线粒体脑肌病伴高乳酸血症和卒中样发作综合征的线粒体DNA突变特点

目的探讨线粒体脑肌病伴高乳酸血症和卒中样发作(MELAS综合征)的分子遗传学特点.方法用聚合酶链反应-限制片段长度多态性(PCR-RFLP)方法检测来自7个家庭的9例MELAS患者及其部分母系亲属的肌肉和(或)外周血细胞的mtDNA的A3243G和T3271C点突变,并进行突变型mtDNA的定量.结果在9例患者和1例亲属的肌肉和(或)外周血细胞中检测到A3243G点突变,未检测到T3271C突变.在这10例A3243G阳性标本中,外周血细胞(9例)的突变型mtDNA的比例为26.8%～50.3%;肌肉组织(4例)的突变型mtDNA的比例为46.8%～61.0%;对3例患者同时进行了肌肉和血细胞标本的检测,突变型mtDNA的比例肌肉组织均高于血细胞.对6个家庭的部分母系亲属的血细胞研究表明:只有1例先证者的同胞有此突变;另外3例先证者的母亲及2例先证者的同胞均未检测到此突变.另外有2例先证者的儿子临床表现符合MELAS,血中也检测到此突变.结论 mtDNA A3243G突变在本组MELAS综合征中的发生率较高,并且可在不同组织中检测到此突变,与国外文献报道一致;但国外报道多为母系遗传,而我们的病例以散发的居多,推测是由于新生突变所致.     

线粒体脑肌病伴高乳酸血症和卒中样发作综合征的线粒体DNA突变特点

目的 探讨线粒体脑肌病伴高乳酸血症和卒中样发作（MELAS综合征）的分子遗传学特点。方法 用聚合酶链反应-限制片段长度多态性（PCR-RFLP）方法检测来自7个家庭的9例MELAS患者及其部分母系亲属的肌肉和（或）外周血细胞的mtDNA的A3243G和T3271C点突变,并进行突变型mtDNA的定量。结果 在9例患者和1例亲属的肌肉和（或）外周血细胞中检测到A3243G点突变,未检测到T3271C突变。在这10例A3243G阳性标本中,外周血细胞（9例）的突变型mtDNA的比例为26.8%-50.3%;肌肉组织（4例）的突变型mtDNA的比例为46.8%-61.0%;对3例患者同时进行了肌肉和血细胞标本的检测,突变型mtDNA的比例肌肉组织均高于血细胞。对6个家庭的部分母系亲属的血细胞研究表明：只有1例先证者的同胞有此突变;另外3例先证者的母亲及2例先证者的同胞均未检测到此突变。另外有2例先证者的儿子临床表现符合MELAS,血中也检测到此突变。结论 mtDNA A3243G突变在本组MELAS综合征中的发生率较高,并且可在不同组织中检测到此突变,与国外文献报道一致;但国外报道多为母系遗传,而我们的病例以散发的居多,推测是由于新生突变所致。     

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.     

线粒体脑肌病伴高乳酸血症和脑卒中样发作综合征一家系临床特征及线粒体基因A3243G位点点突变异质性水平

目的 调查1个疑似患有母系遗传性线粒体脑肌病伴高乳酸血症和脑卒中样发作(MELAS)综合征家系的临床表现、生物化学检测数据和影像学资料,并探索其与血细胞线粒体基因突变异质性水平的关联性.方法 收集先证者和11位其母系家系成员的一般情况、抽搐及脑卒中样发作等病史,检测家系成员的血常规和运动前后血浆乳酸水平等生化指标,并做头颅磁共振检查.用聚合酶链反应(PCR)-限制性内切酶片段长度多态和DNA测序法检测其成员是否存在线粒体基因组A3243G点突变,并用荧光实时定量PCR定量该突变的水平.结果 该家系部分成员存在抽搐、脑卒中样发作和高乳酸血症等MELAS综合征典型症状,以及身材矮小、运动不耐受和发热、偏头痛等非典型症状.发作期头颅磁共振成像符合MELAS综合征的典型特点,且普遍存在小脑萎缩.母系亲属均存在线粒体基因的A3243G位点点突变,突变异质性水平越高,症状越典型且严重.结论 该调查家系确诊母系遗传性MELAS综合征,其致病基因为线粒体A3243G点突变.外周血血细胞线粒体基因突变异质性水平与亲缘关系、抽搐早现性和血乳酸值等临床表型存在相关性.     

