A family with Leber's hereditary optic neuropathy with mitochondrial 11778/ND4 and 4216/ND1 mutations

Leber's hereditary optic neuropathy (LHON) is caused by a point mutation in the mitochondrial deoxynucleic acid (mtDNA) and accounts for 30% of bilateral optic atrophy of unknown etiology. The authors found a Korean family with mtDNA mutations in the nucleotide positions (np) 11778 and np 4216. This is the first report confirming a secondary mtDNA np 4216 mutation in Koreans, as well as the first report of a Korean family harboring both primary and the secondary mutations that the authors are aware of.     

单核苷酸多态性核酸试纸快速检测线粒体DNAG11778A位点突变

目的建立一种以单核苷酸多态性核酸试纸快速检测Leber’s遗传性视神经病变（Leber’s hereditary optic neuropathy，LHON）线粒体DNA中G11778A位点突变的新方法。方法与结果32例阳性（突变）和5例阴性（正常）临床血样标本经DNA提取、PCR扩增和单碱基延伸反应处理后，采用单核苷酸多态性核酸试纸每方法对标本的线粒体DNAG11779A位点进行了检测，其符合率为100％。本研究还使用该方法对10例口腔黏膜上皮细胞样本进行了随机检测，结果表明单核苷酸多态性核酸试纸条检测结果和DNA测序结果完全一致。结论该方法简便、快速、准确、经济，适合于各级医院尤其是中小医院LHON的G11778A位点突变的快速筛查，它不仅可以为LHON的临床诊断和鉴别诊断提供有力的依据，而且具有重要的临床推广价值。     

Phylogenetic assessment of the mitochondrial DNA displacement loop haplotype in Japanese patients with Leber's hereditary optic neuropathy harboring the mitochondrial DNA G11778A mutation

To investigate the anthropological background and the association of mitochondrial DNA (mtDNA) haplotype with the disease phenotype, the nucleotide sequence in the hypervariable segment of the displacement loop (D-loop) region of mtDNA was determined in Japanese patients with Leber's hereditary optic neuropathy (LHON) harboring the G11778A mutation. Genetic polymorphism of mtDNA was examined in 36 unrelated Japanese LHON patients who presented with bilateral optic nerve disease and had the mtDNA G11778A mutation. DNA was extracted from the peripheral blood after having obtained informed consent. The nucleotide sequence of the D-loop region (np 16,002-16,490) was directly determined. The intergenic deletion of the COII/tRNA(Lys) gene of mtDNA was also examined. From the data set of nucleotide alignments, the phylogeny of the mtDNA sequence and phenotypic diversity within the examined population were evaluated. One-base polymorphism was present at 37 different sites. The estimated value of nucleotide diversity was 0.69%. D-loop sequences were classified into 13 monophyletic clusters (CA to CM). There was not any definite ancestral haplotype of the D-loop sequence in the examined LHON population. Thus, the mutational event of G11778A appears to be independent of the evolutionary course in the D-loop haplotype. Patients with a CD plus CH cluster had a significantly older age at onset (p = 0.006), and had a family history being significantly lower as compared with patients with other clusters (p = 0.05). The mtDNA D-loop haplotype characterized by the presence of T16362C or C16290T, lacking G16129A and G16390A, may be a risk for older age at onset and other unusual clinical features in Japanese LHON patients with the G11778A mutation.     

