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Objective: To analyze the relationship between genotype and clinical phenotype of the MYH7-R453C mutation in five Chinese hypertrophic cardiomyopathy (HCM) families. Methods: A retrospective cohort study was conducted on 527 unrelated HCM probands who were first diagnosed at the First Affiliated Hospital of Air Force Medical University (Xijing Hospital) from February 2014 to July 2018, and the high-throughput whole exome targeted sequencing of 96 genes related to hereditary cardiovascular disease was performed on the probands. The probands carrying the MYH7-R453C mutation were screened out, and their family members carrying the mutation were verified using Sanger sequencing. Healthy individuals without family history of genetic diseases from the same period and ethnicity were recruited as controls. Clinical data such as echocardiography, 12-lead electrocardiogram, and cardiac magnetic resonance imaging of the probands and their family members were collected, and the correlation between patient genotype and clinical phenotype was analyzed. Endpoint or key events were recorded through hospital re-examination or telephone follow-up. Results: The MYH7-R453C mutation was detected in 5 HCM probands, and clinical data and genetic results of 20 family members, including probands, were collected. Among them, 13 carried the MYH7-R453C mutation, of which 12 were diagnosed with HCM, and one child (F1Ⅲ 5 ) experienced early changes of HCM. The seven family members who did not carry the MYH7-R453C mutation had normal echocardiograms and 12-lead electrocardiograms. Among the 12 patients diagnosed with HCM, 2 experienced (F2Ⅱ 7 , F5Ⅰ 2 ) sudden cardiac death, 2 experienced (F1Ⅲ 1 , F3Ⅲ 3 ) events of sudden cardiac death survival, 2(F1Ⅱ 2 , F3Ⅱ 1 ) died from heart failure during the follow-up period. Combined with the initial visit and follow-up, 4 families (F1, F2, F3, F5) had a family history of sudden death, among which 3 families probands or multiple family members experiencing sudden death before the age of 30 and adverse outcomes such as implantation of implantable cardioverter-defibrillators after sudden death survival. Conclusions: In the five families with HCM carrying MYH7-R453C mutations, genotype is highly correlated with clinical phenotype, and patients have a high risk of sudden death and poor prognosis. Early diagnosis of individuals carrying the MYH7-R453C gene mutation, both within the patient's family and in the patients themselves, is crucial for initiating early treatment, preventing sudden death, and assessing prognosis.

Objectives: To investigate the clinical phenotype and genotype characteristics of children withcardiomyopathy (CM) associated with MYH7 gene mutation., Methods: A retrospective analysis was conducted on the medical data of five children with CM caused by MYH7 gene mutation who were diagnosed and treated in the Department of Cardiology, Hebei Children's Hospital., Results: Among the five children with CM, there were three girls and two boys, all of whom carried MYH7 gene mutation. Seven mutation sites were identified, among which five were not reported before. Among the five children, there were three children with hypertrophic cardiomyopathy, one child with dilated cardiomyopathy, and one child with noncompaction cardiomyopathy. The age ranged from 6 to 156 months at the initial diagnosis. At the initial diagnosis, two children had the manifestations of heart failure such as cough, shortness of breath, poor feeding, and cyanosis of lips, as well as delayed development; one child had palpitation, blackness, and syncope; one child had fever, runny nose, and abnormal liver function; all five children had a reduction in activity endurance. All five children received pharmacotherapy for improving cardiac function and survived after follow-up for 7-24 months., Conclusions: The age of onset varies in children with CM caused by MYH7 gene mutation, and most children lack specific clinical manifestations at the initial diagnosis and may have the phenotype of hypertrophic cardiomyopathy, dilated cardiomyopathy or noncompaction cardiomyopathy. The children receiving early genetic diagnosis and pharmacological intervention result in a favorable short-term prognosis.

