抗信号识别颗粒抗体肌病八例临床分析

目的 总结抗信号识别颗粒抗体肌病患者的临床和骨骼肌病理改变特点.方法 选择8例患者采取免疫印迹法测定血清肌炎抗体谱并进行肌肉活检,肌肉标本进行组织学、酶组织化学和免疫组织化学染色.免疫组织化学染色的第一抗体为鼠抗人CD8、CD20、CD68单克隆抗体,分别标记T细胞、B细胞和巨噬细胞,主要组织相容性复合体(MHC)-Ⅰ单克隆抗体标记肌纤维膜,CD31单克隆抗体标记毛细血管内皮细胞.结果 8例患者血清抗信号识别颗粒抗体均为强阳性,其中3例伴随Ro-52抗体阳性.8例患者骨骼肌出现肌纤维坏死、再生以及巨噬细胞浸润,2例患者伴随肌纤维肥大和间质增生,2例伴随少数T细胞浸润.存在部分MHC-Ⅰ阳性肌纤维,毛细血管密度正常.结论 抗信号识别颗粒抗体肌病以缓慢发病的肢体无力为主要表现,可伴肺部病变.肌纤维坏死、再生为其主要病理改变,可以类似肌营养不良改变.     

低肌病性皮肌炎的临床和肌肉病理特点六例分析

目的 了解低肌病性皮肌炎的临床表现和肌肉病理改变特点.方法 收集我院2008年1月至2010年6月行肌肉活检的62例皮肌炎患者,按照低肌病性皮肌炎的诊断标准筛选6例,其中4例患者肌电图呈肌源性损害.同时对6例患者进行肱二头肌活检,标本进行组织学、酶组织化学染色和免疫组织化学染色,后者的第一抗体分别为CD8、CD20和CD68鼠抗人单克隆抗体以及标记主要组织相容性复合物Ⅰ型抗原(MHC-Ⅰ)的鼠抗人单克隆抗体.结果 6例患者的肌纤维内脂肪滴均有轻至中度增多,肌束衣出现个别巨噬细胞浸润和B淋巴细胞浸润.3例患者出现个别小圆状萎缩肌纤维呈束周分布的特点,伴随个别肌纤维的坏死再生.所有患者束周分布的肌纤维膜存在MHC-Ⅰ深染,束周分布的肌间毛细血管非特异性酯酶深染.结论 部分低肌病性皮肌炎患者的骨骼肌病理改变类似经典皮肌炎,提示此病可能是单纯无肌病皮肌炎和经典皮肌炎的中间型.     

母系遗传性肌病和心肌病:与线粒体性DNA tRNA~(Leu(UUR))的关系

线粒体基因组不同位点的突变都会影响到线粒体转译自身基因的功能和导致线粒体DNA(mtDNA)依赖性呼吸链复合体的部分缺陷,它们与临床上不同的线粒体疾患相关。一种新的母系遗传性疾病,特征为成人肌病和心肌病并存,而无神经系统受累,存在于单一的大家系的成员中。在指令 t-RNA的mtRNA 基因中,一种异质性的新的突变已被鉴定。该家系可供研究的21例中,5例临床发病,10例无症状母系成员,6例正常父系成员。家系中所有母系成员无论有无发病均存在蓬毛状红纤维。父系成员肌肉活检标本     