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。     

粒脑肌病伴高乳酸血症和卒中样发作患者的临床、病理和线粒体DND突变分析

目的 能量代谢障碍是青年期卒中的重要病因之一,该研究总结线粒体脑肌病伴高乳酸血症和卒中样发作(mitochondrial encephalomyopathy with lactic acidosis and stroke-like episode.MELAS)患者的临床,病理特征,分析线拉体DNA突变,望能有助于提高对该病的认识、改进青年卒中的诊治.方法 回顾分析15例临床特征和骨骼肌病理符合MELAS的患者.分析线粒体脱氧核糖核酸(mitochondrial DNA,mtONA)突变,多聚酶链反应(polymerase chain reaction,PCR)后直接测序分析mtDNA热点突变,并对未发现热点突变的患者进行全mtDNA序列分析.结果 15例患者的临床表现以头痛和卒中样发作,癫癎发作为主要表现,病灶以皮层尤其枕叶、顶叶为多,磁共振成像(magnetic resonance imaging,MRI)有一定特征,生化检查发现血乳酸、乳酸/丙酮酸此值升高,肌酶轻度升高,病理上以破碎红纤维(ragged-red fibers,RRF)和细胞色素C氧化酶(cytochrome C oxidase,COX)/琥珀酸脱氲酶(Succinate dehydrogenase,SDH)蓝染纤维为主要特征,电镜下显示线粒体增多,线拉体内包涵体.11例由亮氨酸转运核搪核酸(mitochondrial tRNA for leucine,MTTL1,tRNA1)基因突变导致,细胞色素C氧化酶亚单位3(Cytochrome c oxidase subunit 111,C05)基因9469C/T突变,线粒体ATP合成酶亚单位8(Subunit 8 of mitochondrial ATP synthase.ATP8)基因8469A/G突变和细胞色素C氧化酶亚单位1(Cytochrome c oxidase subunit 1,C01 or MTC01)基因62553T/C突变各1例,1例患者无任何mtDNA突变.结论 MELAS是青年期卒中重要原因之一,肌肉活检是临床诊断的主要手段,mtDNA突变分析尤其是热点突变(MTTL1,5245G和MTTL1*5271C)分析对于确诊有重要价值.     

线粒脑肌病伴高乳酸血症和卒中样发作患者的临床、病理和线粒体DNA突变分析

目的 能量代谢障碍是青年期卒中的重要病因之一,该研究总结线粒体脑肌病伴高乳酸血症和卒中样发作（mitochondrial encephalomyopathy with lactic acidosis and stroke－like episode,MELAS）患者的临床、病理特征,分析线粒体DNA突变,望能有助于提高对该病的认识、改进青年卒中的诊治。方法 回顾分析15例临床特征和骨骼肌病理符合M E L AS的患者。分析线粒体脱氧核糖核酸（mitochondrial DNA,mtDNA）突变,多聚酶链反应（polymerase chain reaction,PCR）后直接测序分析mtDNA热点突变,并对未发现热点突变的患者进行全mtDNA序列分析。结果 15例患者的临床表现以头痛和卒中样发作、癫发作为主要表现,病灶以皮层尤其枕叶、顶叶为多,磁共振成像（magnetic resonance imaging,MRI）有一定特征,生化检查发现血乳酸、乳酸/丙酮酸比值升高,肌酶轻度升高,病理上以破碎红纤维（ragged-red fibers,RRF）和细胞色素C 氧化酶（cytochrome C oxidase,COX）/琥珀酸脱氢酶（Succinate dehydrogenase,SDH）蓝染纤维为主要特征,电镜下显示线粒体增多,线粒体内包涵体。11例由亮氨酸转运核糖核酸（mitochondrial tRNA for leucine,MTTL1,tRNA1）基因突变导致,细胞色素C氧化酶亚单位3（Cytochrome c oxidase subunit Ⅲ,CO3）基因9469C/T突变,线粒体ATP合成酶亚单位8（Subunit 8 of mitochondrial ATP synthase,ATP8）基因8489A/G突变和细胞色素C氧化酶亚单位1（Cytochrome c oxidase subunit Ⅰ,COⅠ or MTCO1）基因6253T/C突变各1例,1例患者无任何mtDNA突变。结论 MELAS是青年期卒中重要原因之一,肌肉活检是临床诊断的主要手段,mtDNA突变分析尤其是热点突变（MTTL1*3243G和MTTL1*3271C）分析对于确诊有重要价值。     

