高通量测序技术检测肥厚型心肌病致病基因研究

目的:利用高通量测序技术对肥厚型心肌病(HCM)患者进行基因筛查,并与临床表型相对照,以期对临床诊治HCM提供参考依据。方法:对19例门诊HCM患者进行高通量测序,检测其突变类型并收集临床资料。结果:19例患者中有9例发现基因突变,除2例患者为单磷酸腺苷(AMP)激活蛋白激酶γ2调节亚基(PRKAG2)突变外,大部分基因突变为肌节蛋白基因突变。此外,检测出2例双基因突变患者,涉及PRKAG2与肌球蛋白结合蛋白C(MYBPC3)、MYBPC3与β-重链肌球蛋白(MYH7)双基因突变。基因突变的检出率为47%。MYH7基因突变患者发病年龄相对较轻,心肌肥厚程度较重,2例PRKAG2基因突变患者均有不同程度的心肌肥厚和传导阻滞的表现。结论:高通量测序技术准确、高效,对于HCM致病基因的检测阳性率高,与临床表型相对照,对于HCM的发生、发展以及转归提供了有利的依据。     

心脏型肌球蛋白结合蛋白C基因IVS15-1G＞A突变导致肥厚型心肌病

目的研究中国人肥厚型心肌病（HCM）致病基因,分析基因型与临床表型的关系。方法在一HCM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8例有血缘关系的研究对象中6例携带MYBPC3（gi：Y10129）G8887A突变,正常对照同一位置未见异常。该突变位点是MYBPC3基因15内含子的剪接位点的受体位点（IVS15-1G〉A）,其中3例携带者发病,表现为轻微的胸闷、胸痛和不对称性室间隔轻度肥厚（13～14mm）,发病较晚（48～75岁）。MYH7基因未发现突变。结论MYBPC3基因IVS15—1G〉A突变是该HCM家系的致病突变,其携带者临床表型较好。对于症状轻微、发病较晚的HCM患者,首选MYBPC3基因进行突变筛查是较为合理可行的方法。     

肥厚型心肌病患者肌球蛋白结合蛋白C基因筛查及其相应的临床特征

目的 研究国人肥厚型心肌病(HCM)患者的致病基因一肌球蛋白结合蛋白C基因(myosin binding protein C gene,MYBPC3)的突变位点,分析基因突变类型与临床表型的相互关系.方法对66例HCM患者的MYBPC3基因进行扫描,聚合酶链反应扩增其外显子及剪接部位的基因组DNA片段,直接测序分析.分析各突变患者相应的临床表型特点.结果经测序分析,发现Lys30lfs移码突变、Asp463stop无义突变、Gly523Arg错义突变和Tyr847His错义突变.MYBPC3导致的HCM为3例,占病例总数的4.5%.其临床表型各异,患者H30(Lys301fs)47岁发病,活动后胸闷、气短,超声显示室间隔肥厚达18.7 mm,左心室后壁14.7 mm.患者H48(Asp463stop)为25岁男性,24岁发病,室问隔肥厚达15.4 mm.患者H53(Gly523Arg和Tyr847His)发病年龄36岁,活动后胸闷、憋气,伴心前区疼痛,室间隔肥厚达27 min.结论 MYBPC3突变为HCM主要致病原因之一.MYBPC3突变基因携带者临床表型差异大.国人MYBPC3突变患者多在青壮年期发病,不同于国外报道的多发病较晚.     

心脏型肌钙蛋白Ⅰ基因4693 C/T突变导致家族性心尖部肥厚型心肌病

目的 研究中国人肥厚型心肌病(HCM)致病基因,分析基因型与临床表型的关系.方法 在一HCM家系中进行心脏型肌钙蛋白Ⅰ基因(TNNI3)、心脏型肌钙蛋白T基因(TNNT2)、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 在该家系接受家系调查的8例有亲缘关系的对象中5例携带TNNI3 4693C/T(R145W)突变,全部发病,外显率100%.正常对照组同一位置未见异常,该突变位点使TNNI3基因第7号外显子143位的精氨酸变为色氨酸,5例患者中4例表现为心尖部肥厚为主,1例表现为室间隔基底段肥厚为主,临床症状表现为轻微的胸闷.MYH7、MYBPC3及TNNT2基因未发现突变.结论 TNNI3基因4693C/T突变是该HCM家系的致病突变,其外显率为100%.其携带者主要表现为心尖部肥厚为主,临床表型较好.对于心尖部肥厚为主的HCM家系有必要进行TNNI3的突变筛查.     

