T14502C突变位点在Leber遗传性视神经病变发生发展中的作用

目的分析T14502C突变位点在Leber遗传性视神经病变(Lebers hereditary optic neuropathy,LHON)发生发展中的作用。方法对15例家系成员进行视力、眼压、裂隙灯、眼底、色觉及眼底荧光素血管造影等眼科检查;对以上成员进行高盐法线粒体DNA提取,针对目前公认的3个原发性突变位点G11778A、T14484C、G3460A进行PCR,扩增产物纯化后进行双向测序。结果 15例家系成员中,10例同时携带有G11778A和T14502C两个突变位点,其中的3例为LHON患者。平均发病年龄13岁,均为男性且均无视力恢复。结论与单独携带G11778A位点的中国家系相比,同时携带G11778A和T14502C位点可能导致家系成员LHON发病年龄偏低以及更加不良的视力预后。     

中国Leber遗传性视神经病变14484位点突变的家系分析

目的:了解我国Leber遗传性视神经病变(Leber’shereditaryopticneuropathy,LHON)线粒体DNA(mtDNA)14484位点突变患者的发病率和临床特征。方法:对来自117个家系的119例临床确诊或疑诊LHON的患者进行mtDNA检测。对3例证实为14484位点突变的家系做深入调查并收集相关病史及临床资料,抽取15例家属的血样进行mtDNA检测。结果:存在线粒体DNA突变的62例(62/119,52.1%)中,14484位点突变仅3例(4.8%)。该3例3个家系56例中,28例有眼部症状,外显率50%。发病经过和临床表现类似11778位点突变的LHON,但其中视力恢复者17例(60.7%)。15例家属的血样检测再次证实为14484位点突变。结论:我国LHON患者中14484位点突变者少见,其临床表现与11778位点突变者相似,惟视力恢复率高。     

Leber遗传性视神经病变11696位点突变的家系分析

目的了解我国Leber遗传性视神经病变（Leber’s Hereditary Optic Neuropathy，LHON）线粒体DNA（mtDNA）11696位点突变病人的临床特征。方法对来自51个家系的54例临床确诊或疑诊LHON的病人进行mtDNA检测，进行全基因排序分析。结果对3例证实为11696位点突变的家系做深入调查并收集相关病史及临床资料。3位先证者均是家系中唯一发病者，发病经过和临床表现类似11778位点突变的LHON。在随防中，有一例先证者视力恢复至1．0，其余2例视力无变化。结论LHON病人中11696位点突变者少见，其临床表现与11778位点突变者相似，预后差异大。     

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.     

Leber''''s遗传性视神经病变一个双生子家系的研究

目的探讨Leber＇s遗传性视神经病变（Leber＇s hereditary optic muropathy，LHON）一个双生子家系的临床和分子遗传学特征。方法对LHON一个家系进行家系调查，分析其遗传特征和发病特点，并对家系成员（发病者、未发病者及对照者）进行眼科临床检查（包括视力、视野、眼底及电生理检查）和线粒体基因三个原发性突变位点的检测，即自全血提取线粒体DNA（mtDNA），应用聚合酶链反应技术，分别扩增mtDNA上相应片段检测G3460A、G11778A和T14484C位点突变。最后应用分子遗传学技术对该家系中的一对双生子（其中一人为先证者，另一个未患病）进行DNA多态性的比较分析以鉴定其卵性。结果该家系显示为典型的母系遗传，先证者的临床表现为典型的LHON患者表现；母系亲属mtDNA的G11778A位点突变阳性，G3460A和T14484C位点突变阴性，而对照者三个位点检测结果均为阴性，双生子卵性鉴定结果为异卵双生。结论该家系为典型的LHON家系，mtDNA上G11778A位点突变可导致LHON的发生，但并不是所有G11778A位点突变者均发生LHON。     

Leber遗传性视神经病变线粒体ND6 T14502C突变的三个汉族家系

目的对3个中国汉族Leber 遗传性视神经病变（LHON）家系的临床和分子遗传学特征进行分析。方法 实验研究。收集3个临床诊断为LHON的中国汉族家系。对3个家系的先证者及母系成员进行眼科相关检查,并用24对部分重叠的引物进行全序列扩增。结果 发现先证者视力轻度损害,家系外显率低,分别为：11.1%、10.0%、4.0%。3个家系的先证者都未携带ND1 G3460A、ND4 G11778A、ND6 T14484C这3个常见原发突变,发现先证者的ND6 T14502C（I58V）同质性突变,多态性位点属于东亚线粒体单体型M10a。mtDNA ND6 14502位点T-C碱基的改变使ND6亚基第58位进化高度保守的异亮氨酸变为缬氨酸。结论 线粒体ND6 T14502C突变可能是LHON相关的线粒体突变位点之一。     

