遗传性共济失调线粒体DNA 3243、8993点突变的研究

目的研究线粒体DNA点突变与遗传性共济失调(HA)的关系。方法采用聚合酶链反应方法,扩增26例HA患者和35例健康对照者的外周血白细胞线粒体DNA,用限制片断长度多态性分析法检测有无A3243G、T8993G或T8993C点突变。结果所有HA患者和健康对照者均未检测到线粒体DNA点A3243G、T8993G或T8993C点突变。结论线粒体DNAA3243G、T8993G或T8993C基因突变导致HA的可能性不大。     

Leigh综合征的线粒体DNA突变分析

目的：了解中国人Leigh综合征的线粒体DNA（mtDNA）突变特点。方法：对12例LS患者用Southern杂交和PCR－限制性内切酶分析的方法检测有无mtDNA的缺失及T8993G、T8993C、T9176C、A8344G、A3243G等点突变。结果：在4例患者中发现mtDNA点突变，包括T8993G1例、T8993C1例、A8344G2例，定量分析表明突变型mtDNA的比例均较高，为87．2％－97．8％，未发现mtDNA的大片段缺失及T9176C、A3243G点突变。结论：LS在遗传方面有显著的异质性，根据不同的病因，临床表现略有差异。     

线粒体肌病和脑肌病患者骨骼肌细胞线粒体DNA缺失分析

目的为了检测线粒体肌病和脑肌病患者的骨骼肌细胞的线粒体ＤＮＡ的缺失情况。方法从６例原发性线粒体肌病和１例脑肌病患者的骨骼肌活检标本中，提取总ＤＮＡ，以线粒体ＤＮＡ全长为探针进行分子杂交。结果发现１例ＭＥＲＲＦ患者有５ｋｂ的线粒体ＤＮＡ基因缺失，另１例线粒体肌病患者有１５ｋｂ的线粒体ＤＮＡ基因缺失，剂量分析表明缺失型线粒体ＤＮＡ分别占总线粒体ＤＮＡ的１９．３％和１０．７％。结论线粒体ＤＮＡ基因缺失是线粒体疾病的重要病因之一     

线粒体DNA突变与线粒体脑肌病

本文简述了线粒体DNA的基本结构、功能及特性,并着重讨论线粒体DNA点突变与几种临床常见的线粒体疾病如Leber's病,MELAS,MERRF之间的联系及特异性线粒体DNA点突变的基因诊断意义。     

线粒体 DNA 与阿尔茨海默病的关系

阿尔茨海默病(AD)是最常见的与痴呆有关的神经退行性疾病。已证实家族聚集性 AD与淀粉样前体蛋白基因及早老素1、早老素2基因的突变有关,而迄今为止,仍未发现与散发性 AD 相关的致病基因。研究表明,线粒体 DNA(Mitochondrial DNA,mtDNA)突变可导致能量代谢障碍、氧化应激增多以及β淀粉样蛋白的积累,进而导致 AD 的发生、发展。然而,关于 mtDNA 突变或单倍群与 AD关系的研究结果是有争议的。现对 mtDNA 与 AD 的关系进行综述,以期指导后续研究。     

干细胞治疗感音神经性聋的研究理论及其临床应用进展******☆

背景：内耳毛细胞或螺旋神经元的丢失可引起感音神经性聋。内耳细胞死亡后,利用干细胞研究来恢复听力已成为近年来研究热点。目的：总结近年来干细胞向内耳细胞方向分化的体内外研究进展,对干细胞进行感音神经性聋后内耳细胞替代治疗的研究成果进行综述。方法：应用计算机检索Pubmed数据库(2000-01/2009-08),检索词为“inner ear,Stem cells”;应用计算机检索CNKI数据库(2000-01/2009-08),检索词为“内耳、干细胞”。结果与结论：计算机初检得到170篇文献,纳入与干细胞在感音神经性聋的细胞转化有密切关系的实验研究和综述,排除重复研究类文献,对符合条件的32篇文献进行汇总分析。不同类型干细胞具有向内耳细胞分化的能力,能够分化为神经源性细胞类型。干细胞移植到内耳结构中可以发生迁移、分化,并部分分化为损伤区域的细胞类型,为感音神经性聋听力恢复提供了一条治疗途径。如何使分化细胞发挥正常生理功能,移植到内耳后能否建立神经通路,是干细胞治疗感音神经性聋下一步研究方向。     

