一种新的线粒体DNA基因突变:线粒体脑肌病伴高乳酸血症和卒中样发作综合征1例基因与残障特征分析

背景线粒体脑肌病伴高乳酸血症和卒中样发作综合征(MELAS)是线粒体脑肌病中最常见的一种临床类型,多种线粒体基因突变均可导致MELAS.目的探讨1例MELAS患者的临床表现和线粒体基因突变的关系.设计临床、病理和基因分析对照研究.地点和对象实验在解放军济南军区总医院神经内科病房、神经病理实验室和神经分子生物学实验室进行.患者,男,13岁,因发作性头痛、呕吐,肢体抽搐1个月于2001-06-04入院,入院后逐渐出现失明和智能减退.血乳酸和丙酮酸水平升高,临床诊断MELAS.干预对患者行头颅MRI检查、脑活检病理检查和线粒体基因分析.主要观察指标临床表现特点、MRI病变特征、脑组织病理改变特点以及线粒体基因突变类型.结果患者不存在能引起MELAS的较常见的突变,但在线粒体3314～3589之间有276 bp的碱基缺失.结论线粒体DNA 3314～3589位点之间276 bp的碱基缺失可能是能够导致MELAS的一种新的基因突变类型,也是导致患者出现失明、癫痫和痴呆的原因.     

伴小脑萎缩的线粒体脑肌病MELAS一例

线粒体脑肌病伴高乳酸血症和卒中样发作（MELAS）是一种少见的遗传性疾病,可累及机体多系统。该病主要临床表现为头痛、癫痫、耳聋、皮质盲及认知功能下降等。MELAS呈卒中样发作,临床易误诊为脑梗死及脑炎,目前尚缺乏特效治疗方法。该文报道1例33岁女性MELAS 患者,其以突发头痛、视物不清为首发症状,伴有不完全感觉性失语、听力下降、不能耐受疲劳,急诊颅脑CT显示双侧小脑半球萎缩,入院后经外周血基因检查明确MELAS诊断,予辅酶Q10胶囊、艾地苯醌及维生素E治疗。患者病情好转后出院,随访3个月病情稳定。该病例提示临床医师应提高对MELAS的认识,注意鉴别诊断,避免漏诊或误诊。     

一种新的线粒体DNA基因突变：线粒体脑肌病伴高乳酸血症和卒中样发作综合征1例基因与残障特征分析

背景：线粒体脑肌病伴高乳酸血症和卒中样发作综合征(MELAS)是线粒体脑肌病中最常见的一种临床类型，多种线粒体基因突变均可导致MELAS。目的：探讨1例MELAS患者的临床表现和线粒体基因突变的关系。设计：临床、病理和基因分析对照研究。地点和对象：实验在解放军济南军区总医院神经内科病房、神经病理实验室和神经分子生物学实验室进行。患者，男，13岁，因发作性头痛、呕吐，肢体抽搐1个月于2001-06-04入院，人院后逐渐出现失明和智能减退。血乳酸和丙酮酸水平升高，临床诊断MELAS。干预：对患者行头颅MRI检查、脑活检病理检查和线粒体基因分析。主要观察指标：临床表现特点、MRI病变特征、脑组织病理改变特点以及线粒体基因突变类型。结果：患者不存在能引起MEIAS的较常见的突变，但在线粒体3314—3589之间有276bD的碱基缺失。结论：线粒体DNA3314—3589位点之间276bp的碱基缺失可能是能够导致MEIAS的一种新的基因突变类型，也是导致患者出现失明、癫痫和痴呆的原因。     

质子磁共振波谱对MELAS诊断的初步评价

目的探讨质子磁共振波谱(1HMRS)在MELAS型线粒体脑肌病中的特点及其诊断价值。方法7例临床诊断为线粒体脑肌病的患者行MRI及1HMRS检查,分析其MRS检查技术、谱线特点、与临床实验室检查的关系。结果7例患者MRI脑内均有异常表现,异常信号主要出现在双侧枕叶、顶叶、颞叶,其中4例合并基底节受累,2例额叶轻度受累,1例合并双侧中脑大脑脚、丘脑受累,1例左侧岛叶受累;1HMRS的谱线显示6例患者病变处可检出乳酸双峰,其中3例在脑脊液中检出乳酸峰。结论在MELAS型线粒体脑肌病中1HMRS可提供额外的直接反映疾病代谢异常的信息,有助于其诊断的确立,且具有替代传统有创检测脑脊液乳酸水平方法的潜能。     