携带ND1基因G3635A突变的Leber遗传性视神经病变三家系线粒体基因突变位点检测及其分子遗传致病机制

目的 观察3个ND1基因G3635A突变Leber遗传性视神经病变(LHON)家系线粒体基因组中的突变位点,探讨其分子遗传致病机制。方法 3个家系共88名成员纳入本研究。母系成员53名,非母系成员35名。分别采用标准对数视力表、佳能眼底数码彩色照相、Humphrey视野计、俞自萍色觉图、德国罗兰电生理仪对所有成员行视力、眼底、视野、色觉及视觉诱发电位检查。其中,确诊为LHON 16例,未患LHON 72名。选择135名无血缘关系的中国温州地区正常健康者作为对照组。抽取所有受试者外周静脉血,提取全基因组DNA,检测ND1基因G3635A突变位点。采用扩增产物片段有重叠的24对引物,检测3个家系先证者线粒体单体型分型和基因组突变位点。结果 3个家系先证者及母系成员均发现ND1基因G3635A突变位点,非母系成员和对照组受试者均未发现ND1基因G3635A突变位点。先证者线粒体单体型分型分别为东亚单体型N9a3、D4、R11a。先证者线粒体全基因组检测发现,除ND1基因G3635A突变位点外,D-Loop区存在12个变异位点,RNA编码区存在6个变异位点,多肽编码区存在36个变异位点。结论 3个ND1基因G3635A突变家系先证者及母系成员均存在G3635A突变位点;G3635A突变位点是3个家系的分子遗传致病基础。     

Leber遗传性视神经病变患者G11778A位点突变与临床预后的关系

背景 Leber遗传性视神经病变是一种典型的母系遗传性疾病,已经发现线粒体的多个突变可以导致该病的发生. 目的 报道2个携带线粒体G11778A位点突变的Leber遗传性视神经病变(LHON)家系及其临床预后. 方法 对在郑州大学第一附属医院眼科收集到的2个LHON家系40人进行家系分析和基因检测.2个家系成员中包括母系成员28人,其中LHON病患者10例,作为研究组,母系男性成员的后代及配偶2例作为对照组.抽取受试者外周血2 ml,常规酚-氯仿-异戊醇法抽提外周血基因组DNA,应用逆转录聚合酶链反应(RT-PCR)扩增目的基因,对受试者基因进行测序,对3个常见突变位点G3460A、G11778A、T14484C进行检测和筛查. 结果 本研究中的2个家系所有母系成员(包括患者)均携带G11778A位点突变,家系内对照者未携带该突变位点.所有的家系成员未携带G3460A和T14484C位点的原发突变.这2个家系中的LHON患者视力均等于或低于0.1,未见有视力自行恢复者. 结论 本研究2个家系患者均携带G11778A点突变,视力预后较差.     

G11778A突变型Leber遗传性视神经病变患者血清总超氧化物歧化酶活力和丙二醛含量的研究

目的 检测G11778A突变型Leber遗传性视神经病变(LHON)患者血清总超氧化物歧化酶(SOD)活力和丙二醛(MDA)含量并了解LHON患者体内氧化与抗氧化状态.方法 病例对照研究.纳入经眼科检查和线粒体基因测序确诊的G11778A基因突变型LHON患者19例,G11778A基因突变携带者(携带者)12例,正常对照者30例,分别应用黄嘌呤氧化酶法和硫代巴比妥酸法检测受试者血清总SOD活力和MDA含量.应用SPSS 12.0统计学软件包.采用单因素三水平设计定量资料方差分析,分别计算LHON患者、携带者及正常对照者血清总SOD活力和MDA含量的均数及标准差,比较3组受试者间各检测指标的均数差异;若有差异则进行多个均数两两比较的q检验.结果 LHON患者、携带者和正常对照者的血清总SOD活力分别为(22.01±7.21)×103 U/L、(43.44±14.70)×103U/L及(42.70 ±12.51)×103U/L,差异有统计学意义(F=20.875,P＜0.05).LHON患者血清总SOD活力较携带者和正常对照者均明显下降(q值分别为7.085,8.351;均P＜0.05),携带者与正常对照者的血清总SOD活力差异无统计学意义(q=0.269,P＞0.05).LHON患者、携带者及正常对照者的血清MDA含量分别为(10.39±4.38)mmol/L、(7.08±2.51)mmol/L及(2.97±1.81)mmol/L,差异有统计学意义(F=20.109,P＜0.05).LHON患者和携带者血清MDA含量均明显高于正常对照者(q值分别为9.069,4.748;均P＜0.05),LHON患者的血清MDA含量也高于携带者(q=3.618,P＜0.05).结论 LHON患者体内抗氧化能力明显下降,机体氧化与抗氧化系统失衡与LHON患者的发病有关.     