中国邢台地区Leber遗传性视神经病变分子流行病学调查研究

目的：：初步估测 Leber 遗传性视神经病变( Leber’s hereditary optic neuropathy,LHON)在中国邢台地区的发病率及分子流行病学特点。方法：对2001-12/2014-12就诊于河北省眼科医院(原邢台市眼科医院)的可疑 LHON 患者进行 mtDNA ( mitochondrial DNA)检测,筛选出中国华北南部邢台籍的LHON患者,对这些LHON家系进行详细的随访、家系调查、视力、眼底、色觉、视野等相关临床检查,确诊出这些家系的患病人群,以2010年国家第六次人口普查时邢台地区常住人口为基数,对入组的LHON家系进行统计学分析,粗略地估算出邢台地区Leber遗传性视神经病变的发病率与分子遗传学特点。结果：2001-12/2014-12期间调查了33个LHON家系的4代母系成员463例,确诊中国华北南部邢台籍Leber遗传性视神经病变患者72例,男65例,女7例。其中T3866 C 位点突变1例, G11778 A 位点突变60例, T14484C位点突变8例,G11696A+G11778A位点同时突变2例,G3460A突变1例。以2010年国家第六次人口普查时邢台地区0~64岁常住人口数6592466作为基数,计算出中国邢台地区Leber遗传性视神经病变患病率为1.092/10万(95%CI：0.964/10万~1.22/10万),其中以G11778A位点突变最为常见,G11778A位点的发病率为0.91/10万(95%CI：0.79/10万~1.03/10万)。结论：Leber遗传性视神经病变在中国邢台地区的发病率较高,其患病率的下限约为1.092/10万,其中ND4为突变热点区域,以G11778 A位点突变最为常见,男性患者较女性患者明显多。     

Leber 遗传性视神经病变一家系线粒体DNA突变检测及临床分析

Leber遗传性视神经病变（LHON）系一种主要累及视盘黄斑束纤维，导致视神经退行性病变的遗传性疾病，临床多表现为双眼急性或亚急性中心视力减退及进行性视神经萎缩。目前认为该病与线粒体DNA突变密切相关。我们对一临床诊断为LHON的家系的资料进行分析，并应用聚合酶链反应（PCR）和限制性核酸内切酶酶谱分析技术，对部分家系成员进行mtDNA核苷酸位点（3460、11778、14484）的突变检测。现将结果报道如下。     

Leber病一家系线粒体DNA突变检测与临床观察

目的 探讨Leber病一家系的临床和分子遗传学特征.方法 对Leber病一家系49个成员进行家系调查,分析其遗传特征和临床发病特点,并对家系现存成员进行眼科临床检查(视力、视野、眼底、色觉检查及视觉诱发电位检查),全血滤纸法提取线粒体DNA(mtDNA),应用聚合酶链反应(PCR)技术,分别扩增mtDNA上相应片段检测G3460A、G11778A和T14484C位点突变.结果 该家系显示为典型的母系遗传,共18例36眼患病,男11例22眼,女7例14眼.母系亲属mtDNA的G11778A位点突变阳性,3460和14484位点突变阴性.结论 该家系为典型的遗传性Leber病家系,mtDNA上G11778A位点突变可导致Leber病的发生,但并不是所有G11778A位点突变者均发生Leber病,也可能成为基因携带者.     

遗传性Leber视神经病变家系致病基因突变分析

目的 探讨遗传性Leber视神经病变(LHON)家系的致病基因突变位点.方法 家系调查研究.对LHON家系成员进行临床检查,抽取部分家系成员外周血提取基因组DNA,应用聚合酶链反应(PCR)和DNA序列测定法,检测家系成员线粒体DNA上的突变位点.结果 该家系3代14例成员中共有7例患者,其中男性2例,女性5例,家系图分析符合母系遗传特征.对其中4例患者及3例未发病家系成员进行线粒体DNA突变检测,显示4例患者及2例未发病家系成员携带G11778A位点突变.结论 线粒体DNA的G11778A突变位点是导致该家系患者发病的致病基因.对尚未发病的基因突变携带者进行早期干预治疗,有可能延缓或阻止疾病的发生与发展.     