“良性”MYH7基因Val606Met突变导致恶性肥厚型心肌病

目的研究汉族人群家族性肥厚型心肌病的致病基因突变位点,分析基因型与临床表型的关系。方法采集1个家族性肥厚型心肌病(HCM)家系成员的血液样本,并收集临床表型资料;对该家系先证者的28个HCM相关致病基因利用高通量测序进行靶向重测序;利用Sanger测序在家系成员中检测发现的致病突变位点;分析致病突变携带者的临床表型特点。结果高通量测序和Sanger测序发现并证实先证者携带β肌球蛋白重链基因(MYH7)Val606Met杂合错义突变,该突变在307名正常对照未检出;其他27个HCM相关致病基因中,未检出致病突变。家系遗传筛查发现3例HCM患者均携带MYH7基因Val606Met错义突变,该突变与HCM共分离。该家系3例HCM患者伴有心悸、胸痛、黑矇、晕厥等症状,先证者已经出现严重的心力衰竭,接受心脏移植后上述症状消失,生活质量明显改善。该家系另有2名成员在调查前发生心源性猝死。结论虽然有报道MYH7基因Val606Met错义突变为良性突变,但在本研究家系中,易导致早发心衰和猝死。因突变引起的终末期心衰接受心脏移植可能为最佳的治疗手段。     

MYBPC3基因G12101A和MYH7基因G15391A突变与肥厚型心肌病临床表型

目的 研究中国人家族性肥厚型心肌病(HCM)的致病基因突变位点,分析基因型与临床表型的相互关系.方法 在2个中国汉族HCM家系中进行心脏肌钙蛋白T基因(TNNT2)、心脏肌球蛋白结合蛋白C基因(MYBPC3)和心脏β-肌球蛋白重链基因(MYH7)的突变筛查,聚合酶链式反应(PCR)扩增基因功能区外显子片段并对PCR产物进行测序分析.结果 在ZZJ家系接受调查的8名成员中有4名成员携带MYBPC3基因G12101A杂合突变,该突变位点位于MYBPC3基因的21号外显子并使668位的精氨酸(R)转换为组氨酸(H),携带该突变的家族成员发病年龄较晚且均无梗阻及晕厥史.在FHL家系接受调查的6名成员中有3名成员携带MYH7基因G15391A杂合突变,该突变位点位于MYH7基因的23号外显子并使930位的谷氨酸(E)转换为赖氨酸(K),该突变导致的临床表型呈现发病年龄早、梗阻率高以及外显率高的特点.两家系成员TNNT2基因未发现突变,且正常对照组相同位置未发现异常.结论 MYBPC3基凶和MYH7基因是我国家族性HCM的致病基因,MYBPC3基因G12101A突变所致HCM临床症状相对较轻,而MYH7基因G15391A突变所致HCM临床症状出现早、进展较快且预后较差,是一种恶性突变.     

MYH7基因Glu931del突变导致恶性肥厚型心肌病

目的 本研究拟查明1个中国汉族肥厚型心肌病（HCM）家系的致病突变,并探讨基因型-表型关联。方法 利用二代测序技术,全面筛查家系先证者的28个HCM相关致病基因。通过Sanger测序,在家系中验证和筛查发现的可能致病突变,并对突变携带者进行表型分析。结果 二代测序发现先证者携带MYH7基因Glu931del杂合突变。家系筛查发现4名患者均携带该突变,突变与疾病共分离,该突变为此HCM家系的致病突变,常染色体显性遗传。Glu931del突变位于MYH7基因第23外显子,三个核苷酸缺失（c.2791_2793del GAG）,导致其所编码的心脏β-肌球蛋白重链的第931位谷氨酸缺失。MYH7基因第931位谷氨酸残基在不同物种间高度保守。临床表型分析发现,家系中4例患者的左心室最厚厚度在19mm-30mm之间,静息状态均无明显左室流出道梗阻,表现为胸痛、心悸和呼吸困难,并伴黑曚或有晕厥史。该家系另有两例患者在家系筛查前发生猝死,确诊年龄分别为5岁和6岁,死亡年龄均为16岁。该家系随访12年,HCM临床症状进展较快,1例患者左心室最大厚度由7mm发展为30mm,两例患者心功能进展为NYHA分级Ⅲ/Ⅳ级。结论 MYH7基因Glu931del突变导致的HCM表型较严重,易发生猝死和心衰,但也存在较大的表型异质性。二代高通量测序可以用于HCM致病基因的全面筛查。     