风湿性多肌痛的骨骼肌病理改变特点

目的探讨风湿性多肌痛的临床和骨骼肌病理改变特点。方法13例老年和老年前期患者符合1979年Bird的风湿性多肌痛诊断标准，发病年龄49～78岁，平均60．3岁，主要临床表现为急性发病的四肢近端骨骼肌对称性持续性疼痛。其中5例伴37℃～38℃的低热，1例有轻微贫血，未发现颞浅动脉炎的改变。13例血沉均增快，其中10例血沉大于50mm／1h，8例C反应蛋白升高，1例正常，4例未查；9例行肌酶检查，其中2例轻度升高；7例行肌电图检查，2例可见肌源性损害，5例正常。对患者的肱二头肌进行活检，标本进行组织学染色和酶组织化学染色。结果13例患者均有Ⅱ型肌纤维的萎缩，8例肌纤维氧化酶活性出现虫蚀样改变，8例出现肌纤维内脂肪滴增多，3例可见个别不典型破碎样红肌纤维，2例小血管周围可见少量炎细胞浸润。患者经过激素治疗后症状迅速改善，血沉及C反应蛋白显著下降。结论本组患者的主要临床特点是出现对称性骨骼肌疼痛和血沉加快，多数患者存在C反应蛋白升高，而贫血和颞浅动脉炎发生率不高。骨骼肌常见病理改变为Ⅱ型肌纤维萎缩和虫蚀样氧化酶活性改变，肌纤维内脂肪滴增多和部分患者出现破碎样红肌纤维提示此病常伴随能量代谢异常。     

以心脏症状首发的青年高肌酸肌酶血症临床病理特点分析

目的:报道10例以心脏症状首发的骨骼肌疾病,讨论该类疾病临床及肌肉病理改变特点。方法:选取2010年1月至2016年5月,以心脏症状首发的骨骼肌疾病就诊的10例患者,总结患者心脏及骨骼肌受累的临床特点,经知情同意后对患者行肌肉活检,标本进行常规组织学、酶学及免疫组织化学染色,7例患者进行基因学检查。结果:10例患者分别诊断为:脂肪沉积症3例,糖原累积病1例,强直性肌营养不良1例,Becker肌营养不良1例,肌原纤维肌病1例,混合结缔组织病合并多发性肌炎1例,Danon病1例,特发性良性肌炎1例。结论:心脏症状及心源性猝死可为骨骼肌病的首发症状或主要症状,尤其是青年不明原因的高CK血症患者。阳性家族史、肌肉病理有空泡和异常物质沉积为猝死的危险因素。     

包涵体肌炎的临床和病理分析

目的探讨包涵体肌炎的临床和病理特点。方法分析20例包涵体肌炎患者的临床、骨骼肌活检组织化学染色及电镜病理特点。结果骨骼肌活检组织化学染色病理特点：肌周膜、肌内膜、血管周围炎性细胞浸润,肌纤维大小不等,散在变性、坏死和再生肌纤维,结缔组织增生,肌纤维内可见边缘空泡,空泡周边淀粉样物质沉积,可伴破碎红纤维、肌纤维类型或分布异常。电镜：肌原纤维结构紊乱,Z线排列不整或消失,肌浆包涵体内可见大量髓磷脂小体和吞噬空泡聚集,周边可见脂滴、糖原颗粒。结论包涵体肌炎临床诊断、鉴别诊断困难,骨骼肌活检病理分析是确诊本病的可靠标准。     

以心肌病为主要表现的线粒体肌病一家系

分析一个以心肌病为主要表现的中国人线粒体肌病家系的临床、病理及致病基因特点。该家系4代共有患者8例,先证者以双下肢水肿为首发表现,伴有胸闷、气喘及运动后肌肉酸痛无力,其余患者表现为运动耐力下降或运动后肌肉酸痛无力,其中2例伴胸闷、气喘;所有患者体形消瘦、精神运动发育正常。先证者头颅MRI正常,肌电图提示神经源性改变,肌肉病理可见破碎红纤维及坏死、再生和核内移肌纤维;全外显子测序未见与疾病相关的基因突变,线粒体基因2代测序发现先证者A3243G突变,1代测序证实该突变与家系内患者共分离。单纯线粒体肌病患者可以心肌病为主要表现,肌电图可呈神经源性改变;对不明原因的以心肌受累为主要表现的患者应考虑线粒体肌病可能,尽早行肌肉病理和基因检查明确诊断。     

