ND3基因10191T>C突变导致的线粒体呼吸链复合物Ⅰ缺陷

本文报道1例由于ND3基因突变导致线粒体呼吸链复合物 Ⅰ 缺陷的患儿。该患儿自6岁起出现眼睑下垂、无力、癫癎及运动倒退,呈进行性加重。血液乳酸、丙酮酸增高,脑MRI示双侧基底节对称性损害,符合Leigh综合征诊断。为明确病因,提取患儿和父母的外周血白细胞线粒体蛋白,进行氧化磷酸化酶复合物 Ⅰ～V活性测定,并提取DNA,分析编码线粒体呼吸链复合物 Ⅰ 的7个线粒体结构基因。结果显示患儿线粒体呼吸链复合物 Ⅰ 活性为33.1 nmol/min?毫克线粒体总蛋白（正常对照44.0±5.4 nmol/min?毫克线粒体总蛋白）,复合物 Ⅰ 与柠檬酸合酶活性比值为19.8%（正常对照48.1%±11.0%）,均降低。复合物 Ⅱ～V活性正常。患儿线粒体ND3基因10191T>C突变。其父母线粒体基因及呼吸链复合物酶活性正常。治疗后,现患者16岁,癫癎控制良好,双下肢痉挛性瘫痪,智力正常。通过外周血白细胞线粒体氧化磷酸化酶复合物活性测定及基因分析,本研究首次诊断了编码线粒体呼吸链复合物Ⅰ亚基的ND3基因10191T>C突变导致复合物Ⅰ缺陷,为Leigh综合征的发病原因提供依据。     

线粒体呼吸链复合物Ⅱ缺陷所致Leigh综合征

线粒体呼吸链复合物Ⅱ缺陷是较为少见的氧化磷酸化障碍性疾病。本文对1例单纯线粒体呼吸链复合物Ⅱ缺陷所致Leigh综合征患儿的诊疗进行回顾性分析。患儿,男,10个月,8个月时出现发热,热退后出现进行性全身无力、运动发育倒退和吞咽困难。血乳酸、丙酮酸增高,脑MRI显示双侧基底节对称性损害。对患儿进行了外周血白细胞线粒体氧化磷酸化酶复合物I-V活性测定和线粒体基因突变位点筛查分析。线粒体呼吸链复合物Ⅱ活性为21.9 nmol/min?mg线粒体总蛋白（正常对照47.3±5.3 nmol/min?mg线粒体总蛋白）,柠檬酸合酶活性为22.1%（正常对照50.9%±10.7%）,均显著降低。线粒体基因分析未发现异常。患儿确诊为线粒体呼吸链复合物Ⅱ缺陷所致Leigh综合征。经治疗患儿运动功能明显恢复。目前患儿22个月,病情稳定。     

线粒体呼吸链复合物Ⅱ缺陷与疾病

本文就近年关于线粒体呼吸链复合物Ⅱ的结构、功能及其缺陷的临床表型、诊断、治疗及分子遗传学研究方面的进展进行文献综述。线粒体呼吸链复合物Ⅱ亦称琥珀酸泛醌氧化还原酶,是线粒体呼吸链的重要组分之一,对细胞的氧化磷酸化起着关键作用。呼吸链复合物Ⅱ与氧化性应激密切相关,是细胞内毒性物质以及异常代谢产物的敏感靶标。复合物Ⅱ缺陷导致的线粒体病临床表现多样,以神经肌肉进行性损害为主要表现,少数表现为心肌病、发作性呕吐、溶血尿毒综合征等。诊断有赖于线粒体呼吸链酶复合物活性测定和基因分析。患者受累组织的呼吸链复合物Ⅱ活性降低。已发现SDHA基因与编码复合物Ⅱ组装因子的SDHAF1基因的突变可导致复合物Ⅱ缺陷。目前线粒体呼吸链复合物Ⅱ缺陷的治疗主要是以改善线粒体功能为主。     

线粒体呼吸链酶复合物V缺陷与线粒体病

线粒体呼吸链酶复合物V,也称为ATP合酶,是位于线粒体内膜上的大蛋白复合体,由2个功能性蛋白复合物F0及F1构成。复合物V是线粒体呼吸链的最后一个复合物,在线粒体中通过电化学梯度传递质子,以ADP、Pi及Mg2+为原料合成ATP,为细胞供能。大多数患者新生儿期发病,导致严重脑损害或多脏器损害,病死率很高。主要临床表现为神经肌肉病、心肌病、高乳酸血症及3 甲基戊烯二酸尿症等,因受累器官的不同导致显著的临床异质性。复合物V由16个亚基组成,由线粒体基因与核基因共同编码。迄今,国内外已报道了MT-ATP6、MT-ATP8、ATPAF2、TMEM70、ATP5E基因突变导致的复合物V缺陷。本文总结了线粒体呼吸链复合物V的结构及功能,并对复合物V缺陷的病理、临床表现、诊断、治疗及分子遗传学研究进展进行了综述。     

