atrophy, central scotomas, and reduced visual acuity typical of LHON. Her mother had normal appearing optic discs and is today visually asymptomatic. Analysis of the proband blood mtDNA revealed that she harbored both the 11778A (heteroplasmic, 94% mutant) and the 14484C (homoplasmic mutant) mutation. This genotype was maintained in proband lymphoblasts and transmitochondrial cybrids. The mother also had both mutations, with the 14484C mutation homoplasmic in all cell types examined. However, only 31% of her blood mtDNAs carried the 11778 mutation, which segregated to essentially 100% wild-type in lymphoblast and cybrid mtDNA. Complex I-linked respiration and specific enzyme activity were consistently lowest in proband lymphoblast and cybrid mitochondria compared to those from the mother, 11778A patients, 14484C patients, or controls, thus demonstrating both a deleterious synergistic interaction between the 11778A and 14484C mutations and the magnitude of 11778A-associated complex I dysfunction. Remarkably, spontaneous vision recovery occurred in the proband, highlighting the complexities encountered when associating mtDNA genotype and complex I function with LHON expression.