Objective: To explore the clinical and genetic characteristics of eight children with Primary hypertrophic cardiomyopathy (HCM)., Methods: Eight children with HCM admitted to the Department of Cardiology of Henan Children's Hospital from January 2018 to December 2021 were selected as the study subjects. Clinical data of the children were collected. Whole exome sequencing was carried out on two children, and trio whole exome sequencing was carried out on the remainder 6 children. Sanger sequencing was used to verify the candidate variants in the children and their parents, and the pathogenicity of the variants was evaluated based on the guidelines from the American College of Medical Genetics and Genomics (ACMG)., Results: The patients had included 5 males and 3 females, with their ages ranging from 5 to 13 years old. The average age of diagnosis was (7.87 ± 4.8) years old, and the cardiac phenotype showed non-obstructive HCM in all of the patients. WES has identified variants of the MYH7 gene in 4 children, including c.2155C>T (p.Arg719Trp), c.1208G>A (p.Arg403Gln), c.1358G>A (p.Arg453His), and c.1498G>A (p.Glu500Lys). Based on the guidelines from the ACMG, the first 3 variants were classified as pathogenic, while c.1498G>A (p.Glu500Lys) was classified as likely pathogenic (PM1+PM2_Supporting+PM6+PP3), which was also unreported previously. The remaining four children had all harbored maternal variants, including MYL2: c.173G>A (p.Arg58Gln; classified as pathogenic), TPM1: c.574G>A (p.Glu192Lys) and ACTC1: c.301G>A (p.Glu101Lys)(both were classified as likely pathogenic), and MYBPC3: c.146T>G (p.Ile49Ser; classified as variant of uncertain significance). Seven children were treated with 0.5 ~ 3 mg/(kg·d) propranolol, and their symptoms had improved significantly. They were followed up until September 30, 2022 without further cardiac event., Conclusion: Genetic testing can clarify the molecular basis for unexplained cardiomyopathy and provide a basis for clinical diagnosis and genetic counseling. Discovery of the c.1498G>A (p.Glu500Lys) variant has also expanded the spectrum of MYH7 gene mutations underlying HCM.

Objective: To observe the association between clinical phenotypes of hypertrophic cardiomyopathy (HCM) patients and a rare calcium channel and regulatory gene variation (Ca 2+ gene variation) and to compare clinical phenotypes of HCM patients with Ca 2+ gene variation, a single sarcomere gene variation and without gene variation and to explore the influence of rare Ca 2+ gene variation on the clinical phenotypes of HCM. Methods: Eight hundred forty-two non-related adult HCM patients diagnosed for the first time in Xijing Hospital from 2013 to 2019 were enrolled in this study. All patients underwent exon analyses of 96 hereditary cardiac disease-related genes. Patients with diabetes mellitus, coronary artery disease, post alcohol septal ablation or septal myectomy, and patients who carried sarcomere gene variation of uncertain significance or carried>1 sarcomere gene variation or carried>1 Ca 2+ gene variation, with HCM pseudophenotype or carrier of ion channel gene variations other than Ca 2+ based on the genetic test results were excluded. Patients were divided into gene negative group (no sarcomere or Ca 2+ gene variants), sarcomere gene variation group (only 1 sarcomere gene variant) and Ca 2+ gene variant group (only 1 Ca 2+ gene variant). Baseline data, echocardiography and electrocardiogram data were collected for analysis. Results: A total of 346 patients were enrolled, including 170 patients without gene variation (gene negative group), 154 patients with a single sarcomere gene variation (sarcomere gene variation group) and 22 patients with a single rare Ca 2+ gene variation (Ca 2+ gene variation group). Compared with gene negative group, patients in Ca 2+ gene variation group had higher blood pressure and higher percentage of family history of HCM and sudden cardiac death ( P <0.05); echocardiographic results showed that patients in Ca 2+ gene variation group had thicker ventricular septum ((23.5±5.8) mm vs. (22.3±5.7) mm, P <0.05); electrocardiographic results showed that patients in Ca 2+ gene variation group had prolonged QT interval ((416.6±23.1) ms vs. (400.6±47.2) ms, P <0.05) and higher RV5+SV1 ((4.51±2.26) mv vs. (3.50±1.65) mv, P <0.05). Compared with sarcomere gene variation group, patients in Ca 2+ gene variation group had later onset age and higher blood pressure ( P <0.05); echocardiographic results showed that there was no significant difference in ventricular septal thickness between two groups; patients in Ca 2+ gene variation group had lower percentage of left ventricular outflow tract pressure gradient>30 mmHg (1 mmHg=0.133 kPa, 22.8% vs. 48.1%, P <0.05) and the lower early diastolic peak velocity of the mitral valve inflow/early diastolic peak velocity of the mitral valve annulus (E/e') ratio ((13.0±2.5) vs. (15.9±4.2), P <0.05); patients in Ca 2+ gene variation group had prolonged QT interval ((416.6±23.1) ms vs. (399.0±43.0) ms, P <0.05) and lower percentage of ST segment depression (9.1% vs. 40.3%, P <0.05). Conclusion: Compared with gene negative group, the clinical phenotype of HCM is more severe in patients with rare Ca 2+ gene variation; compared with patients with sarcomere gene variation, the clinical phenotype of HCM is milder in patients with rare Ca 2+ gene variation.