Photoreceptor changes in Leber hereditary optic neuropathy with m.G11778A mutation

AIM: To evaluate the functional and structural changes of photoreceptors in patients and asymptomatic carriers with Leber hereditary optic neuropathy (LHON) using full-field electroretinography (FERG) and optical coherence tomography (OCT).METHODS: Individuals diagnosed with LHON at the Renmin Hospital of Wuhan University and their family members were included in this cross-sectional observational study. The FERG a-wave amplitude of affected patients and asymptomatic carriers was analyzed. The thickness of the outer nuclear layer (ONL), inner and outer segment (IS/OS) and total photoreceptors in the macular fovea and parafovea were measured.RESULTS: This study included 14 LHON patients (mean age: 20.00±9.37y), 12 asymptomatic carriers (mean age: 39.83±6.48y), and 14 normal subjects (mean age: 24.20±1.52y). The FERG results showed that the dark-adapted 3.0 electroretinography and light-adapted 3.0 electroretinography a-wave amplitudes of patients and carriers were significantly decreased (P<0.001). The ONL and photoreceptors layers were slightly thicker in patients than in normal subjects (P<0.05), whereas they were thinner in carriers (P<0.05). There were no differences in IS/OS thickness among the groups (P>0.05).CONCLUSION: Photoreceptors function is significantly impaired in LHON-affected patients and asymptomatic carriers. Meanwhile, photoreceptors morphology is slightly altered, mainly manifesting as a change in ONL thickness.     

G11778A位点突变Leber遗传性视神经病变的视野特点和变化趋势

目的观察并分析G11778A位点突变Leber遗传性视神经病变(LHON)患眼视野特点和变化趋势。方法回顾性临床研究。2008年5月至2018年2月在北京中医药大学东方医院眼科经线粒体DNA检测确诊的G11778A位点突变LHON患者22例44只眼纳入研究。患眼均行最佳矫正视力(BCVA)、视野、光相干断层扫描(OCT)检查。BCVA检查采用国际标准视力表进行,统计时换算为最小分辨角对数(logMAR)视力。采用OCT仪测量以视盘为中心1.73 mm外200μm×200μm环形区域的视网膜神经纤维层(RNFL)厚度。采用Octopus 101型视野计于患者病程2、4、8、12、18、24、30个月时间点前后1个月内分别完成至少7次以上视野检查。因初诊时患者BCVA和配合度的不同,其中27只眼采用G2程序进行视野检查(G2程序组),以视野平均缺损(MD)为主要结局指标;17只眼采用LVC程序进行视野检查(LVC程序组),以视野平均光敏感度(MS)为主要结局指标。两组患者性别构成比(χ²=1.896)、年龄(t=0.337)比较,差异无统计学意义(P=0.169、0.708);logMAR BCVA比较,差异有统计学意义(t=4.994,P=0.000)。根据患者发病年龄是否>14岁,再将两组患者分为年龄≤14岁组、>14岁组。组间比较采用独立样本t检验,组内比较采用配对t检验,多组间比较采用单因素方差分析;计数资料比较采用χ²检验。结果G2程序≤14岁组患眼随病程延长视野MD值逐渐降低;与病程2个月比较,病程18个月后视野MD值明显降低,差异有统计学意义(t=3.813、4.590、5.033,P=0.002、0.001、0.000)。G2程序>14岁组患眼不同病程视野MD值比较,差异无统计学意义(P>0.05)。LVC程序≤14岁组、>14岁组患眼不同病程视野MD、MS值比较,差异均无统计学意义(P>0.05)。患眼早期视野缺损主要表现为中心暗点,晚期则为弥漫性视野缺损。早期、晚期视野缺损类型眼数比较,G2程序组差异有统计学意义(χ²=17.414,P=0.015);LVC程序组差异无统计学意义(χ²=4.541,P=0.474)。G2程序组患眼病程8个月内视野MD值基本维持稳定;与病程2个月视野MD值比较,病程18个月后视野明显改善,MD值下降,差异有统计学意义(t=2.100、3.217、3.566,P=0.046、0.003、0.001)。LVC程序组患眼随访期间视野MS无明显改善(P>0.05)。G2程序组患眼,与病程2个月BCVA比较,病程12个月后BCVA明显提高,差异有统计学意义(t=3.039、3.678、4.264、5.078,P=0.008、0.002、0.001、0.000)。G2程序组患眼不同病程BCVA均优于LVC程序组,差异有统计学意义(P≤0.05)。G2程序组(t=8.400、9.330、10.989、11.967、12.211、12.803)、LVC程序组(t=10.668、13.036、13.833、18.922、20.387、20.851)患眼随病程延长RNFL厚度持续降低,差异有统计学意义(P值均为0.000)。G2程序组患眼病程4、8、18、24、30个月RNFL厚度均高于LVC程序组,差异有统计学意义(t=2.471、2.269、2.474、2.509、2.782,P=0.018、0.028、0.017、0.016、0.008)。结论G11778A位点突变LHON患眼视野缺损早期主要表现为中心暗点,晚期主要表现为弥漫性缺损和中心暗点。G2程序组患眼随访期间视野明显改善,BCVA显著提高;G2程序组中年龄≤14岁者视野改善优于年龄>14岁者。LVC程序组患眼随访期间视野MS无明显改善。     