浙江温岭帕金森病线粒体DNA基因突变与多态性研究

目的 研究温岭散发性帕金森病(PD)线粒体DNA(mtNDA)基因突变与国人散发性PD相关性.方法 对88例散发性PD患者和60例正常健康人的基因位点G1719A、G4580A、C7028T进行扩增,将其异常结果进行基因测序,确定基因突变发生位点.结果 在PD患者G1719A附近有4例1711(G→A)1738(A→G),3例1738(A→G),1例1664(G→A)突变;在G4580A附近有1例4476(A→G),1例4638(A→G),1例4651(→T)突变;在C7028T附近有1例6984(C→T),1例6979( G→C) 6984(C→T),3例7083(C→),4例6963(G→A),1例6910(C→A)突变,共发现11种突变类型,对照组无发现突变位点.结论 散发性PD患者存在线粒体基因位点突变,预示线粒体基因突变参与了PD的发病过程.     

Alzheimer病患者线粒体DNA点突变的研究

目的旨在观察Alzheimer病(Alzheimerdisease,AD)患者线粒体DNA(mitochondrialDNA,mtDNA)上点突变的情况,并探讨mtDNA点突变与AD发生的关联性。方法入组了111例AD患者作为AD组和性别/年龄与之相匹配的正常老人117名组成对照组,应用PCR-RFLP的方法对被研究对象mtDNA上分别位于第4336、5460和8021三个位置的点突变情况进行检测。结果第4336位置上的碱基未发现存在突变的现象。第8021位置上的碱基仅在正常老人组内检测到1例突变型,其余均为野生型。在第5460位置上对照组突变率为2.6%(3/117),AD老人组中突变率为6.3%(7/111),显著性检验χ2=1.902,P=0.168。结论在我国上海汉族人群中线粒体DNA上第4336位置上可能不存在点突变的现象,第8021位置上突变也很少发生,在第5460位置上的碱基可能出现A或T的点突变,但这种突变的发生可能与AD的发生无直接关联。     

Alzheimer病线粒体DNA突变分子生物学研究进展

脑能量代谢降低为AD发病的危险因素之一 ,而线粒体是细胞能量储存和供给的重要场所。近年研究认为 ,线粒体DNA突变与AD的发病有关 ,本文就线粒体DNA突变在AD发病中的致病作用予以综述     

Leber遗传性视神经病的线粒体基因突变及临床特征

目的　了解Leber遗传性视神经病 (LHON)线粒体基因突变及其临床特征。方法　采用PCR法扩增96例视神经病变患者mtDNA中ND1、ND4、ND6上的 3个片段后 ,用 377测序仪对mtDNA上 11778、346 0、14 4 84位点进行序列分析确定有无碱基突变。结果　 96例患者中 4 0例 (41 7% )线粒体基因突变 ,其中男性 34例 (85 % ) ,女性 6例 (15 % ) ;34例 (85 % )为 11778位点突变 ,2例 (5 % ) 346 0位点突变 ,4例 (10 % ) 14 4 84位点突变 ;346 0及 14 4 84突变均为散发病例 ;有家族史者突变表达占 87 0 % (2 0 /2 3) ,无家族史者突变占 2 7 4 % (2 0 /73) ;头颅MR显示 11778突变者中 3例有脑白质区病灶 ,1例LHON合并垂体瘤 ;12例突变阳性者检查脑脊液 ,11例有炎性脱髓鞘改变。结论　LHON以 11778突变常见 ;起病及病程多样化、散发病例比例较高、眼底微血管病改变不易发现、脑脊液改变与炎性脱髓鞘雷同导致LHON在临床上易漏诊误诊 ,应尽早行突变检测明确诊断。     