乳酸酸中毒和卒中样发作综合征型线粒体脑肌病误诊分析

目的探讨乳酸酸中毒和卒中样发作综合征(MELAS)型线粒体脑肌病的临床特点及误诊原因。方法回顾性分析MELAS型线粒体脑肌病长期误诊1例的临床资料。结果本例因反应迟钝、发热3 d入院,行颅脑MRI及腰椎穿刺脑脊液等检查多次误诊为病毒性脑炎,先后行抗病毒、糖皮质激素、丙种球蛋白等治疗2年余,症状反复。后经血乳酸升高、乳酸运动试验阳性、肌肉活检病理检查确诊为MELAS型线粒体脑肌病,予相应治疗后病情明显缓解。结论 MELAS型线粒体脑肌病临床表现复杂多样,易误诊为病毒性脑炎。对病情反复发作按病毒性脑炎治疗效果不佳者应高度可疑本病,及时行血乳酸、乳酸运动试验、肌电图及肌肉活检病理检查,以帮助确诊。     

成人MELAS型线粒体脑肌病误诊一例分析

目的 分析MELAS型线粒体脑肌病的临床特点及误诊原因.方法 回顾性分析1例MELAS型线粒体脑肌病的临床资料.结果 患者出现发作性抽搐,言语异常、视力下降,于当地医院误诊为脑梗死,转入首都医科大学宣武医院误诊为病毒性脑炎,后经磁共振波谱分析、及左侧肱二头肌活检诊断为MELAS型线粒体脑肌病.给予B族维生素、辅酶Q10治疗,病情缓解.结论 对于青年患者出现进行性加重的智力、听力、视力下降及肌无力癫痫发作等症状,应考虑MELAS型线粒体脑肌病的可能,进一步结合血乳酸测定、肌肉活检病理及基因检查,以及早确诊.     

MELAS型线粒体脑肌病的多模态MRI诊断

目的：探讨MELAS型线粒体脑肌病的多模态影像学特点.方法：对11例MELAS型线粒体脑肌病患者的脑MRI、MRA、DWI及MRS影像资料进行分析.结果：MRI：MELAS病灶多位于枕顶叶大脑皮层,多发为主,多变性、游走性,与血管的走行不一致,5例海马、海马旁回受累,5例合并基底节核团受累,4例合并大脑和（或）小脑萎缩,7例增强扫描未见强化;MRA：1例病灶处动脉分支增多,6例未见异常;DWI：5例均为高和（或）稍高信号,ADC图为稍高信号2例、稍低信号2例、稍高等稍低混杂信号1例;MRS：病灶区及对侧正常区均可见升高的乳酸（Lac）双峰,病灶区与对侧正常区比较Lac及Lac/Cr均明显增高（P＜0.001）.结论：MELAS型线粒体脑肌病的多模态MRI表现有一定特异性,综合分析,可提示诊断.     

癫痫的病因诊断--附一例线粒体病基因诊断及分析

目的：分析线粒体病患者癫痫的特点及治疗。方法：报道1例反复癫痫发作并最终确诊为线粒体病患 者的临床资料,结合文献进行回顾性分析。结果：患者青少年期出现癫痫症状,部分性癫痫症状及全面广泛 强直性发作均在病程中有所体现,多联抗癫痫药物控制不佳,外周血基因检测示 mtDNA A3243G 突变 （44.7%）,诊断线粒体脑肌病伴乳酸血症和卒中样发作（MELAS）明确。入院后予减轻线粒体负担,改善细 胞功能及多联抗癫痫治疗后症状好转。结合既往国内外文献,进一步分析线粒体病癫痫的机制,发作形式 及治疗原则。结论：癫痫是线粒体疾病常见的临床症状之一,需采取综合治疗。     

毛球线粒体DNA的检测及临床应用研究

目的比较肌肉、血液和毛球线粒体DNA(mtDNA)的异质性多态水平，探讨毛球在线粒体相关疾病基因分析中的应用价值。方法收集50名无血缘关系汉族个体的肌肉、血液和毛发标本，采用聚合酶链反应(PCR)扩增mtDNA的高变区Ⅰ(HVⅠ)16033—16368bp片段并测序，比较3种不同组织的异质性多态水平。同时采用PCR-限制性长度多态性(RFLP)检测3例线粒体脑肌病合并乳酸血症及卒中发作综合征(MELAS)患者的mtDNA tRNA^leu基因nt．3243(A→G)突变，比较不同组织的突变检测率。结果肌肉标本异质性检测率为18％(9／50)，毛球为16％(8／50)，两者较接近，但均明显高于血液的10％检测率(5／50)。3例MELAS患者的肌肉和毛球标本均检出A3243G突变，仅两例患者的血液标本中检出此突变。结论毛球mtDNA的异质性多态水平接近肌肉，高于血液；毛球标本的线粒体点突变检测率高于血液，因此在线粒体相关疾病的基因分析中具有较高的临床应用价值。     