Hypertrophic cardiomyopathy (HCM) is the most common monogenic inherited myocardial disease in children, and mutations in sarcomere genes (such as MYH7 and MYBPC3 ) are the most common genetic etiology of HCM, among which mutations in the MYH7 gene are the most common and account for 30%-50%. MYH7 gene mutations have the characteristics of being affected by environmental factors, coexisting with multiple genetic variations, and age-dependent penetrance, which leads to different or overlapping clinical phenotypes in children, including various cardiomyopathies and skeletal myopathies. At present, the pathogenesis, course, and prognosis of HCM caused by MYH7 gene mutations in children remain unclear. This article summarizes the possible pathogenesis, clinical phenotype, and treatment of HCM caused by MYH7 gene mutations, in order to facilitate the accurate prognostic evaluation and individualized management and treatment of the children with this disorder.

Objective: To analyze the clinical phenotype and MYH7 gene variant in a Chinese pedigree affected with hypertrophic cardiomyopathy (HCM)., Methods: The proband was screened for variant of 96 cardiomyopathy-associated genes by exonic amplification and high-throughput sequencing. Candidate variant was verified by Sanger sequencing among 300 healthy controls as well as family members of the proband. Co-segregation analysis of genotypes and clinical phenotypes was carried out for the pedigree. Clustal X software was used to analyze the sequence conservation of the variant among various species, and its pathogenicity was predicted by using bioinformatics software., Results: 6 out of 12 members from this pedigree were found to harbor heterozygous c.4124A>G (p.Tyr1375Cys) variant of the MYH7 gene, among whom five were diagnosed with HCM. The remaining one had failed to meet the diagnostic criteria for HCM, but had abnormal ECG. The same variant was not found in the 300 healthy controls. Amino acid sequence analysis showed that the variant is located in a highly conserved region, and bioinformatics analysis predicted that this variant may affect protein function and has a deleterious effect. Based on the American College of Medical Genetics and Genomics (ACMG) guidelines, the variant was predicted to be likely pathogenic (PM2+ PP1&#95;Moderate+PP3+PP5)., Conclusion: The c.4124A>G (p.Tyr1375Cys) variant of the MYH7 gene probably underlay the pathogenesis in this pedigree. Above finding has important value for the early diagnosis of patients with HCM.