Complete mitochondrial DNA sequence analysis in two southern Chinese pedigrees with Leber hereditary optic neuropathy revealed secondary mutations along with the primary mutation

AIM: To investigate mitochondrial factors associated with Leber hereditary optic neuropathy (LHON) through complete sequencing and analysis of the mitochondrial genome of Chinese patients with this disease. METHODS: Two unrelated southern Chinese families with LHON and 10 matched healthy controls were recruited, and their entire mitochondrial DNA (mtDNA) was amplified and sequenced with the universal M13 primer. Then DNA sequence analysis and variation identification were perfomed by DNAssist and Chromas 2 software and compared with authoritative databases such as Mitomap. RESULTS: Mutational analysis of mtDNA in these two Chinese pedigrees revealed one common LHON-associated mutation, G11778A (Arg→His), in the MT-ND4 gene. In addition, there were two secondary mutations in Pedigree 1: C3497T (Ala→Val), and C3571T (Leu→Phe) in the MT-ND1 gene, which have not been reported; and two secondary mutations occurred in Pedigree 2: A10398G (Thr→Ala) in the MT-ND3 gene, and T14502C (Ile→Val) in the MT-ND6 gene. Three polymorphisms, A73G, G94A and A263G in the mtDNA control region, were also found. CONCLUSION: Our study confirmed that the known MT-ND4*G11778A mutation is the most significant cause of LHON. The C3497T and C3571T mutations in Pedigree 1 were also both at hot-spots of MT-ND1; they may affect the respiratory chain in coordination with the primary mutation G11778A. In Pedigree 2, the two secondary mutations A10398G of MT-ND3 and T14502C of MT-ND6 may influence mitochondrial respiratory complex I, leading to the mitochondrial respiratory chain dysfunction which results in optic atrophy together with G11778A. Therefore, not only the common primary LHON mutation is responsible for the visual atrophy, but other secondary mtDNA mutations should also be considered when giving genetic counseling.     

Leber’s Hereditary Optic Neuropathy is Associated with Compound Primary Mutations of Mitochondrial ND1 m.3635G > A and ND6 m.14502 T > C

Purpose: To describe the clinical and molecular characteristics of a Chinese Leber hereditary optic neuropathy (LHON) pedigree with compound mitochondrial DNA (mtDNA) mutations of m.3635G?>?A and m.14502T?>?C.

Methods: A total of 22 individuals (2 affected, 20 unaffected) from a five-generation Chinese family with LHON underwent comprehensive ophthalmic examination, including visual acuity, slit lamp examination, fundoscopy, visual field examination and visual evoked potentials (VEP). The complete mtDNA genome of the two patients were amplified by polymerase chain reaction, sequenced using a Bigdye terminator v3.1 cycle sequencing kit and analyzed on an ABI 3700XL Genetic Analyzer.

Results: Two LHON patients in the family presented typical features of LHON: painless and progressive deterioration of bilateral vision, bilateral optic atrophy, centrocecal scotomata in both eyes and significant prolonged P100 latency and low amplitude potential in VEP. Compound primary mtDNA mutations of m.3635G?>?A and m.14502T?>?C were identified in these two patients and another 12 living matrilineal members of the pedigree. Haplogroup analysis showed the patients in this LHON family belonged to the N9b1 haplogroup. Modeled mutant structure showed the mutations altered the molecular local space conformation on the surface of ND1 and ND6.

Conclusions: Compound mtDNA mutations of m.3635G?>?A and m.14502T?>?C presented with low penetration, and the patients with these compound mutations exhibited mild visual impairment. The biological information analysis suggested that m.14502T?>?C might play a protective role in LHON associated with m.3635G?>?A. The haplogroup analysis indicated that the mtDNA haplogroup might be an important factor affecting the expression of LHON associated with m.3635G?>?A and/or m.14502T?>?C.     