线粒体基因G13513A突变导致的线粒体脑肌病六例临床表型分析

目的 报告6例mtDNA G13513A点突变引起的线粒体脑肌病患者的临床、影像学特点,总结mtDNA G13513A突变所致的线粒体病的临床表型.方法 对35例mtDNA常见突变(包括大片段缺失及A3243G、T3271C、A8344G、T8993G/C点突变)检查为阴性的线粒体脑肌病患者,用线粒体DNA全长测序和(或)聚合酶链反应-限制性片段长度多态法检测mtDNA G13513A点突变,分析阳性患者的临床特点,复习文献报道的mtDNA G13513A所致线粒体病的病例.结果 35例患者中有6例存在mtDNA G13513A突变.该6例患者均出现偏盲、轻偏瘫或偏身感觉障碍等卒中样发作表现,其中3例成人发病者以卒中样发作为主要症状,伴随癫痫、头痛、身材矮小、神经性耳聋等,头颅MRI显示以顶-枕-颢叶受累为主的大片病灶,符合成人型线粒体脑肌病伴高乳酸血症和卒中样发作(MELAS)的临床和影像学特点;3例青少年发病者除卒中样发作外,还有构音障碍、共济失调、眼外肌瘫痪等脑干受累的症状,MRI检查可见枕-颞叶大脑皮质非对称性病灶,以及双侧基底节和脑干的对称性病灶,符合青少年型MELAS-Leigh叠加综合征的临床和影像学特点.肌肉病理检查在5例患者发现不整红边纤维.经复习文献,发现mtDNA G13513A突变患者还存在婴幼儿型Leigh或Leigh样综合征表型.结论 mtDNA G13513A点突变是线粒体脑肌病较常见的致病性突变,主要导致Leigh综合征、MELAS-Leigh叠加综合征或MELAS综合征,其临床表型具有年龄依赖性.

Abstract：

Objective To report 6 Chinese patients with mitochondrial encephalomyopathy caused by mitochondrial DNA(mtDNA)G13513A mutation and discuss the mitochondrial phenotype associated with this mutation based on the data of our patient series as well as the reports by others.Methods Direct sequencing of polymerase chain reaction(PCR)products or PCR-RFLP analysis Was performed to screen mtDNA G13513A mutation in 35 cases with mitoehondrial encephalomyopathy.who carried no mtDNA common mutations(1arge 8eale deletion,A3243G,T3271 C,A8344G,or T8993G/C).The clinical features,MRI changes were retrospectively collected and analyzed.Published studies of all patients with mtDNA G13513A mutation were also reviewed.Results Six patients were identified carrying mtDNA G13513A mutation.All patients presented stroke-like episodes with hemianopsia.hemiparesis or hemiparesthesia.Three adult patients presented clinical and radiological features of adult-onset mitochondrial myopathy,encephalopathy,lactic acidosis,and stroke-like episodes(MELAS),including stroke-like episodes,epilepsy,headache,short stature,sensorineural deafness,multifocal lesions on parietal,occipital and temporal lobes on cranial MRI scans.Three iuvenile.onset patients presented the clinical and brain MRI features of MELAS-Leigh syndrome(LS)overlap syndrome.In addition to the stroke-like episodes,they also showed brain stem lesions with dysarthria,ataxia,and ophthalmopJegia. Brain MRI revealed asymmetrical lesions in the cortex of the oecipital and temporal lobes,as well as symmetrical lesions in the bilateral basal ganglia and brainstem.Muslce biopsy showed ragged redfibem in 5 patients.The infant-onset LS or Leigh-like syndrome with mtDNA G135 13A was described in the English literature.Conclusions mtDNA G13513A mutation is a common pathogenic mutmion for mitochondrial encephalomyopathy,which can result in Leigh syndrome,MELAS-LS overlap syndrome and adult MELAS.The onset of various phenotypes is relatively age-dependent.     

腓骨肌萎缩症伴神经性耳聋一家系临床和分子遗传学分析

目的探讨一个X连锁腓骨肌萎缩症(CMTX)伴常染色体隐性遗传的神经性耳聋家系的临床特点并研究其分子遗传学病因。方法对9名家系成员进行详细的临床检查，先证者进行了神经肌电图、听觉诱发电位和神经活检，3名耳聋患者进行电测听检查。运用聚合酶链反应一单链构象多态性分析技术(PCR-SSCP)结合直接测序法进行间隙连接蛋白32(eonnexin32)的突变分析，直接测序法进行间隙连接蛋白26(connexin26)的突变分析。结果家系中3名腓骨肌萎缩症患者为X连锁显性遗传，3名神经性耳聋患者为常染色体隐性遗传，其中1名患者同时出现腓骨肌萎缩症和神经性耳聋的临床症状。CMTX由connexin32错义突变C223T(Arg75Trp)引起。耳聋症状与connexin32点突变无共分离现象，对connexin26直接测序亦未发现突变，耳聋的致病基因有待进一步探讨。结论该家系腓骨肌萎缩症和耳聋分别由不同基因突变引起，这种在一个家系中同时出现两种不同遗传方式，不同致病基因的遗传病罕有报道。     