Objective: To explore the clinical characteristics and mutation spectrum of ALPK3-related pediatric cardiomyopathy and craniofacial-skeletal abnormalities in children. Methods: The clinical data during a follow-up of 11 years including clinical features, echocardiogram, electrocardiogram, cardiac magnetic resonance, genetic testing, and other data of a child firstly diagnosed with ALPK3 gene-related cardiomyopathy and craniofacial-skeletal abnormalities in China were collected retrospectively. The literatures containing the keyword of "ALPK3 gene" published in the China National Knowledge Infrastructure, Wanfang database and PubMed were collected up to November 2020. Then, the clinical features and gene mutations of ALPK3 gene-related pediatric cardiomyopathy with craniofacial-skeletal features were summarized. Results: A female patient aged 10 months who presented with an enlarged heart for 2 months, was admitted to the hospital and initially diagnosed with endocardial elastic fibrosis. The echocardiography showed features of dilated left ventricle (LV) and LV systolic dysfunction. Low-set ears, webbed neck, a grade 2/6 systolic murmur at lower left sternal area and bilateral absent flexion creases of dig were observed. After treatment, the size and function of the heart recovered to normal at age 13 months. However, the ventricular septum and LV wall were thicker than normal values. Then, the diagnosis was revised to hypertrophic cardiomyopathy(HCM) and suspected congenital malformation syndrome. LV hypertrophy (LVH) progressed slowly before the age of 8 years and then progressed rapidly. At age 9 years, compound heterozygous ALPK3 mutations (c.721dup, p.Y241Lfs*42(exon 1) and c.4840C>T, p.R1614*(exon 10)) were detected in the proband and the mutations had not been reported previously. Then, the final diagnosis of ALPK3 gene-related pediatric cardiomyopathy with craniofacial-skeletal features was made. During the follow up of 11 years, regular follow-up echocardiographic images showed progressive LVH. At age 11 years, electrocardiogram showed LVH, ST-T changes in multiple-lead, T wave inversion, and prolonged QT intervals. Cardiac magnetic resonance showed biventricular hypertrophy and late gadolinium enhancement showed non-uniform enhancement of left and right ventricular myocardium. A total of 7 articles published in English were retrieved, and no Chinese literature was found. Twenty-eight cases were reported in the articles plus the patient in this study. Twenty-four mutations were reported worldwide, 18 patients carried homozygous mutations and 10 patients compound heterozygous mutations. Eleven patients showed dilated cardiomyopathy (DCM) at early stage of disease, and 10 of them transitioned to HCM at the disease progression stage. Eight patients presented with HCM at early stage of disease. Nine patients initially exhibited a mixed phenotype of DCM and HCM, and 6 of them eventually progressed to HCM. Electrocardiogram showed prolonged QT interval. Extracardiac features included short stature, special face, cleft palate, webbed neck, joint contracture, and scoliosis, etc. Conclusions: Progressive myocardial hypertrophy is a major feature of ALPK3 gene-related cardiomyopathy with craniofacial-skeletal malformations. Precise diagnosis depends on molecular genetic techniques. More cases should be accumulated for further analysis on the genotype-phenotype correlation and prognosis assessment.