中国人Leber遗传性视神经病变线粒体DNA突变频谱

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（mitochondrial DNA, mtDNA）3个原发致病基因突变的频谱及其遗传特征。 方法 分别用突变特异性引物聚合酶链反应(mutation-specific priming polymerase chain reaction, MSP-PCR)、异源双链-单链构象多态性（heteroduplex-single strand conformation polymorphism polymerase chain reaction,HA-SSCP ） 、限制性片段长度多态性(restriction fragment length polymorphisms,RFLP)和DNA测序等方法,对140个LHON家系的先证者（男120人,女20人）进行mtDNA 3个原发致病突变位点,即G11778A、G3460A和T14484C的检测,并对这些患者的家系进行遗传分析。 结果 在140例LHON 先证者中,130例（男113人,女17人）为G11778A位点突变,占92.9%;2例（男、女各1人）为G3460A位点突变,占1.4％;8例（男6人,女2人）为T14484C位点突变,占5.7%。 结论 中国人LHON患者mtDNA 3个原发致病突变中,以G11778A位点突变为主,少数为G3460A 和T14484C位点的突变。（中华眼底病杂志,2003,19：269-332）     

疑似LHON患者mtDNA突变规律及临床研究

目的:研究临床疑似Leber遗传性视神经病变(Leber’s hereditary optic neuropathy,LHON)患者的mtDNA突变规律及临床表现。方法:对2006-01/2012-01就诊于邢台市眼科医院符合病例入选标准的175例患者,按是否有家族史分为对照组及观察组,对照组患者口服维生素B1片、甲钴胺片治疗,观察组患者加用注射用甲泼尼龙琥珀酸钠,对两组患者抽取静脉血,进行mtDNA 11778,3460,14484三个原发突变位点及相关突变热点进行检测,分析其发病年龄、突变率、突变位点、logMAR最佳矫正视力。结果:观察组:男78例,女34例,年龄8～42(平均23±4.5)岁,mtDNA突变阴性者59例(52.7%),mtDNA突变阳性者53例(47.3%),其中G11778A突变41例(36.6%),T14484C突变5例(4.5%),G3460A突变2例(1.8%),另外尚有G15927A突变1例,A15951G突变1例,G11696A突变1例,G11778A+G11696A突变1例,G11778A+G3316A突变1例。mtDNA突变阴性者平均logMAR视力为1.11±0.31。对照组:男46例,女17例,年龄7～44(平均18±6.5)岁,G11778突变53例(84.1%),T14484C突变8例(12.7%),G3460A突变2例(3.2%),平均logMAR视力为1.13±0.32。结论:疑似LHON患者发病年龄较LHON患者偏大,mtDNA突变G11778A占多数,存在多个mtDNA同时突变及其它mtDNA位点突变;对糖皮质激素治疗不敏感,最佳矫正logMAR视力在1.1左右。     

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.     

The novel A4435G mutation in the mitochondrial tRNAMet may modulate the phenotypic expression of the LHON-associated ND4 G11778A mutation

PURPOSE: To investigating the role of mitochondrial haplotypes in the development of Leber's hereditary optic neuropathy (LHON) associated with the ND4 G11778A mutation in Chinese families. METHODS: A three-generation Chinese family with LHON was studied by clinical and genetic evaluation as well as molecular and biochemical analysis of mitochondrial (mt)DNA. RESULTS: This family exhibits a high penetrance and expressivity of visual impairment. The average age at onset was 13.9 years in this family. Of the family members, 86% of the male and 29% of the female matrilineal relatives had visual loss, with a wide range of severity, from blindness to nearly normal vision. Molecular analysis of mtDNA identified the homoplasmic ND4 G11778A mutation and 35 other variants, belonging to the Asian haplogroup D5. Of other variants, the novel homoplasmic A4435G mutation absent in 164 Chinese controls is localized at 3' end adjacent to the anticodon, at conventional position 37 (A37), of tRNAMet. The adenine (A37) at this position of tRNAMet is extraordinarily conserved from bacteria to human mitochondria. This modified A37 was shown to contribute to the high fidelity of codon recognition and to the structural formation and stabilization of functional tRNAs. In fact, the significant reduction of the steady state levels in tRNAMet was observed in cells carrying the both the A4435G and G11778A mutations but not cells carrying only the G11778A mutation. Thus, a failure in mitochondrial tRNA metabolism, caused by the A4435G mutation, may worsen the mitochondrial dysfunction associated with the primary G11778A mutation. CONCLUSIONS: The novel tRNAMet A4435G mutation has a potential modifier role in increasing the penetrance and expressivity of the primary LHON-associated G11778A mutation in this Chinese family.     

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.