线粒体脑肌病伴高乳酸血症和卒中样发作综合征与一种新的线粒体DNA基因突变

目的 检测1例线粒体脑肌病伴高乳酸血症和卒中样发作综合征(MELAS)患者脑组织和外周血线粒体DNA(mtDNA)的基因突变类型。方法 应用聚合酶链反应-限制性片段长度多态性(PCR—RFLP)方法对这例MELAS患者脑组织和外周血mtDNA的A3243G点突变进行检测，对检测过程中发现的异常扩增产物进行DNA测序分析。结果 该例MELAS患者脑组织和外周血白细胞PCR扩增产物行聚丙烯酰胺凝胶电泳时产生了两条带，一条为494bp，另一条为218bp。494bp的扩增产物是目的片段，而218bp的片段是一种异常扩增产物。我们对218bp的PCR扩增产物进行测序，发现在mtDNA3314—3589之间有276bp的碱基缺失。结论 mtDNA3314-3589位点之间276bp的碱基缺失可能是导致MELAs的一种新的基因突变类型。     

线粒体DNA G13513A突变所致线粒体脑肌病伴高乳酸血症和脑卒中样发作/Leigh重叠综合征

目的 报道1例线粒体DNA G13513A点突变所致线粒体脑肌病伴高乳酸血症和脑卒中样发作(MELAS)/Leigh重叠综合征的临床、影像学、神经病理学改变特点.方法 患者为22岁女性,反复出现头痛、视力下降和肢体抽动11年,因癫疴持续状态而死亡.之前多次MRI检查发现大脑皮质大片长T1长T2异常信号,病灶从枕叶开始,逐渐波及顶叶,疾病后期累及双侧基底节区及脑干灰质核团.对患者进行脑局部尸体解剖检查,取肌肉标本进行线粒体基因检查.结果 各个脑叶皮质以及双侧纹状体和中脑四叠体可见多灶性层样分布的海绵样改变,出现胶质增生、毛细血管内皮细胞增生以及较多单核细胞反应,其中双侧枕叶和顶叶的皮质全层以及皮质下白质被严重累及.基因检查显示线粒体还原型烟酰胺腺嘌呤二核苷酸脱氢酶5基因存在G13513A点突变.结论 MELAS/Leigh重叠综合征的临床表现以皮质损害为主,影像学改变提示病变先累及大脑皮质,而后累及脑干和基底节区,出现海绵样改变伴随毛细血管增生.     

Connexin 26: required for normal auditory function

A single base deletion mutation, 35delG, in the gene (GJB2/DFNB1)(OMIM 121011/220290) encoding the gap junction protein, connexin 26 is the most important single cause of genetic hearing loss in European and American populations. It is the cause of one of the most common human genetic disorders with a frequency similar to cystic fibrosis. Mutations in this connexin are associated with skin disorders.     