糖原累积病Ⅳ型的临床和病理特点

目的 报道1例22岁男性糖原累积病Ⅳ型(Anderson disease)患者临床及病理特点.方法 对该患者行详细的病史询问和体格检查、心脏和腹部超声检查、头颅影像学、肌电图以及肌肉病理检查.结果患者儿童期发病,主要表现为四肢近端肌肉运动不耐受和疲劳感,偶有心悸;腹部超声示肝硬化、门脉高压和巨脾,超声心动图示心肌肥大、二尖瓣和三尖瓣轻度关闭不全;四肢骨骼肌肌电图示肌源性损害.头颅影像正常.肌肉病理HE染色示肌纤维内大量嗜碱性物质沉积,沉积物糖原染色(PAS)染色呈强阳性,淀粉酶处理后部分阳性物质被消化.电镜下嗜碱性沉积物为分支状细丝样结构以及无定型的颗粒样物质.结论 此例为国内首次报告的糖原累积病Ⅳ型,属于分支酶缺陷病,受累组织和器官以骨骼肌、肝脏、脾脏和心肌为主.     

他汀类药物相关肌病的临床和骨骼肌病理特点

目的 探讨他汀类药物相关肌病(简称他汀肌病)的临床特点及骨骼肌病理改变特点.方法 分析2012年4月至2014年10月就诊于北京大学第一医院并行肌肉活检的9例他汀肌病患者的临床及病理资料.结果 9例患者均口服他汀类药物4d至4年,就诊年龄55 ～74(63 ±6)岁,其中男6例,女3例.3例出现肌痛,6例出现四肢近端为主的肌无力,3例无任何临床症状.所有患者血清肌酸激酶(CK)升高(468 ～8 000 U/L).7例患者行血清肌炎抗体检查,均阴性.6例患者行肌电图检查,2例出现肌源性损害.6例患者行双侧大腿骨骼肌MRI检查,其中2例显示有部分肌群水肿及轻度脂肪化.骨骼肌活检病理主要表现:肌纤维萎缩、坏死、再生、脂肪滴增多,部分患者出现破碎蓝纤维、细胞色素c氧化酶阴性肌纤维及还原型辅酶Ⅰ四氮唑还原酶活性降低,主要组织相容性复合物-Ⅰ在肌纤维膜不同程度表达,补体C5b-9染色显示肌内衣、胞质以及毛细血管少量补体沉积.随访发现,多数(7例)患者停用他汀类药物或换用其他他汀类药物后,症状及CK水平改善,仅2例患者需应用免疫抑制治疗且有效.结论 本组患者中多数(7例)他汀肌病为自限性,停用他汀类药物后可自行好转,个别患者(2例)可出现免疫性坏死性肌肉病,需要应用免疫抑制治疗.     

心脏型肌球蛋白结合蛋白C基因13261 G＞A突变导致肥厚型心肌病的临床表型分析

目的研究中国人肥厚型心肌病致病基因,分析基因型与临床表型的关系。方法在一肥厚型心肌病家系中进行心脏型肌球蛋白结合蛋白C基因（MYBPC3）和β-肌球蛋白重链基因（MYH7）突变筛查,利用聚合酶链反应（PCR）扩增其功能区的外显子片段,双脱氧末段终止法测序。家系调查资料包括临床表现、体格检查、心脏超声和心电图。结果在该家系27例有血缘关系的研究对象中9例携带MYBPC3 13261 G〉A（G758D）突变,正常对照组同一位置未见异常。该突变位点是MYBPC3基因第23号外显子的甘氨酸突变为天冬氨酸,其中2例携带者发病,一例表现为心室扩大,左室射血分数减低等扩张型心肌病样表现,伴室间隔不对称肥厚,厚度为14mm,另外一例患者为典型的肥厚型心肌病表现。MYH7基因未发现突变。结论MYBPC3基因13261 G〉A突变是该肥厚型心肌病家系的致病突变,其外显率为22％,其中一例患者表现为肥厚型心肌病的扩张相,MYBPC3基因G758D突变可能是肥厚型心肌病进展为扩张型心肌病样改变的原因之一。对临床表现为扩张型心肌病的患者进行家族史调查及基因检查十分必要。     

Epidemiology of desmin and cardiac actin gene mutations in a european population of dilated cardiomyopathy.