温故知新：老病历中的线粒体脑肌病伴乳酸血症和卒中样发作

线粒体脑肌病伴乳酸血症和卒中样发作（mitochondrial encephalomyopathy with lactic acidosis and stroke-like episodes, MELAS）是一组少见的由线粒体结构和（或）功能异常所导致的以脑和肌肉受累为主的多系统疾病.患者多于10~40岁发病,临床主要表现为运动不耐受、卒中样发作、癫痫、认知功能障碍、高乳酸血症,肌肉活检可见不整红边纤维（ragged red fibers,RRF）.     

A case of MELAS syndrome with typical cluster headache attacks: is it a causel or coincidental association?

Many findings relate migraine and cluster headaches to a genetic alteration, even if the site of the defect has not been identified. Some of these findings indicate an involvement of mitochondrial DNA, although some contrasting results have been reported. We describe a case of cluster headache occuring in a patient with MELAS syndrome. The diagnosis of MELAS was supported by the familiar anamnesis (the mother suffered from a similar form), by the laboratory reports (lacto-acidosis), by instrumental analysis (signs of encephalopathy on magnetic resonance imaging) and by biopsy findings (myopathy). The diagnosis was confirmed when a point mutation (Leu mutation at position 3423 of mitochondrial RNA) was found in the mitochondrial gene. The recurrent periods, characterized by attacks of unilateral pain and accompanied by homolateral symptoms (e. g. tearing, palpebral ptosis, rhinorrea), did not leave any doubt as to the diagnosis of cluster headache. We discuss whether the co-existence of MELAS and cluster headache was coincidental or causal. Received: 7 June 2001 / Accepted in revised form: 4 December 2001     

酷似免疫性脑炎的线粒体脑肌病伴乳酸酸中毒及卒中样发作综合征的诊断学特征

目的探讨酷似免疫性脑炎的线粒体脑肌病伴乳酸酸中毒及卒中样发作(MELAS)综合征的临床、神经电生理及影像学改变的诊断学特征,总结诊疗过程。 方法回顾性分析1例酷似免疫性脑炎的MELAS综合征的发病过程及临床资料,并复习相关文献。 结果患儿曾以发热、头痛、恶心、呕吐、视物模糊、眼球阵挛、步态不稳等相似症状分别于3,6个月前误诊为病毒性脑炎、免疫性脑炎两次住院,经治疗症状逐渐好转出院。现以相同症状加重并出现视物不清、行走困难再次入院。检查脑脊液常规及抗N-甲基-D-天冬氨酸受体(NMDA-R)抗体阴性,脑电图显示右侧枕部、后颞部大量散发－阵发性棘波/棘慢复合波、尖波/尖慢复合波,可波及右侧顶部;头颅磁共振(MRI)表现多样,可累及皮质和髓质,以灰质为主,表现为脑回明显肿胀,脑沟变窄、变浅,DWI呈弥散受限高信号,晚期脑组织可出现局部软化、脑萎缩改变,病灶可反复出现,基因检测A3243G位点突变,最终确诊为MELAS综合征。 结论临床症状酷似免疫性脑炎的患儿,遇有病情不稳、症状反复出现,应做进一步检查,排除或确诊是否为MELAS综合征。     

线粒体脑肌病伴高乳酸血症和卒中样发作误诊为脑梗死

目的探讨线粒体脑肌病伴高乳酸血症和卒中样发作的诊断要点、误诊原因及防范措施。方法对我院近期收治的误诊为脑梗死的线粒体脑肌病伴高乳酸血症和卒中样发作1例的临床资料进行回顾性分析。结果患者因双眼突发视力减退1 d入院,经查体及头颅MRI等相关检查考虑脑梗死,予相应治疗,视力稍好转。后患者行头颅数字减影血管造影及磁共振波谱检查排除脑梗死,最终经基因检查确诊线粒体脑肌病(MELAS综合征)。予改善代谢及脑供血等治疗3个月,患者病情明显好转,头颅MRI检查示病灶消失。结论临床表现与急性脑梗死相似、头颅MRI检查提示脑梗死及接诊医生知识面狭窄是导致本例误诊的主要原因。加强学习、拓宽知识面、了解并掌握线粒体脑肌病相关知识,可防止或减少其误诊。     

误诊为干燥综合征的Gitelman综合征一例

该文报道1例38岁女性患者,反复低钾血症伴碱性尿、尿钾升高,多次查抗核抗体及抗干燥综合征A（SSA）抗体阳性,外院曾疑诊为干燥综合征合并Ⅰ型远端肾小管酸中毒。但患者无明显口干、眼干表现,进一步检查非刺激唾液流率、角膜荧光染色、Schirmer泪液分泌试验及唇腺活组织检查结果均为阴性,故不支持干燥综合征的诊断;患者的代谢...     