G11778A位点突变的9例Leber遗传性视神经病变患者的临床特征

目的：探讨经线粒体DNA分析(mtDNA)确诊为G11778A位点突变阳性的9例Leber遗传性视神经病变( LHON )患者的临床特征。
　　方法：收集2012-12/2015-12就诊于深圳市眼科医院门诊行mtDNA检测均为G11778 A突变的9例LHON患者的临床资料,随访并总结其临床特征。
　　结果：所选9例患者中,有母系遗传者6例(67%),散发病例3例(33%)。就诊年龄9~43(平均22.00±9.42)岁。其中双眼同时发病5例(56%);双眼先后发病4例(44%)。发病者男女比例为2：1。末次随访时,数指2眼(11%);0.01~0.1者12眼(67%);0.12~0.4者2眼(11%);≥0.4者2眼(11%)。所有患者均表现为视盘色苍白、边界清楚。视野检查表现为中心暗点或者旁中心暗点10眼,表现为弥漫性视野损害8眼。
　　结论：此次收集的9例G11778 A位点突变的LHON患者中,双眼同时发病较1a内单眼先后发病的患者的情况更为多见。病程末期视力稳定病例较视力持续损害病例多。少数患者在1a内患眼有视力提高的情况。视野缺损表现多见中心暗点或者旁中心暗点,病程末期可见视野弥漫性缺损。继发眼的视野损害与先发作眼视野表现类似。     

High frequency of mitochondrial ND4 gene mutation in Japanese pedigrees with Leber hereditary optic neuropathy.

The association of the ND4 gene mutation (mutation) at nucleotide position 11778 of mitochondrial DNA (mtDNA) was investigated in 14 definitive Japanese pedigrees with Leber hereditary optic neuropathy (LHON). The mutation was detected by SfaNI and MaeIII restriction fragment length polymorphisms of mtDNA amplified by polymerase chain reaction. All 14 LHON pedigrees exhibited the mutation, whereas 10 controls did not. The association of this mutation with LHON was revealed to be significantly higher in Japanese (91.7%) than in 27 reported Caucasian (51.9%) LHON pedigrees, implying genetic heterogeneity. In the tested 14 pedigrees, 28 cases with the mutation comprised 19 affected (17 male and 2 female) and 9 asymptomatic (all female except for one) individuals. Such a predominance of males in the incidence of LHON suggested probable participation of additional pathogenetic factor(s) in the development of optic atrophy in LHON patients.     

Exclusive homoplasmic 11778 mutation in mitochondrial DNA of Chinese patients with Leber's hereditary optic neuropathy.