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。     

抗线粒体抗体在线粒体脑肌病伴高乳酸血症和脑卒中样发作综合征患者肌纤维中的免疫组织化学表达

目的 探讨抗线粒体抗体(anti-mitochondrial antibody,AMA)在线粒体腩肌病伴高乳酸血症和脑卒巾样发作(MELAS)综合征患者肌肉组织中的免疫组织化学表达特点及其诊断价值.方法 收集经临床、病理以及基因检测确诊的MELAS综合征患者10例,以2名肌肉病理正常者和3例肌肉活体组织检查发现坏死肌纤维的非线粒体病患者作为对照组,对所有15例肌肉冰冻组织标本行AMA免疫组织化学染色.结果 普通光镜下观察发现MELAS患者骨骼肌AMA免疫组织化学染色可见大量不整棕褐色肌纤维(ragged brown fibers,RBF),其形态类似MGT染色下的不整红边纤维(ragged red fibers,RRF).而对照组未发现RBF.结论 AMA免疫组织化学下的RBF是线粒体异常增生的特异性表现,同MGT染色下的RRF类似,可以作为诊断线粒体病异常线粒体的病理学指标.     

线粒体脑肌病伴乳酸酸中毒和卒中样发作综合征

线粒体病是一组线粒体基因或细胞核基因突变导致线粒体结构和功能异常,并由此引起多系统损害的疾病,以需氧量较高的脑和肌肉受累为主[1,2]。其临床表现多样,主要有线粒体脑肌病伴乳酸酸中毒和卒中样发作(MELAS)综合征、慢性进行性眼外肌瘫痪(CPEO)、肌阵挛性癫疒间伴肌肉破碎红纤维(MERRF)综合征、亚急性坏死性脑脊髓病(Leigh病)和以眼     

Mitochondrial encephalomyopathy with lactic acidosis and stroke-like episodes correlates with heteroplasmic mutations of mitochondrial DNA 3243 A single-case genealogy analysis

BACKGROUND: Mitochondrial encephalomyopathy with lactic acidosis and stroke-like episodes (MELAS) is a common syndrome of mitochondrial diseases caused primarily by a mutation from adenine to guanine at mitochondrial DNA 3243. However, the correlation between heteroplasmic mutations and clinical characteristics of hereditary MELAS syndrome is unclear. OBJECTIVE: To survey the clinical behaviors, biochemical outcomes, and imaging data in a patient with suspected MELAS syndrome by maternal inheritance, and to investigate the correlation with heteroplasmic mutations of hemocyte mitochondrial DNA. DESIGN, TIME AND SETTING: A case analysis based on hereditary family surgery was performed in the Enliang Hospital of Anshan, Taian County, and biochemical tests and gene diagnosis were erformed at the Department of Laboratory and Institute of Neurology, the First Affiliated Hospital of China Medical University, between March and September 2009. ARTICIPANTS: A 22-year-old female patient with MELAS syndrome was diagnosed in the First Affiliated Hospital of China Medical University in January, 2009. She had five males and seven females in her maternal family. METHODS: We obtained stroke and convulsion history in the patient and her family, as well as erforming routine blood tests, plasma lactic acid levels before and after movement, and magnetic resonance of the head. A mutation at m.3243A > G was verified using polymerase chain reaction-restriction fragment length polymorphism and DNA sequencing, and quantitated using real-time polymerase chain reaction. MAIN OUTCOME MEASURES: Correlation of clinical behaviors and biochemical outcomes, as well as imaging data with heteroplasmic mutations in family members with typical and atypical MELAS syndrome. RESULTS: Some family members had typical symptoms of convulsion, stroke, and MELAS syndrome, as well as atypical symptoms of microsomia, movement intolerance, febrile, and migraine. Magnetic resonance of the head was consistent with typical imaging data of MELAS syndrome during attacks, and family members showed cerebellar atrophy. A heteroplasmic mutation of mitochondrial DNA 3243 occurred in all family members, although higher levels caused severe typical symptoms. The age of first-onset convulsion was negatively correlated with level of heteroplasmic mutation (r= -0.852, P< 0.05), but lactic acid was positively correlated with mutation levels (before movement, r= 0.945, P< 0.001; after movement, r= 0.945, P< 0.001). CONCLUSION: MELAS syndrome was diagnosed in this family by maternal inheritance, and the etiological factor was a mutation of mitochondrial A3243G. The level of heteroplasmic mutation correlated with anticipated convulsion and lactic acid levels.     