AIMS: Although dilated cardiomyopathy is the most frequent form of cardiomyopathy, its aetiology is still poorly understood. In about 20-30% of cases the disease is familial with a large predominance of autosomal dominant transmission. Ten different chromosomal loci have been described for autosomal dominant forms of dilated cardiomyopathy. Only two genes have been associated with pure forms (without myopathy and/or conduction disorders) of the disease, the cardiac actin and the desmin genes. Our aim was to determine the proportion of dilated cardiomyopathy affected individuals carrying a mutation in one of these two genes. METHODS AND RESULTS: We performed (1) a systematic polymerase chain reaction-SSCP-sequencing screening of the coding sequences of cardiac actin on DNA samples from 43 probands of dilated cardiomyopathy families and 43 sporadic cases; (2) a systematic polymerase chain reaction-SSCP-sequencing screening of the coding sequences of desmin combined with a search for the described missense mutation (Ile451Met) by restriction fragment length polymorphism analysis on DNA samples from 41 probands of dilated cardiomyopathy families and 22 sporadic cases. CONCLUSION: None of the patients presents a mutation in any of these two genes. Consequently, the proportion of European dilated cardiomyopathy affected individuals bearing a mutation in (1) the cardiac actin gene is less than 1.2%, (2) the desmin gene is less than 1.6%.     

Restrictive Cardiomyopathy,Atrioventricular Block and Mild to Subclinical Myopathy in Patients With Desmin-Immunoreactive Material Deposits

Objectives. We present clinical data and heart and skeletal muscle biopsy findings from a series of patients with ultrastructural accumulations of granulofilamentous material identified as desmin.Background. Desmin cardiomyopathy is a poorly understood disease characterized by abnormal desmin deposits in cardiac and skeletal muscle.Methods. Clinical evaluation, endomyocardial and skeletal muscle biopsy, light and electron microscopy and immunohistochemistry were used to establish the presence of desmin cardiomyopathy.Results. Six hundred thirty-one patients with primary cardiomyopathy underwent endomyocardial biopsy (EMB). Ultrastructural accumulations of granulofilamentous material were found in 5 of 12 biopsy samples from patients with idiopathic restrictive cardiomyopathy and demonstrated specific immunoreactivity with anti-desmin antibodies by immunoelectron microscopy. Immunohistochemical findings on light microscopy were nonspecific because of a diffuse intracellular distribution of desmin. All five patients had atrioventricular (AV) block and mild or subclinical myopathy. Granulofilamentous material was present in skeletal muscle biopsy samples in all five patients, and unlike the heart biopsy samples, light microscopic immunohistochemical analysis demonstrated characteristic subsarcolemmal desmin deposits. Two patients were first-degree relatives (mother and son); another son with first-degree AV block but without myopathy or cardiomyopathy demonstrated similar light and ultrastructural findings in skeletal muscle. Electrophoretic studies demonstrated two isoforms of desmin—one of normal and another of lower molecular weight—in cardiac and skeletal muscle of the familial cases.Conclusions. Desmin cardiomyopathy must be considered in the differential diagnosis of restrictive cardiomyopathy, especially in patients with AV block and myopathy. Diagnosis depends on ultrastructural examination of EMB samples or light microscopic immunohistochemical studies of skeletal muscle biopsy samples. Familial desminopathy may manifest as subclinical disease and may be associated with abnormal isoforms of desmin.     

Dilated cardiomyopathy and the dystrophin gene: an illustrated review.

Cardiomyopathy is often found in patients with Duchenne and Becker muscular dystrophy, which are X linked muscle diseases caused by mutations in the dystrophin gene. Dystrophin defects present in many different ways and cases of mild Becker muscular dystrophy have been described in which cardiomyopathy was severe. Female carriers of Duchenne muscular dystrophy can develop symptomatic skeletal myopathy alone or combined with dilated cardiomyopathy. They can also develop dilated cardiomyopathy alone. X linked dilated cardiomyopathy has been found in association with dystrophin defects. The relation between the molecular defects and the cardiac phenotypes has not yet been established. New mutations in the dystrophin gene are common and such mutations cause one third of the cases with Duchenne and Becker muscular dystrophy. This means that sporadic cases of cardiomyopathy caused by dystrophin defects are likely. This paper reports such a case in a boy of 14 who died of dilated cardiomyopathy. Before the cardiac investigation, which was performed one month before he died, he had not complained of muscular weakness. He had minor signs of limb girdle myopathy and slightly increased concentrations of serum creatine kinase. He was found to have an unusual deletion in the dystrophin gene.     