Objective: To analyze the clinical and genetic characteristics of clinical subtypes of non-obstructive hypertrophic cardiomyopathy (HCM). Methods: It was a cohort study. Patients with non-obstructive HCM admitted to Fuwai Hospital, Chinese Academy of Medical Sciences, from January 1999 to April 2019 were enrolled. According to the characteristics of cardiac morphology and function shown by echocardiography, the patients were divided into common type, dilated type, restricted type and reduced ejection fraction type. The clinical data of the patients were recorded, and 8 sarcomere pathogenic genes were screened by full exon sequencing or panel sequencing. Patienst were followed up and cardiovascular endpoint events were recorded. Results: A total of 815 patients with non-obstructive HCM were enrolled, including 27 (3.3%) restricted type, 51 (6.3%) dilated type, 30 (3.7%) reduced ejection fraction type and 707 (86.7%) common type. A total of 704 out of 815 patients underwent genetic testing. Among them, 299 (42.5%) patients carried at least 1 sarcomere gene mutation. MYBPC3 and MYH7 mutation accounted for 42.1% (126/299) and 35.8% (107/299) respectively. 66.7% (16/24) of the patients with restricted type carried sarcomere gene mutation, which was higher than that in patients with dilated type (36.4% (16/44)) and in common type (41.5% (250/602), P =0.015). Among the patients with reduced ejection fraction, 56.7% (17/30) patients carried sarcomere gene mutations, 23.3% (7/30) carried multiple sarcomere mutations, which was higher than that in restricted type (8.3% (2/24)), in dilated type (9.1% (4/44)) and in common type 4.2% ((24/577), P <0.001). MYH7 and MYBPC3 were the main mutation gene types of all clinical subtypes, and the genotypes were similar among groups (all P >0.05). Seven hundred and three out 815 patients were followed up for 2.9 (1.4, 4.0) years. There were 53(7.5%) cardiovascular death. Cardiovascular death occurred in 5.0% (29/578) patients with common type, 13.0% (3/23) patients with restricted type, 16.3% (7/43) patients with dilated type and 46.7% (14/30) patients with decreased ejection fraction. Univariate Cox proportional hazards model analysis showed that the risk of cardiovascular death in patients with restricted, dilated and reduced ejection fraction type was higher than that in patients with common type ( P <0.001). After adjusting for gender, age of onset, body mass index, history of hypertension, coronary heart disease and diabetes, multivariate Cox proportional hazards model analysis showed that the HR of cardiovascular death in patients with restricted, dilated and reduced ejection fraction type were 5.454 (95% CI 1.137-26.157, P =0.034) and 6.597 (95% CI 1.632-26.667, P =0.008) and 9.028 (95% CI 2.201-37.039, P =0.002) respectively, as compared to patients with common type. Conclusions: Most of the patients with non-obstructive HCM are common type, featured by mild clinical manifestations and good prognosis. Although the proportion of restricted type and dilated type is relatively low, and cardiac systolic function is mostly preserved, the clinical phenotype and prognosis of these patients are similarly severe and poor as patients with reduced ejection fraction. The genotypes are similar in different clinical subtypes, but the proportion of patients with sarcomere gene mutation is higher in restricted type, and the proportion of patients with multiple sarcomere gene mutation is higher in decreased ejection fraction type.

Objective: To explore the predictive value of overall longitudinal strain for the development of cardiomyopathy without hypertrophic changes., Methods: Sixty five patients with suspected hypertrophic cardiomyopathy (HCM) but without hypertrophic changes were selected. Genetic variant, overall longitudinal strain, left ventricular ejection fraction, end diastolic volume, end systolic volume, interventricular septal thickness, left ventricular diameter and end diastolic diameter were detected. The risk factors of HCM were analyzed., Results: Forty four variants of 16 genes were identified, among which MYBPC3 13659G>A was the commonest (73.20%) and MYH7 13252C>T was the second (31.25%). MYBPC3 GG genotype, overall longitudinal strain and apical longitudinal strain were correlated with HCM (P<0.05)., Conclusion: The increase of longitudinal strain is of great value in predicting the occurrence of HCM.

Objective: To evaluate the cardiac functional changes in hypertrophic cardiomyopathy(HCM) patients with β-myosin heavy chain gene (MYH7) mutations by three-dimensional (3D) speckle tracking imaging(3D-STI) and conventional echocardiography modalities, and then to explore the potential predictors of adverse cardiovascular events in these patients. Methods: A consecutive series of 192 HCM patients admitted in our center from October 2014 to October 2016 were genetically screened to identify MYH7 mutations in this retrospective study. A total of 43 HCM patients with MYH7 mutations were enrolled. The patients were divided into events group( n= 13) and no event group( n= 30) according to the presence or absence of adverse cardiovascular events(primary and secondary endpoints). All patients were followed up to January 2019 after comprehensive evaluation of 3D-STI, two-dimensional and Doppler echocardiography. The adverse cardiovascular events were recorded. Results: The median follow up time was 1 012 (812, 1 330) days. During follow-up, 13 patients (30.2%) reached endpoints: 6 cases of the primary endpoints(2 cases of sudden cardiac death(SCD), 3 cases of survival after defibrillation, and 1 case of appropriate implantable cardioverter-defibrillator(ICD) discharge); 7 cases of the second endpoints(5 cases of heart failure hospitalization, 1 case of syncope and cardioversion due to supraventricular tachycardia, and 1 case of end-stage HCM). Patients with adverse cardiovascular events had higher prevalence of syncope and risk of SCD, enlarged left atrial volume index(LAVI) and reduced 3D left ventricular global longitudinal train (3D-GLS), as compared to those without adverse events(all P< 0.05). The multivariate Cox regression analysis showed that reduced 3D-GLS( HR =0.814, 95 %CI 0.663-0.999, P= 0.049) was an independent predictor for adverse cardiovascular events. The cutoff value of 3D-GLS≤13.67% was linked with significantly increased risk of adverse cardiovascular events in this patient cohort( AUC =0.753, 95 %CI 0.558-0.948, sensitivity 86%, specificity 69%, P< 0.05). The Kaplan-Meier analysis indicated that the patients with the 3D-GLS≤ 13.67% faced higher risk of death than those with 3D-GLS>13.67%. Conclusion: 3D-GLS is useful on predicting adverse cardiovascular events in HCM patients with MYH7 mutations.