线粒体脑肌病伴高乳酸血症和卒中样发作的诊断

目的 分析总结线粒体脑肌病伴高乳酸血症和卒中样发作(MELAS)的临床表现和辅助检查结果,探讨在MELAS诊断中存在的问题,提出MELAS早期临床诊断的可行性.方法 归纳总结34例MELAS患者的临床表现,寻找对MELAS患者相对特异的症状组合.同时总结分析各项辅助检查结果,结合文献复习解读血和脑脊液的乳酸水平、神经影像、肌肉活体组织检查(活检)和基因检查对于MELAS诊断的意义和局限性.结果 本组患者最常见的临床表现依次为:癫癎发作、头痛、智能下降、卒中样发作、发育异常、四肢无力和易疲劳、眼肌麻痹.血空腹乳酸或运动后乳酸升高23例(67.6%).32例头颅MRI异常的患者最常见的受累部位依次为枕叶、顶叶、颞叶、基底节、额叶、小脑和深部白质.32例患者行肌肉活检,有阳性发现的共24例(75%),阴性的8例(25%).14例患者行基因检查,9例发现A3243G位点突变,5例未发现该位点突变.结论 认识MELAS的各种临床表现,争取在卒中样发作出现前早期诊断是完全可行的.     

线粒体脑肌病伴高乳酸血症和卒中样发作综合征的影像学特征及动态演变

目的探讨线粒体脑肌病伴高乳酸血症和卒中样发作(MELAS)综合征的影像学特点及其动态演变过程。方法收集2011年1月-2016年2月我院经肌肉病理确诊的21例MELAS综合征的资料,对他们的头部CT、MRI、增强MRI、MRA和MRS表现进行回顾性分析。结果 19例患者行头部CT,其中8例显示双侧基底节区对称性钙化。卒中样发作急性期头部磁共振主要表现为T_1WI低信号、T_2WI和FLAIR高信号,DWI高信号或等信号,ADC高信号或低信号;增强MRI未见明显强化或线状强化,MRA未见明显异常,MRS可见N-乙酰天门冬氨酸峰(NAA)下降、乳酸峰(Lac)明显升高。19例(90.5%)病灶累及2个及2个以上脑叶,最常累及的部位是枕叶、颞叶和顶叶。病灶呈层状坏死,分布不符合脑血管的支配区域,动态观察具有"可逆性"、"游走性"和"进展性"。结论 MELAS综合征临床表现复杂,神经影像学具有一定的特征性,具有重要诊断价值。充分认识这些特征,有助于早期诊治、减少误诊。     

Clinicopathological findings of a mitochondrial encephalopathy,lactic acidosis,and stroke‐like episodes/Leigh syndrome overlap patient with a novel m.3482A>G mutation in MT‐ND1

We report clinicopathological findings of a patient with mitochondrial encephalopathy, lactic acidosis, and stroke‐like episodes/Leigh syndrome (MELAS/LS) associated with a novel m.3482A>G mutation in MT‐ND1. A 41‐year‐old woman had experienced multiple stroke‐like episodes since age 16. She developed akinetic mutism two months before admission to our hospital. Neurological examination revealed akinetic mutism, bilateral deafness, and muscular atrophy. Cerebrospinal fluid tests revealed elevated pyruvate and lactate levels. Fluid‐attenuated inversion recovery images on magnetic resonance imaging showed hyperintense areas in the right frontal and both sides of temporal and occipital lobes, both sides of the striatum, and the midbrain. Muscle biopsy revealed strongly succinate dehydrogenase‐reactive blood vessels. L‐arginine therapy improved her consciousness and prevented further stroke‐like episodes. However, she died from aspiration pneumonia. Postmortem autopsy revealed scattered infarct‐like lesions with cavitation in the cerebral cortex and necrotic lesions in the striatum and midbrain. The patient was pathologically confirmed as having MELAS/LS based on two characteristic clinicopathological findings: presenting MELAS/LS overlap phenotype and effectiveness of L‐arginine treatment.     

中国线粒体脑肌病伴高乳酸血症和卒中样发作的诊治专家共识

线粒体脑肌病伴高乳酸血症和卒中样发作(MELAS)是一种由线粒体基因或核基因突变导致的,以卒中样发作、癫痫发作、认知与精神障碍、高乳酸血症、肌肉疲劳无力为主要临床特点的多系统代谢性疾病,其临床、病理特点和治疗策略具有一定的特殊性。为规范该病的诊治,结合国内外对该病的研究进展,专家组经反复讨论、修订,撰写了中国MELAS的诊治专家共识,从临床表现、家族史、辅助检查、诊断和鉴别诊断、治疗和护理、遗传咨询几大方面总结了该病的特点,供广大临床和科研工作者参考。