Genetics of dilated cardiomyopathy

Dilated cardiomyopathy is one of the leading causes of heart failure and a primary cause for heart transplantation in patients below the age of 40 years. Despite major advances in diagnostic procedures such as examination of myocardial biopsies, the etiology remains unknown in many patients. Chronic inflammation or myocarditis and chronic alcohol abuse are considered two main etiologic factors in dilated cardiomyopathy. A third causal factor, namely genetic transmission of the disease, is at least as common as myocardial inflammation or toxic damage. Several prospective studies of relatives of patients with dilated cardiomyopathy proved that about 25-30% of all cases are of familial etiology. The most common mode of inheritance is autosomal dominant. Less frequently is the disease inherited as an X-chromosomal trait. Autosomal recessive and mitochondrial transmission is rare. The penetrance is highly variable and age dependent. Many relatives of patients with DCM show only minor cardiac abnormalities and it is unknown whether they progress to full cardiomyopathy in later life. Examination of families has identified so far eight disease genes, namely the dystrophin, tafazzin, cardiac actin, desmin, lamin A/C, delta- sarcoglycan, cardiac beta-myosin heavy chain, and cardiac troponin T gene. Certain mutations in lamin A/C cause conduction system disease and dilated cardiomyopathy, whereas other mutations cause in addition skeletal muscle myopathy. Dystrophin mutations are the cause of the rare X-linked dilated cardiomyopathy without skeletal muscle involvement and a progressive course in young men. Other mutations in the dystrophin gene, mainly deletions, are the cause of the muscular dystrophy Becker and Duchenne which also present with dilated cardiomyopathy. Mutations of the desmin, delta-sarcoglycan, the cardiac actin and beta-myosin heavy chain as well as the troponin T gene are known to cause autosomal dominant-dilated cardiomyopathy without other abnormalities. The infantile X-linked DCM is caused by mutations of the tafazzin gene. The onset of the disease is typically within the first year of life and death occurs usually in childhood. Most patients may in addition be characterized by skeletal myopathy, short stature, neutropenia and abnormal mitochondria, also referred to as Barth syndrome. Knowledge of the DCM disease genes led to the new hypothesis that dilated cardiomyopathy is a disease of the myocardial force generation or force transmission. Many more disease loci are known but the responsible disease genes are not yet identified. Better understanding of the expression and function of disease genes may eventually result in new diagnostic and therapeutic tools in order to improve the prognosis of this severe disorder.     

Frequency and clinical characteristics of dilated cardiomyopathy caused by desmin gene mutation in a Japanese population.

AIMS: Dilated cardiomyopathy is partly caused by a mutation of some cytoskeletal or nuclear envelope proteins. It has been confirmed recently that a missense mutation of the gene encoding desmin, a cytoskeletal protein, can cause dilated cardiomyopathy. This study was aimed at elucidating the frequency and clinical characteristics of dilated cardiomyopathy caused by desmin mutation. METHODS AND RESULTS: We examined 265 Japanese patients with dilated cardiomyopathy (217 sporadic cases and 48 probands of familial dilated cardiomyopathy). The exon 8 of the desmin gene, the critical region for the pathogenesis of dilated cardiomyopathy, was analysed by polymerase chain reaction, single-strand conformation polymorphism and sequencing. The same missense mutation (Ile451Met) as reported previously was detected in three patients (1.1%). All these patients were male and sporadic, and more likely to be accompanied by characteristics such as younger age at diagnosis, lower fractional shortening and ejection fraction than each mean value of sporadic cases. The chronological changes in cardiac function were inconsistent in the three patients. CONCLUSION: The missense mutation (Ile451Met) of the desmin gene can be the genetic cause of dilated cardiomyopathy, although with very low frequency. The ages at diagnosis were younger and the cardiac function had deteriorated further than general cases of sporadic dilated cardiomyopathy.     