TNNI3基因Arg186Gln突变与家族性肥厚型心肌病的相关性分析

目的:研究中国汉族人群家族性肥厚型心肌病(HCM)常见致病基因突变位点,并对基因型与临床表型关系进行分析。方法:利用靶向外显子捕获测序方法对9例家族性HCM家系先证者进行MYH7、MYBPC3、TNNT2及TNNI3基因全外显子扩增和高通量测序,使用Sanger测序法在家系内进行验证。对阳性结果患者进行家系调查研究,调查资料包括一般临床症状、心电图、超声心动图以及3.0T心脏磁共振。进行门诊或电话定期随访,随访时间为1年或至患者死亡。结果:在其中1个家系中发现TNNI3基因第8号外显子Arg186Gln突变,该突变使遗传密码发生G→A转变,从而使其所编码的186位氨基酸由精氨酸(Arg)变为谷氨酰胺(Gln)。该家系中除先证者外还存在2例HCM患者,先证者为体检时发现心电图异常前来就诊,无临床症状,其父时有胸闷,在研究调查过程中猝死,其祖母胸闷气促症状明显。健康对照组中未发现上述基因突变。结论:家族性HCM患者TNNI3基因突变位点为Arg186Gln,携带该突变基因型的HCM患者呈现的临床表型不同,具有明显的临床异质性。     

心脏肌球蛋白结合蛋白C基因c.G772A突变与家族性肥厚型心肌病

目的:研究中国人肥厚型心肌病(HCM)患者致病基因突变位点,并分析基因型与临床表型的关系。方法:在HCM家系中利用靶向外显子捕获测序的方法对HCM先证者的30个与遗传性心肌病相关的基因进行全外显子扩增和高通量测序,进一步通过Sanger测序法在家系内及200例健康志愿者中进行验证。家系调查资料包括临床表现、体格检查、心电图及超声心动图。结果:该家系6例有血缘关系的研究对象中3例携带心脏型肌球蛋白结合蛋白C基因(MYBPC3)c.G772A杂合突变,该突变位点位于MYBPC3的258位的谷氨酸(E)变为赖氨酸(K)。其余家系成员未发现此突变。200例健康志愿者中未见异常。先证者及其女儿发病年龄晚且均伴有心悸、胸闷的症状,超声心动图示室间隔基底段增厚(16~18 mm)。先证者目前伴有阵发性室性心动过速恶性心律失常及心力衰竭,左心室流出道最大压差为56 mmHg(1 mmHg=0.133 kPa),属于猝死高危人群。结论:全面基因检测有利于临床危险分层及早诊治。MYBPC3的剪切位点突变c.G772A可能是该HCM家系的致病突变。     

肥厚型心肌病致病基因型与临床表现的关系及基因筛查在肥厚型心肌病筛查及疾病鉴别诊断中的作用

目的:分析肥厚型心肌病(HCM)致病基因型与临床表现的关系及基因筛查在HCM筛查及疾病鉴别诊断中的作用。方法:选择一个HCM家系共14人,多重靶向测序技术对先证者的26个已知最常见的HCM致病基因进行全外显子捕获测序,用Sanger测序对发现的突变进行验证并对其他家系成员及307名健康对照进行该突变位点的筛查,分析其基因型与临床表型的特点。结果:先证者及其子携带MYH7基因c.2146 GA(Gly716Arg)突变,该突变位于MYH7基因19号外显子,导致第716位氨基酸残基由Gly变为Arg,其他25个基因未发现突变。Sanger测序验证后对其他家系成员进行突变筛查,其他家庭成员及对照组未发现该突变,该突变与HCM在该家系中共分离。先证者携带的致病突变为从头突变,并遗传给其子。先证者临床表现为发病早(14岁)、劳力性呼吸困难、胸痛、心悸、心力衰竭,其子出生时即发现心肌肥厚。其父虽然室间隔肥厚(15 mm),但结合其年轻时曾为运动员的经历及遗传筛查的阴性结果,可基本排除其为HCM患者,考虑为生理性肥厚。结论:该家系HCM由MYH7基因从头突变p.Gly716Arg导致,该突变临床发病早,症状较重,预后较差,为恶性突变。基因筛查在HCM家系筛查及疾病鉴别诊断中有重要意义。     

Comprehensive analysis of the beta-myosin heavy chain gene in 389 unrelated patients with hypertrophic cardiomyopathy