线粒体基因13513G>A突变导致呼吸链酶复合物I缺陷Leigh综合征

Leigh综合征是由于线粒体呼吸链能量代谢障碍所导致的遗传性疾病,呼吸链酶复合物I缺陷是导致Leigh综合征的常见原因之一。该研究通过线粒体基因13513G>A突变分析首次确诊了1例中国人Leigh综合征患者。患儿为第一胎,12岁时出现抽搐,13岁时先后出现双眼视力下降,13岁来院就诊左眼颞侧视野缺损,痉挛步态,血液乳酸、丙酮酸增高,腓肠肌活检肌纤维内脂滴轻度增多;心电图检查显示不完全右束支传导阻滞;脑MRI显示双侧基底节对称性损害,符合Leigh综合征诊断,合并继发性癫癎。经基因分析证实患者存在线粒体基因13513G>A突变,导致线粒体呼吸链酶复合物I活性下降。治疗以多种维生素为主,补充左旋肉碱、辅酶Q10,同时给予卡马西平、苯巴比妥、丙戊酸等抗癫癎治疗。现在患儿16岁,休学,智力无明显倒退,体力、体重显著减退。Leigh综合征病因复杂,临床表现多种多样,该患儿以抽搐起病,合并视力减退,经基因分析明确了病因,有助于相关家庭的遗传咨询 。［中国当代儿科杂志,2009,11（5）：333-336］     

Citrin缺陷导致的新生儿肝内胆汁淤积症内分泌代谢特征分析

目的探讨Citrin缺陷导致的新生儿肝内胆汁淤积症(NICCD)的内分泌代谢特征。方法对2009年11月至2011年5月在广州市妇女儿童医疗中心确诊的20例NICCD患儿进行常规实验室检查、内分泌实验室检查、血浆氨基酸分析和酰基肉碱分析。结果 NICCD患儿有肝功能异常、高胆红素血症、低蛋白血症、凝血酶原时间延长,血脂、血氨、血乳酸升高,血铜蓝蛋白、血糖降低;甲状腺功能基本正常,生长激素(GH)升高,类胰岛素生长因子(IGF-1)降低;血浆氨基酸谱示瓜氨酸、苏氨酸、蛋氨酸、精氨酸、酪氨酸、天冬酰胺、鸟氨酸和赖氨酸升高;血浆酰基肉碱谱示游离肉碱、短链酰基肉碱、长链酰基肉碱升高。结论 NICCD患儿具有高脂血症、高氨血症、高乳酸血症、低血糖、生长激素抵抗、特征性氨基酸谱、特征性酰基肉碱谱等内分泌代谢特征。     

Citrin缺陷致新生儿肝内胆汁淤积症的研究进展

Citrin缺陷病为SLC25A13基因突变所导致的遗传性代谢性疾病,随着分子生物学技术的快速发展,其基因突变谱持续扩大.Citrin缺陷所致新生儿肝内胆汁淤积症表现为患儿出生后不久出现多样性肝功能受损、生化指标异常等,该病发病机制尚未完全清楚,目前仍依靠基因检测确诊.该文从分子遗传学、发病机制、临床表现、多种诊断技术及防治等方面介绍该病的研究进展.     

Citrin缺陷导致的新生儿肝内胆汁淤积症30例

目的 探讨Citrin缺陷导致的新生儿肝内胆汁淤积症(NICCD)患儿的临床表现和实验室检查特点.方法 选取2008年1月-2009年12月就诊于深圳市儿童医院的30例黄疸患儿(结合胆红素及未结合胆红素均升高,以结合胆红素升高为主),经常规实验室检查,结合尿气相色谱质谱分析、基因检测诊断为NICCD.对确诊患儿的临床表现、常规实验室检查、尿异常代谢产物、基因检测等进行分析.结果 30例NICCD患儿中93%(28/30例)患儿γ-谷氨酰转肽酶升高、43%(13/30例)患儿ALT升高、80%(24/30例)患儿AST升高、57%(17/30例)患儿ALP升高,4例存在低清蛋白血症,20例部分活化的凝血酶原时间延长,70%(21/30例)的患儿并巨细胞病毒感染.23例有高氨血症,97%(29/30例)的患儿甲胎蛋白升高.尿气相色谱质谱(GC-MS)分析显示28例(93%)患儿半乳糖增高,1例丝氨酸/苏氨酸比例倒置,1例丙氨酸及苏氨酸升高,6例并4-羟基苯乳酸增高.确诊后给予去乳糖饮食,所有患儿治疗1周黄疸明显消退,血总胆红素降低50%以上.结论 以结合胆红素升高为主的黄疸患儿鉴别诊断应考虑到NICCD,确诊后应早期给予饮食干预;合并巨细胞病毒感染的病例较多见,需注意区分何种因素占主导地位,必要时联合更昔洛韦抗病毒治疗.     