Dilated cardiomyopathy in patients with mutations in anoctamin 5

Background

Homozygous mutations in ANO5, a gene encoding anoctamin 5, a putative calcium-activated chloride channel, have recently been reported in patients with adult-onset myopathies or isolated high-CK levels. Cardiomyopathy has not previously been reported in these populations despite a proven expression of anoctamin 5 in the cardiac muscle.

Methods

Patients presenting for the management of high-CK levels or overt myopathy with proven ANO5 mutations were prospectively investigated between June 2010 and March 2012 in Pitié Salpêtrière Hospital, according to a standardised protocol. Neurological and cardiological clinical examinations, CK assessment, electrocardiogram (ECG), and echocardiography were performed, as well as cardiac MRI and coronary CT angiography in patients with left ventricular (LV) dysfunction.

Results

Our study included 19 consecutive patients (male = 15, age = 46.2 ± 12.7 years) from 16 families. Five had asymptomatic high-CK levels and 14 had overt myopathy. One patient had a personal history of stable coronary artery disease with normal ventricular function. ECG showed ventricular premature beats in one patient. Echocardiography displayed LV dilatation in two patients, LV dysfunction in one, and both abnormalities in two who fulfilled criteria for dilated cardiomyopathy which was confirmed by cardiac MRI and normal CT angiography.

Conclusions

Dilated cardiomyopathy is a potential complication in patients with myopathies due to mutations in the ANO5 gene whose screening requires specific procedures.     

The absence of desmin leads to cardiomyocyte hypertrophy and cardiac dilation with compromised systolic function

Desmin is the muscle-specific member of the intermediate filament family of cytoskeletal proteins, expressed both in striated and smooth muscle tissues. In mature striated muscle fibers, the desmin filament lattice surrounds the Z-discs, interconnects them to each other and links the entire contractile apparatus to the sarcolemmal cytoskeleton, cytoplasmic organelles and the nucleus. There have been increasing reports of human cardiomyopathies associated with abnormal accumulation and aggregation of desmin filaments. Recently identified desmin mutations in humans suffering from skeletal muscle myopathy and cardiomyopathy suggest that these diseases might arise as a consequence of impaired function of desmin filaments. Previous generation of desmin null mice in our laboratory demonstrated that the absence of desmin results in myocyte ultrastructural defects and myocyte cell death leading to fibrosis and calcification of the myocardium. However, the effects that these defects have on cardiac function were not addressed. To further our understanding of desmin function in vivo, and in order to address the direct involvement of desmin in cardiomyopathy, we investigated the effect of the absence of desmin on myocardial mass, myocyte size and shape, changes in gene expression and cardiac systolic and diastolic function in mice. Morphometric characterization of isolated cardiomyocytes demonstrated a 24% increase in cell volume in the desmin null mice, solely due to an increase in transverse section area, suggesting for the first time that mice lacking the intermediate filament protein desmin develop concentric cardiomyocyte hypertrophy. This type of hypertrophy was accompanied by induction of embryonic gene expression and later by ventricular dilatation, and compromised systolic function. These results demonstrate that desmin is essential for normal cardiac function, and they suggest that the absence of an intact desmin filament system, rather than accumulation of the protein, may be responsible for the pathology seen in some of the desmin associated cardiomyopathies.     