OBJECTIVES: We sought to determine the prevalence and phenotype of beta-myosin heavy chain gene MYH7 mutations in a large cohort of unrelated patients with hypertrophic cardiomyopathy (HCM). BACKGROUND: Hypertrophic cardiomyopathy is a heterogeneous cardiac disease. MYH7 mutations are one of the most common genetic causes of HCM and have been associated with severe hypertrophy, young age of diagnosis, and high risk of sudden cardiac death. However, these clinical findings from large, family studies have not been confirmed in a large unrelated cohort. METHODS: Deoxyribonucleic (DNA) samples obtained from 389 HCM outpatients seen at this tertiary referral center were analyzed for mutations, using polymerase chain reaction, denaturing high-performance liquid chromatography, and DNA sequencing for all 38 protein-coding exons of MYH7. Clinical data were extracted from patient records blinded to patient genotype. RESULTS: Fifty-eight patients (15%) harbored 40 different mutations in MYH7. Compared with HCM patients without MYH7 mutations, HCM patients with MYH7 were younger at diagnosis (32.9 vs. 42.7 years, p = 0.0002), had more hypertrophy (left ventricular wall thickness of 24.2 vs. 21.1 mm, p = 0.0009), and more frequently underwent myectomy (60% vs. 38%, p = 0.002). The HCM patients with MYH7 mutations more often had a family history of HCM (43% vs. 29%, p = 0.006), but there was no difference in family history of sudden death (16% vs. 14%, p = NS). CONCLUSIONS: In this setting, HCM patients with MYH7 were diagnosed at a younger age and had more hypertrophy, but they had no greater frequency of sudden death among first-degree relatives. Although these associations may prove useful for targeted gene screening, caution should be exercised in terms of using pathogenic status in risk stratification.     

十个汉族家族性肥厚型心肌病MYH7、MYBPC3和TNNT2基因筛查结果及相应的临床特征

目的研究10个汉族家族性肥厚型心肌病的致病基因及突变特点,分析基因型与临床表型的相互关系。方法对10个无血缘关系的汉族家族性肥厚型心肌病的家系的MYH7基因、MYBPC3基因和TNNT2基因进行扫描,聚合酶链式反应扩增其外显子及剪接部位基因组DNA片段,直接测序分析,并分析各突变患者相应临床表型特点。结果10个汉族家族性肥厚型心肌病的家系中5个家系发现上述基因突变,3个家系MYH7基因发生错义突变,分别为Arg663His、Glu924Lys和Ile736Thr,Glu924Lya在中国患者中首次发现。这3个家系中3例患者猝死;2个家系MYBPC3基因发生错义突变、剪接突变和移码突变,1个家系先证者为复合突变即18外显子错义突变ArgS02Trp及27外显子剪接突变即IVS27＋12C〉T,先证者之母携带错义突变,先证者之父携带剪接突变;在另一家系首次发现Gly347fa移码突变,该家系中1例猝死。10个家系中未发现TNNT2基因的功能区突变,但在内含子3中发现一个STR多态性即CTTCT5个碱基的插入／缺失,7个家系先证者发现D基因型。结论MYH7基因为中国汉族家族性肥厚型心肌病最常见致病基因,临床表现较重,猝死率较高。MYBPC3突变也较常见,症状较轻,发病较晚,但复合突变发病早、症状重。同一突变的临床表型存在异质性提示多因素参与了肥厚型心肌病的发生与发展。     

Worse prognosis with gene mutations of beta-myosin heavy chain than myosin-binding protein C in Chinese patients with hypertrophic cardiomyopathy

BACKGROUND: No data are available on survival analysis and longitudinal evolution of patients with gene mutations of beta-myosin heavy chain (MYH7) and myosin binding protein C (MYBPC3) in Chinese. HYPOTHESIS: To prospectively investigate whether different gene mutations confer distinct prognosis. METHODS: We performed a prospective study in 70 HCM patients and 46 genetically affected family members without HCM-phenotype with direct DNA sequencing of MYH7 and MYBPC3, clinical assessments, and 5.8 +/- 1.8 years follow-up. RESULTS: After follow-up, more surgical intervention (8/52 versus 0/18, p < 0.001), higher sudden death risk (7/52 versus 0/18, p < 0.001) and shorter life span were found in patients with MYH7 mutations than in patients with MYBPC3 mutations (45.1 +/- 14.0 versus 73.5 +/- 7.5 years, p = 0.03). Seven of the 27 mutation carriers of MYH7 had clinical presentations of HCM, but no carriers of MYBPC3 mutations developed to HCM during follow-up. Maximal wall thickness was thicker in the patients carrying mutations in the global region of MYH7 than in those carrying mutations in the rod region of MYH7 (21.5 +/- 6.6 versus 15 +/- 6.1 mm, p < 0.05) at baseline. More sudden death (7/41 versus 0/11) and left ventricular dysfunction (NYHA Class III approximately IV, 17/32 versus 1/10) were identified in patients with mutations in the global region of MYH7 than in patients with other mutations. CONCLUSIONS: MYH7 mutations, especially in the global region, cause malignant clinical phenotypes.     