Objective: To analyze and summarize the diagnosis and treatment experience of common inherited cardiac arrhythmia syndrome in pediatric patients, and explore the most appropriate therapy. Methods: A retrospective review identified 30 pediatric cases (19 males, 11 females) diagnosed with long QT syndrome (LQTS), Brugada syndrome (BrS), catecholaminergic polymorphic ventricular tachycardia (CPVT), hypertrophic cardiomyopathy (HCM), arrhythmogenc right ventricular cardiomyopathy (ARVC) from January 2008 to December 2018 in the Pediatric Cardiology Department, Guangdong Provincial People's Hospital. Data obtained included the diagnosis, treatment and follow-up outcome. Results: The most common inherited cardiac arrhythmia syndromes were LQTS ( n= 14) including 1 case with epilepsy, CPVT ( n= 5), HCM ( n= 7), ARVC ( n= 1), and BrS ( n= 3). Twenty-seven cases were admitted to hospital due to syncope, whereas the remaining 3 cases of BrS had not presented with syncope before admission. The average onset age of inherited arrhythmia was (10.0±3.3) years. Genetic testing was performed on 20 patients. The median follow-up time was 40 months. Among 15 patients who underwent implantable cardioverter defibrillator (ICD) and survived, 2 patients had frequent ICD discharge. One patient underwent radiofrequency ablation, and the other one received left cardiac sympathetic denervation and an increased ICD defibrillation threshold, and the number of ICD discharge was significantly reduced. Among 10 patients who received drug therapy, 4 patients including two patients who discontinued treatment without advices died. Two patients whose parents refused treatment died, 1 case diagnosed with unexplained sudden cerebral death, and the remaining 2 cases without indication for drug therapy survived without any treatment. Conclusions: Mortality rate is high in pediatric patients with inherited cardiac arrhythmia and syncope. The therapeutic effect of drugs are not satisfactory, ICD implantation is the most effective treatment to prevent sudden cardiac death currently, but the postoperative frequent discharge should be brought to the forefront and handled in time.

Objective: To explore the genotype-phenotype correlation of a MYH7-D554Y mutation identified in an ethnic Han Chinese pedigree affected with hypertrophic cardiomyopathy., Methods: Ninety six cardiovascular disease-related genes were detected in the proband by exonic amplification and high-throughput sequencing. Suspected mutations were verified by Sanger sequencing among 300 healthy controls as well as family members of the proband. The pathogenicity and conservation of the detected mutations were analyzed with ClustalX, MutationTaster, PolyPhen-2, Provean and SIFT software., Results: Four of the 5 first-degree relatives of the proband were diagnosed with hypertrophic cardiomyopathy. The proband has featured extremely hypertrophic left ventricular wall with a maximal thickness of 35 mm. Genetic testing showed that four of them have carried a heterozygous c.1660G>T (p.Asp554Tyr) mutation of the MYH7 gene, who the remaining one was phenotypically normal and did not carry the mutation. The mutation has not been recorded by the Human Gene Mutation Database (HGMD) and other databases. Bioinformatics analysis suggested that the mutation site is highly conserved and that the mutation is pathogenic., Conclusion: The p.Asp554Tyr mutation of the MYH7 gene probably underlies the hypertrophic cardiomyopathy in this pedigree.