Citrin 缺陷导致的新生儿肝内胆汁淤积症 SLC25A13 基因分析

目的：Citrin 缺陷导致的新生儿肝内胆汁淤积症（NICCD）是一种由SLC25A13基因突变引起的常染色体隐性遗传病,临床可表现为肝内胆汁淤积性黄疸、低出生体重、生长迟缓和低蛋白血症等。本研究通过DNA测序技术探讨中国NICCD患儿 SLC25A13 基因突变类型。方法：针对 SLC25A13 基因的 18 个外显子及其侧翼区碱基序列设计引物,应用 PCR 技术扩增目的片度。PCR 扩增、纯化后直接测序,确定其突变类型。IVS16ins3kb 突变则采用巢式 PCR 和 RT-PCR 进行检测。结果：发现7种SLC25A13基因突变类型,包括851del4、1638ins23、IVS16ins3kb、IVS6+5G>A、c.775C>T（p.Q259X)、c.1505C>T（p.P502L） 和 c.1311C>T（p.C437C）;并确认一种复合突变类型［1638ins23+IVS16ins3kb］。其中c.775C>T（p.Q259X）、c.1505C>T（p.P502L）和 c.1311C>T（p.C437C）为新发现的基因突变类型。在20例NICCD患儿中,6 例为 851del4 纯合突变,7 例为杂合突变,另有 7 例为单一突变类型的杂合子。突变类型以 851del4 为主,占所有突变类型64%;其次为 1638ins23、IVS16ins3kb 和 IVS6+5G>A（分别占15%、12% 和 6%）。结论：851del4突变在 NICCD 患儿中最为常见。     

从肝细胞基侧膜载体蛋白角度谈希特林缺陷导致的新生儿肝内胆汁淤积症

希特林缺陷导致的新生儿肝内胆汁淤积症(neonatal intrahepatic cholestasis caused by citrin deficiency,NICCD)是一种由SLC25A13基因突变,位于肝细胞线粒体内膜的希特林蛋白功能不足而形成的遗传代谢病.NICCD发病病理生理关键是肝细胞能量缺乏;除了胆小...     

Intractable secretory diarrhea in a Japanese boy with mitochondrial respiratory chain complex I deficiency

The etiology of secretory diarrhea in early life is often unclear. We report a Japanese boy who survived until 3 years of age, despite intractable diarrhea commencing soon after birth. The fecal sodium content was strikingly high (109 mmol/L [normal range, 27–35 mmol/L]) and the osmotic gap was decreased (15 mOsm/kg), consistent with the findings of congenital sodium diarrhea. We examined the mitochondrial respiratory chain function by blue native polyacrylamide gel electrophoresis (BN-PAGE) in-gel enzyme staining, BN-PAGE western blotting, respiratory chain enzyme activity assay, and immunohistochemistry. Liver respiratory chain complex (Co) I activity was undetectable, while other respiratory chain complex activities were increased (Co II, 138%; Co III, 153%; Co IV, 126% versus respective control activities). Liver BN-PAGE in-gel enzyme staining and western blotting showed an extremely weak complex I band, while immunohistochemistry showed extremely weak staining for the 30-kDa subunit of complex I, but normal staining for the 70-kDa subunit of complex II. The patient was, therefore, diagnosed with complex I deficiency. The overall complex I activity of the jejunum was substantially decreased (63% of the control activity). The immunohistochemistry displayed apparently decreased staining of the 30-kDa complex I subunit, together with a slightly enhanced staining of the 70-kDa complex II subunit in intestinal epithelial cells. These data imply that intestinal epithelial cells are also complex I-deficient in this patient. Complex I deficiency is a novel cause of secretory diarrhea and may act via disrupting the supply of adenosine triphosphate (ATP) needed for the maintenance of ion gradients across membranes.     