β肌球蛋白重链及心脏型肌球蛋白结合蛋白C基因突变的肥厚型心肌病患者生存分析

目的探讨携带β肌球蛋白重链(MYH7)及心脏型肌球蛋白结合蛋白C(MYBPC3)基因突变的肥厚型心肌病患者的6年生存情况。方法对采用测序方法确定的携带MYH7及MYBPC3基因突变的70例肥厚型心肌病患者进行前瞻性的随访。结果平均随访时间为(5.8±1.8)年,期间共有14例患者死亡,其中MYH7突变患者10例(32.1%/1000人年,95%CI为12.5～51.5),MYBPC3突变患者4例(35.2%/1000人年,95%CI为13.9～68.9),两者比较差异无统计学意义(P>0.05)。7例携带MYH7突变的患者发生猝死,基因突变的部位均位于MYH7基因的头部;而携带MYBPC3突变的患者均未发生猝死,两者比较差异有统计学意义(P<0.01)。结论携带MYH7基因突变的肥厚型心肌病患者发病年龄和死亡年龄均较早,猝死发生率高。携带位于MYH7基因头部突变的肥厚型心肌病患者较杆部突变患者的左心室最大室壁厚度更厚,猝死发生率高,更容易发生心力衰竭。对肥厚型心肌病患者进行基因检查十分必要。     

Myosin binding protein C mutations and compound heterozygosity in hypertrophic cardiomyopathy

OBJECTIVES: We sought to determine the frequency and phenotype of mutations in myosin binding protein C (MYBPC3) in a large outpatient cohort of patients with hypertrophic cardiomyopathy (HCM) seen at our tertiary referral center. BACKGROUND: Mutations in MYBPC3 are one of the most frequent genetic causes of HCM and have been associated with variable onset of disease and prognosis. However, the frequency of mutations and associated clinical presentation have not been established in a large, unrelated cohort of patients. METHODS: Using deoxyribonucleic acid from 389 unrelated patients with HCM, each protein coding exon of MYBPC3 was analyzed for mutations by polymerase chain reaction, denaturing high-performance liquid chromatography, and direct deoxyribonucleic acid sequencing. Clinical data were extracted from patient records blinded to patient genotype. RESULTS: Of 389 patients with HCM, 71 (18%) had mutations in MYBPC3. In all, 46 mutations were identified, 33 of which were novel (72%). Patients with MYBPC3 mutations did not differ significantly from patients with thick filament-HCM, thin filament-HCM, or genotype-negative HCM with respect to age at diagnosis, degree of hypertrophy, incidence of myectomy, or family history of HCM or sudden death. Patients with multiple mutations (n = 10, 2.6%) had the most severe disease presentation. CONCLUSIONS: This study defines the frequency and associated phenotype for MYBPC3 and/or multiple mutations in HCM in the largest cohort to date. In this cohort, unrelated patients with MYBPC3-HCM virtually mimicked the phenotype of those with mutations in the beta-myosin heavy chain. Patients with multiple mutations had the most severe phenotype.     

Beta-myosin heavy-chain gene mutations in patients with hypertrophic cardiomyopathy

INTRODUCTION AND OBJECTIVES. To determine the frequency of mutations in the beta-myosin heavy-chain gene (MYH7) in a cohort of patients with hypertrophic cardiomyopathy (HCM) and their families, and to investigate correlations between genotype and phenotype. METHODS. Single-strand conformation polymorphism analysis and sequencing of fragments with abnormal MYH7 gene mobility were carried out in 128 consecutive index patients with HCM. The phenotypes of patients with and without mutations were compared and the phenotypes of identified families were recorded. RESULTS. A total of 11 mutations were found in 13 families (10%); 7/11 had been previously described. The I736T mutation was found in three families and the A797T in two. One patient had two mutations (i.e., I736T and R787H). Mutations were more frequent in patients with a family history of sudden death (31%) and in those with severe hypertrophy (39% had a thickness > or = 30 mm). Mutations were found in 29 of 42 members of the 13 families, including six family members (20%) who were healthy carriers and aged < or = 36 years. Sudden death had occurred in eight members of four families: four in two families with the I736T mutation, one in a family with A797T, one in a family with R870H, and two in a family with A901P. CONCLUSIONS. MYH7 mutations were present in 10% of our families. Mutations were more frequent in patients with a family history of sudden death and in those with severe hypertrophy. Most mutations had been described previously. Some appeared in several families. For some mutations, the correlation between genotype and phenotype was stable, while for others, there were marked differences between the phenotypes of the index patients and their relatives, suggesting the presence of additional genetic factors that have yet to be identified.