Desmin accumulation restrictive cardiomyopathy and atrioventricular block associated with desmin gene defects

BACKGROUND: Primary desminopathies are caused by desmin gene [DES (MIM*125660)] mutations. The clinical spectrum includes pure myopathies, cardiomuscular diseases and cardiomyopathies. Patients with restrictive cardiomyopathy (RCM) plus atrioventricular block (AVB) due to DES defects are frequently unrecognized unless desmin accumulation is specifically investigated in endomyocardial biopsy (EMB) by ultrastructural study. AIMS: To describe a cardiological phenotype characterized by RCM plus AVB due to desmin accumulation caused by DES defects. METHODS AND RESULTS: Desmin accumulation was diagnosed by means of ultrastructural and immunocytochemical studies of EMB in four unrelated probands with RCM and AVB. Candidate genes [DES and alphaB-crystallin (CRYAB)] were screened using sequence analysis. Four DES gene mutations were identified: three new (R16C, T453I and a 10 bp deletion at the exon-intron boundary of exon 3 disrupting the donor splice site) and one known (R406W). The disease was autosomal dominant in two families, recessive in one and associated with a de novo mutation in one. The mutations cosegregated with phenotype in all patients. CRYAB gene screening was negative. CONCLUSIONS: A cardiac phenotype characterized by RCM and AVB caused by desmin accumulation is associated with DES mutations. Although the mutations affected different domains, the cardiac phenotype was identical.     

Familial dilated cardiomyopathy and isolated left ventricular noncompaction associated with lamin A/C gene mutations

LMNA mutations have been associated with familial or sporadic dilated cardiomyopathy (DC), with or without conduction system disease. We studied the LMNA gene in 67 consecutive patients with DC (18 had familial DC, 17 had possible familial DC, and 32 sporadic DC). From genomic DNA, coding regions of the LMNA gene were amplified by polymerase chain reaction, studied by single-strand conformation polymorphism, and cycle sequenced. Mutations were confirmed by restriction fragment length polymorphism. Two disease-causing mutations were found in families A and B. In family A, a novel R349L mutation was present in the mother and her identical twin daughters. They required cardiac transplantation at 36, 18, and 20 years of age. In family B, the R190W mutation was present in 2 cousins with DC and without conduction system disease (1 had cardiac transplantation at 45 years of age and 1 died suddenly at 46 years of age) and in 2 of their sons. The mothers of the 2 affected patients died due to cardiac causes in their 40s (1 died suddenly). One of the carriers fulfilled diagnostic criteria for isolated left ventricular noncompaction. Our data associated the R349L and R190W mutations in LMNA with severe forms of familial DC. LMNA mutations should be considered in the genetic screening of patients with familial DC without conduction system disease. Isolated left ventricular noncompaction may be part of the phenotypic spectrum of the laminopathies.     

家族性肥厚型心肌病MYH7基因突变的筛查与分析

目的 研究家族性肥厚型心肌病(hypertrophic cardiomyopathy,HCM)的主要致病基因β肌球蛋白重链(beta-myosin heavy chain gene,MYH7)突变,并分析基因型与表型的关系.方法 对3个HCM家系成员的MYH7基因3～23号外显子及附近上下游序列采用DHPLC及直接测序分析.结果 在其中一个家系中发现MYH7基因14号外显子中存在Thr441Met突变,该突变曾经在一莱恩远端肌病患者中发现,而在中国人中是首次发现.另外两个家系也发现有不同位点的突变.结论 MYH7基因在HCM家系中具有较高的突变率,不同突变基因型以及基因突变携带个体在临床表型上有所差异.采取基因突变检测和分析,有利于HCM家族成员的诊断、患病风险预测及疾病早期预防和治疗.

Abstract：

Objective To detect gene mutations on beta-myosin heavy chain gene MYH7 in 3 Chinese families with hypertrophic cardiomyopathy ( HCM), and to analyze the correlation between genotype and phenotype. Methods A denaturing high-performance liquid chromatography (DHPLC) and sequencing mutation screening of the exons ( exon3-23 ) coding for MYH7 gene were performed in 3 Chinese families with HCM. Results In this study, we identified several mutations in MYHT. A mutation of Thr441 Met previously reported in a patient with Laing distal myopathy was first identified in one Chinese pedigree. Conclusion This study illustrated the high frequency of mutation in MYH7 gene in Chinese HCM families. Different mutations and carriers of the MYH7 gene present phenotypic heterogeneity. Mutation screening and analysis in HCM family could therefore facilitate the early HCM diagnosis and would be helpful for the prediction, prevention and early treatment of HCM linked with MYH7 gene mutation.