PURPOSE: To investigate the degree of heteroplasmy of the 11778 mtDNA mutation in Chinese patients with Leber's hereditary optic neuropathy (LHON). METHODS: Seventeen Chinese Leber's pedigrees, including 24 patients, 17 unaffected maternal lineages, 4 internal controls, and 6 unrelated controls, were screened for the 11778 mtDNA mutation. This was carried out by analysis of the restriction fragment length polymorphism, single-strand conformation polymorphism, and DNA sequencing. RESULTS: All patients and unaffected maternal lineages, regardless of their symptoms, had homoplastic 11778 mtDNA mutation, which was revealed by restriction fragment length polymorphism analysis and single-strand conformation polymorphism analysis. CONCLUSION: Exclusive homoplasmy of the 11778 mtDNA mutation in Chinese LHON patients was found in this study. Homoplasmy of the 11778 mtDNA mutation cannot account for the variation in the clinical phenotype of Chinese Leber's patients.     

Increase of mitochondrial DNA in blood cells of patients with Leber's hereditary optic neuropathy with 11778 mutation

AIMS: To investigate the change of mitochondrial DNA (mtDNA) content in Leber's hereditary optic neuropathy (LHON) with 11778 mutation. METHODS: Mitochondrial DNA content in 27 LHON patients with 11778 mutation, 26 asymptomatic maternal relatives, and 23 normal controls was measured using a competitive polymerase chain reaction (PCR) method. RESULTS: The mean relative content of mtDNA (with respect to the beta actin gene) in LHON patients, asymptomatic maternal relatives, and normal controls was 245.5 (162.3), 238.2 (118.4), and 156.5 (61.6), respectively. There was a statistically significant difference between patients and controls and between relatives and controls. However, no statistically significant difference between patients and unaffected relatives was found. There was no statistically significant difference in the relative content of mtDNA between all males and females carrying 11778 mtDNA mutation CONCLUSION: The results suggest that the increase in mtDNA content in LHON patients with 11778 mtDNA mutation may be due to a compensatory effect for respiratory chain defects of mitochondria. However, the increase of mtDNA content is the result rather than the cause of defective mtDNA. It still cannot explain the pathogenesis of LHON.     

荧光MGB探针在Leber遗传性视神经病变mtDNA G11778A基因突变检测中的应用

目的 建立一套快速、准确、简便筛查Leber遗传性视神经病变（LHON）mtDNAG11778A基因突变的新方法,并初步判断其异质性个体中野生和突变比例。方法 采用荧光MGB探针实时聚合酶链反应（PCR）技术,在同一个反应体系中引入野生和突变型两种探针,应用多荧光通道PCR仪分别检测LHON家系中20例患者血样和17例正常人血样,将检测结果与核酸序列测定结果比较。结果 正常人血样检测结果：荧光PCR技术检测VIC通道均为阳性,FAM通道均为阴性,判断为LHON mtDNA野生型,与测序结果完全吻合;临床LHON患者及家系成员测序结果：LHON mtDNA变异型患者12例,荧光PCR技术检测均为LHON mtDNA变异阳性,其中为LHON mtDNA变异株和野生株混合的5例,混合型中变异株与野生株Ct值均大于25％;测序结果显示LHONmtDNA野生型8例,荧光PCR技术检测LHONmtDNA野生型为5例,LHONmtDNA变异株和野生株混合型3例,其中变异株与野生株ct值均小于25％;荧光定量PCR技术检测LHON mtDNAG11778A基因突变耗时仅为80min,远短于测序时间。结论 荧光MGB探针实时PCR技术能简便、快速、准确地检测LHON mtDNAG11778A基因突变,判断个体异质性中野生和突变比例,对进一步探讨LHON患者是否存在mtDNA基因突变阈值有重要价值。（中华眼科杂志,2006,42：728—732）     

全血样等位基因特异性聚合酶链反应法筛查Leber遗传性视神经病变线粒体DNA G11778A位点突变

目的建立全血样等位基因特异性聚合酶链反应(PCR)法快速筛查Leber遗传性视神经病变(LHON)患者线粒体DNA G11778A位点突变。方法采用直接以全血样为模板的等位基因特异性PCR法检测14例阳性对照和10例阴性对照血样。同时对22例血样进行双盲检测。 结果24份对照血样检测结果表明该方法的准确率为100%,而且以全血样为模板的PCR特异性优于以纯化DNA为模板的。双盲检测22例血样发现7例阳性结果和15例阴性结果,与预期结果相一致。结论该方法简便、快速、准确、经济,非常适合临床基因诊断线粒体DNA G11778A位点突变的LHON患者,具有重要的临床推广应用价值。     