End-stage liver disease as the only consequence of a mitochondrial respiratory chain deficiency: no contra-indication for liver transplantation

The prerequisite for liver transplantation as a therapeutic option for inherited metabolic diseases should be that the enzyme defect, being responsible for the major clinical (hepatic and/or extra-hepatic) abnormalities, is localised in the liver. Furthermore, no adequate dietary or pharmacological treatment should be available or such treatment should have an unacceptable influence on the quality of life. We report an infant, who developed end-stage liver disease with persistent lactic acidaemia in his first months of life. Analysis of the mitochondrial respiratory chain in liver tissue revealed a combined partial complex I and IV deficiency. No extra-hepatic involvement could be demonstrated by careful screening for multiple organ involvement, including analysis of the mitochondrial respiratory chain in muscle tissue and cultured skin fibroblasts. The boy received a reduced size liver graft at the age of 8 months. He recovered successfully. Almost 5 years after transplantation he is in good clinical condition. No clinical or biochemical signs of any organ dysfunction have been demonstrated. The considerations on which basis it was decided that there was no contra-indication to perform liver transplantation in this patient are discussed. Conclusion The possibility of a mitochondrial respiratory chain deficiency should be considered in liver disease of unknown origin prior to liver transplantation. Liver transplantation is a therapeutic option in mitochondrial respiratory chain deficiency-based end-stage liver disease provided that extra-hepatic involvement is carefully excluded. Received: 12 October 1999 and in revised form: 26 January 2000 / Accepted: 26 January 2000     

线粒体MT-TE基因突变致可逆性婴幼儿呼吸链缺乏症1例并文献复习

目的探讨线粒体MT-TE基因突变致可逆性婴幼儿呼吸链缺乏症的临床表现及基因突变特点。方法回顾分析1例确诊为可逆性婴幼儿呼吸链缺乏症患儿的临床资料,并复习相关文献。结果男性患儿,2个月23天,入院时消瘦,呼吸急促,双肺可闻及痰鸣音及喘鸣音;肌力IV级,肌张力减弱。有一胞姐生后不久因重症肺炎去世。入院时肌酸激酶同工酶123 U/L,肌酸激酶890 U/L;血乳酸8.9 mmol/L;病原学检查均为阴性。头颅MRI无异常。入院后患儿持续高乳酸血症、肌酶异常升高,伴呼吸困难,放弃治疗后死亡。基因检查示线粒体MT-TE基因存在14674TC突变,来源于母亲。国外文献报道线粒体MT-TE 14674TC突变患儿早期临床表现与进展型线粒体病类似,呼吸肌无力、喂养困难,运动发育里程碑延迟,肌酶及乳酸升高。予补充能量,维持内环境稳定等治疗,约1岁左右逐渐好转。结论线粒体MT-TE基因突变致可逆性婴幼儿呼吸链缺乏症早期表现与进展型线粒体病类似,积极治疗预后良好。早期进行基因检测可明确预后,增强治疗的信心。     

Mitochondrial respiratory chain complex I deficiency causes intractable gastrointestinal symptoms

We report the case of a 13‐month‐old girl with frequent vomiting, intractable diarrhea, hyperlactatemia, and liver dysfunction. Although the symptoms were treatment resistant, enteral nutrition formula containing medium‐chain triglycerides reduced the weight loss, vomiting, and diarrhea. Immunostaining of mitochondrial respiratory chain (MRC) complexes of the colonic mucosa confirmed the diagnosis of MRC complex I deficiency. This case shows that this disease should be included in the differential diagnosis of hyperlactatemia and intractable, cryptogenic gastrointestinal symptoms. In addition, the mucosa of the affected gastrointestinal organ should be analyzed on immunostaining or electron microscopy for MRC complexes.     

Clinical presentations and laboratory investigations in respiratory chain deficiency

Respiratory chain deficiencies have long been regarded as neuromuscular diseases. In fact, oxidative phosphorylation, i.e., ATP synthesis by the respiratory chain not only occurs in the neuromuscular system, indeed, a number of nonneuromuscular organs and tissues are dependent upon mitochondrial energy supply. For this reason, a respiratory chain deficiency can theoretically give rise to any symptom, in any organ or tissue, at any age with any mode of inheritance, due to the twofold genetic origin of respiratory enzymes (nuclear DNA and mitochondrial DNA).     

Combined deficiencies of the pyruvate dehydrogenase complex and enzymes of the respiratory chain in mitochondrial myopathies

In six patients with mitochondrial (encephalo-) myopathy investigations of skeletal muscle revealed a defect of pyruvate dehydrogenase complex (PDHC) in combination with one or more respiratory chain complex deficiencies. A combination of defects of this kind has not been reported previously. Five of the six patients presented within the 1st year of life and had a severe clinical course. Intrafamilial variability of the clinical course in dizygotic twins both suffering from a cytochrome c oxidase deficiency and one of them also from a PDHC deficiency suggests an additional effect of PDHC deficiency on the clinical symptoms. Immunoblot studies of PDHC in five of the patients revealed no abnormalities in their subunit pattern, rendering a defect of mitochondrial protein import or assembly unlikely. The finding of a combined PDHC and respiratory chain deficiency has implications for the diagnostic approach, for therapy and genetic counselling. The exact pathogenetic mechanism of this combination of defects remains to be elucidated.