MELAS型线粒体脑肌病的MRI诊断

目的 探讨MELAS型线粒体脑肌病的MRI的表现特点.方法 回顾分析10例经病理证实的MELAS型线粒体脑肌病患者的临床及MRI检查资料.结果 10例患者均为多脑叶发病,5例双侧颞、枕、顶叶皮层及皮层下可见大片状长T1长T2信号影,具有一定对称性,3例右侧额叶、颞叶、枕叶大片状长T1长T2信号影,2例左侧颞叶、枕叶大片状长T1长T2信号影,病变不按血管支配区分布.FLAIR序列呈高信号,急性期病变于DW1序列呈高信号,有3例累及脑深部核团,累及豆状核2例,累及豆状核和尾状核1例,累及小脑2例,累及脑干1例,并有不同程度脑萎缩4例.增强扫描少有强化.结论 MELAS型线粒体脑肌病的MRI表现有一定特征性,但最终诊断需结合临床表现和实验室检查.     

Adult-onset mitochondrial encephalopathy in association with the MT-ND3 T10158C mutation exhibits unique characteristics: A case report

BACKGROUND Mitochondrial diseases are a heterogenous group of multisystemic disorders caused by genetic mutations affecting mitochondrial oxidation function. Brain involvement is commonly found in most cases but rarely as the unique clinical manifestation. Since the knowledge of its clinical manifestation combined with genetic testing is important for preventing misdiagnosis and delay in treatment,we report here how we diagnosed and managed a very unusual case of mitochondrial encephalopathy.CASE SUMMARY We report a 52-year-old woman with recurrent stroke-like episodes carrying the m.10158 T>C mutation in the MT-ND3 gene, which is also responsible for fatal infant-onset Leigh syndrome. Despite the common mutation, the present case featured a distinct clinical and neuroimaging manifestation from Leigh syndrome. This patient presented with sudden onset of right-sided hemiparesis and hemilateral sensory disturbance accompanied by a left temporal cluster-like headache and later developed epilepsy during hospitalization, with no other signs suggestive of myopathy, lactate acidosis, or other systemic symptoms. Brain magnetic resonance imaging revealed variable lesions involving multiple cortical and subcortical regions. Furthermore, a negative genetic test obtained from peripheral blood delayed the diagnosis of mitochondrial disease, which was eventually established through second-generation DNA sequencing using biopsied muscle.CONCLUSION Based on this report, we suggest that clinicians pursue proper genetic testing for patients when the clinical phenotype is suggestive of mitochondrial diseases.     

Adult-onset of Mitochondrial Myopathy,Encephalopathy, Lactic Acidosis,and Stroke-Like Episodes (MELAS) Syndrome Presenting as Acute Meningoencephalitis: A Case Report

Background: Mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes (MELAS) syndrome is a rare mitochondrial disorder with a wide range of multisystemic symptoms. Epileptic seizures are common features of both MELAS and meningoencephalitis and are typically treated with anticonvulsants. Objectives: To provide the reader with a better understanding of MELAS and the adverse effects of valproic acid. Case Report: A 47-year-old man with a history of diabetes, hearing loss, sinusitis, and otitis media was brought to our emergency department due to acute onset of fever, headache, generalized seizure, and agitation. Because acute meningoencephalitis was suspected, the patient was treated with antibiotics on an empirical basis. The seizure activity was aggravated by valproic acid and abated after its discontinuation. MELAS was suspected and the diagnosis was confirmed by the presence of a nucleotide 3243 A→G mutation in the mitochondrial DNA. Conclusion: Detailed history-taking and systematic review help emergency physicians differentiate MELAS from meningoencephalitis in patients with the common presentation of epileptic seizures. Use of valproic acid to treat epilepsy in patients suspected of having mitochondrial disease should be avoided. Underlying mitochondrial disease should be suspected if seizure activity worsens with valproic acid therapy.