Confirmation of the 14568 mutation in the mitochondrial ND6 gene as causative in Leber's hereditary optic neuropathy

Leber's hereditary optic neuropathy (LHON) is a maternally inherited disorder characterized by a rapid bilateral loss of central vision. The majority of patients have one of three mutations in the mitochondrial DNA. In order to identify the genetic cause of the disease in a family with two affected individuals without any of the three primary LHON mutations, we have sequenced the complete mitochondrial genome. Sequence analysis revealed a point mutation at position 14568 in the mitochondrial ND6 gene that changes a conserved methionine residue to isoleucine. This mutation has been previously suggested to be of pathogenic significance and has not been detected in any controls. This case confirms the pathogenicity of this mutation. It is the seventh mutation in the ND6 gene leading to LHON. All seven identified mutations in the ND6 gene lie within the evolutionarily most conserved region of the ND6 gene in a hydrophobic pocket making it a hot spot for the disease. This clustering of mutations may help to understand the disease mechanism of LHON.     

Pigmentary retinopathy in patients with the MELAS mutation 3243A→G in mitochondrial DNA

BACKGROUND: Our objective was to determine the penetrance of retinal pigment epithelium (RPE) abnormalities and other ophthalmologic manifestations in patients with the 3243A-->G mutation in mitochondrial DNA. METHODS: Adult members in two generations were examined from a population-based cohort of 13 pedigrees with 3243A-->G. Twenty-six patients underwent a thorough ophthalmological examination. A chart review was carried out on an additional 44 patients. RESULTS: Paramacular RPE atrophy and areas of hyperpigmentation were found in 10 patients (38%; 95% confidence interval 20-59%). Electroretinography was normal in only one of the eight patients tested, whereas dark adaptation was abnormal in two. RPE abnormalities were associated with more severe clinical phenotypes and higher degrees of 3243A-->G mutation heteroplasmy in muscle. Ten patients had diabetes mellitus, nine of whom had also RPE abnormalities. This finding, however, reflected the severity of the phenotype, and diabetic retinopathy was confidently diagnosed in only two patients. External ophthalmoplegia was detected in occasional patients. CONCLUSION: RPE abnormalities were found in this population-based cohort at a frequency that was lower than that reported earlier. RPE abnormalities were associated with more severe phenotypes, suggesting that they are expressed in patients with syndromic features. RPE abnormalities and diabetes mellitus co-occurred frequently, but diabetic retinopathy was not common.     

The clinical characteristics of pedigrees of Leber's hereditary optic neuropathy with the 11778 mutation

In a study of the phenotypic characteristics of pedigrees of Leber's hereditary optic neuropathy positive for the mitochondrial DNA mutation at position 11778, 28 of 49 pedigrees were represented by singleton cases. Seven families, including six singleton pedigrees, had maternal family members with a mixture of mutant and normal mitochondrial DNA (heteroplasmy). Seventy-two affected individuals from 43 families showed a male predominance of 81.9% (59/72) and ages of onset of visual loss ranging from 8 to 60 years. The time interval between affected eyes averaged 1.8 months; the duration of progression of visual loss in each eye averaged 3.7 months. Visual acuity was 20/200 or worse in 107 of 109 (98.2%) eyes. Telangiectatic microangiopathy, disk pseudoedema, or vascular tortuosity, ophthalmoscopic features believed to be classic of Leber's hereditary optic neuropathy, were noted in 30 of 52 patients. Visual-evoked responses were typically absent or abnormal. Electrocardiograms, fluorescein angiograms, cerebrospinal fluid analyses, brain computed tomography, and magnetic resonance imaging were usually normal. There were no consistent neurologic or systemic illnesses associated with these Leber's pedigrees. In many cases, the diagnosis would not have been suspected because of the absence of a compatible family history, typical clinical profile, or ophthalmoscopic appearance. Genetic analysis showed the mitochondrial DNA mutation at position 11778, which established the diagnosis of Leber's hereditary optic neuropathy and has allowed for a broader view of the clinical features of this disease.