应用实时荧光定量聚合酶链反应结合突变阻滞形成系统进行线粒体脱氧核糖核酸A3243G突变负荷检测

目的 应用实时荧光定量PCR结合突变阻滞形成系统(RT ARMS-qPCR)技术检测线粒体DNA A3243G突变负荷,并探讨线粒体脑肌病伴高乳酸血症和脑卒中样发作(MELAS)综合征患者不同组织中A3243G突变负荷的分布情况.方法 分别构建含线粒体DNA3243位点的野生型(A)和突变型(G)序列的质粒,将这2种质粒按一定比例混合构建成13个含有不同A3243G突变负荷的标准对照,应用PCR-限制性片段多态性技术(RFLP)和RT ARMS-qPCR技术检测13个标准对照及存在A3243G突变的7例MELAS患者、1名携带者以及53名健康对照的外周血、肌肉、毛发及尿沉渣等组织的A3243G突变负荷.结果 标准对照的突变负荷经PCR-RFLP和RT ARMS-qPCR检测的结果均与预期值呈直线相关,决定系数分别为R21=0.885、R22=0.991,RT ARMS-qPCR检测的结果更接近预期值;7例MELAS患者及1名携带者不同组织的突变负荷经RT ARMS-qPCR检测的结果比经PCR-RFLP检测出的高,且RT ARMS-qPCR比PCR-RFLP更容易检测出低负荷的A3243G突变,并发现MELAS患者的肌肉、尿沉渣、头发的A3243G突变负荷均高于外周血.结论 应用RT ARMS-qPCR可以快速、灵敏、准确地检测不同组织的A3243G突变及其突变负荷.     

Spectrum of the mitochondrial DNA mutations of Leber's hereditary optic neuropathy in Koreans

We investigated 14 primary mitochondrial DNA (mtDNA) mutations at nucleotide positions (nps) 3460A, 4160C, 5244A, 9101C, 9804A, 10663C, 11778A, 13730A, 14459A, 14482G, 14484C, 14495G, 14498T, and 14568T, and one common secondary mutation at np 15257A, in 82 Korean patients with suspected Leber's hereditary optic neuropathy (LHON). Only three kinds of LHON mutations were identified in 60 (73 %) of the 82 probands, these being the 11778A, 14484C, and 3460A mutations with 46 (56 %), 13 (16 %), and 1 (1 %) cases, respectively. None of the other mtDNA mutations was detected. Of the 60 probands with LHON positive mutations, 19 (32 %) had relevant family histories. Heteroplasmy was determined in 2 (4 %) of the 46 probands with the 11778A mutation and 1 (8 %) of the 13 probands with the 14484C mutation. In conclusion, the 11778A mutation was the most common cause (56 %), with a high prevalence of the 14484C and a lower prevalence of the 3460A mutations being characteristic of Korean patients with LHON. The 3460A mutation especially showed a remarkable racial difference from that in Caucasians. With the exceptions of the 3460A, 11778A, and 14484C, the mutations screened may not be involved in the pathogenesis of LHON in Koreans and may not have a synergistic effect on its clinical expression. Received: 20 June 2002, Received in revised form: 25 September 2002, Accepted: 9 October 2002 Correspondence to Sung Sup Park     

Clinical heterogeneity associated with mitochondrial DNA depletion in muscle

We studied 10 patients with a variable degree of mtDNA depletion in muscle. Seven patients showed a clear-cut myopathic pattern, while the three remaining had brain involvement. There was no relationship between age at onset and relative mtDNA copy number in muscle, but we found an apparent correlation between clinical severity and degree of muscle mtDNA depletion. Muscle morphology showed that mtDNA depletion was associated with mitochondrial proliferation and cytochrome c oxidase negative fibers. Biochemical studies revealed single or combined defects of mtDNA-dependent respiratory chain complexes. Our data indicate that patients with mtDNA depletion may have a more variable age at onset and clinical evolution and wider phenotype than previously thought. The diagnosis of this condition, so far regarded as rare, may have been overlooked to some extent.     

Widespread tissue distribution of multiple mitochondrial DNA deletions in familial mitochondrial myopathy

We used Southern blot analysis and the polymerase chain reaction to analyze the tissue distribution of multiple mitochondrial DNA (mtDNA) deletions in a 45-year-old man with familial mitochondrial myopathy. Southern blots showed two major types of abnormal mtDNA with approximately 4- and 8-kilobase deletions in the skeletal and extraocular muscles. The amount of muscle mtDNA with deletions correlated approximately with the severity of muscle involvement. The polymerase chain reaction showed multiple mtDNA deletions even in clinically asymptomatic tissues, the pattern of which differed with the type of tissue. Nucleotide sequences of several mtDNAs with deletions showed that the deletions were flanked by direct repeats consisting of 3 to 12 nucleotides. Leukocytes from the patient's affected sister and his mother exhibited the same mtDNA deletion pattern. Most of the same deletions were present in leukocytes obtained from the patient's father. © 1994 John Wiley & Sons, Inc.