Objective: To analyze the gene mutations and clinical features of patients with Noonan syndrome and hypertrophic cardiomyopathy. Method: Determined the mutation domain in five cases diagnosed with Noonan syndrome and hypertrophic cardiomyopathy and identified the relationship between the mutant domain and hypertrophic cardiomyopathy by searching relevant articles in pubmed database. Result: Three mutant genes (PTPN11 gene in chromosome 12, RIT1 gene in chromosome 1 and RAF1 gene in chromosome 3) in five cases all had been reported to be related to hypertrophic cardiomyopathy. The reported hypertrophic cardiomyopathy relevant genes MYPN, MYH6 and MYBP3 had also been found in case 1 and 2. Patients with same gene mutation had different clinical manifestations. Both case 4 and 5 had RAF1 mutation (c.770C>T). However, case 4 had special face, low IQ, mild pulmonary artery stenosis, and only mild ventricular hypertrophy. Conclusion: Noonan syndrome is a genetic heterogeneity disease. Our study identified specific gene mutations that could result in Noonan syndrome with hypertrophic cardiomyopathy through molecular biology methods. The results emphasize the importance of gene detection in the management of Noonan syndrome.

Objective: To analyze the phenotype-genotype correlation of MYH7-V878A mutation., Methods: Exonic amplification and high-throughput sequencing of 96-cardiovascular disease-related genes were carried out on probands from 210 pedigrees affected with hypertrophic cardiomyopathy (HCM). For the probands, their family members, and 300 healthy volunteers, the identified MYH7-V878A mutation was verified by Sanger sequencing. Information of the HCM patients and their family members, including clinical data, physical examination, echocardiography (UCG), electrocardiography (ECG), and conserved sequence of the mutation among various species were analyzed., Results: A MYH7-V878A mutation was detected in five HCM pedigrees containing 31 family members. Fourteen members have carried the mutation, among whom 11 were diagnosed with HCM, while 3 did not meet the diagnostic criteria. Some of the fourteen members also carried other mutations. Family members not carrying the mutation had normal UCG and ECG. No MYH7-V878A mutation was found among the 300 healthy volunteers. Analysis of sequence conservation showed that the amino acid is located in highly conserved regions among various species., Conclusion: MYH7-V878A is a hot spot among ethnic Han Chinese with a high penetrance. Functional analysis of the conserved sequences suggested that the mutation may cause significant alteration of the function. MYH7-V878A has a significant value for the early diagnosis of HCM.

Objectives: To analyze the related pathogenicity gene mutations in a sudden death of hypertrophic cardiomyopathy （HCM） on whole exome level., Methods: Whole exome sequencing （WES） was been performed on a sudden death case sample with pathological features of HCM by Illumina® Hiseq 2500 platform. Using hg19 as the reference sequences, the sequencing data were analyzed. Suspicious single nucleotide variants （SNV） were screened, and the conservatism and function were analyzed by the software such as PhyloP, PolyPhen-2, SIFT, etc., Results: After screening, a heterozygous mutation C719R was finally identified in the gene MYBPC3 of this case., Conclusions: The molecular anatomy on whole exome level by second generation sequencing technology can help to define the molecular mechanism of HCM and provide a new mothed and thought for analysis of death cause., Competing Interests: The authors of this article and the planning committee members and staff have no relevant financial relationships with commercial interests to disclose., (Copyright© by the Editorial Department of Journal of Forensic Medicine)

Objective: In this study, the sreening of candidate pathogenic gene is done among family members of an dilated cardiomyopathy(DCM)and hypertrophic cardiomyopathy (HCM) coexistence, and find the relationship between the genotype and the phenotype., Methods: The inheritance atlas was drawn, analysis of genetic characteristics and clinical phenotype.Peripheral venous blood samples of proband and family members were candidated gene exon high-throughput sequencing sub target capture, make the result compares with related database, ultimately screening the target area of the exon and mutations of candidate genes and then using bidirectional sequencing of Sanger to sequence other family members and the health group which were matching with gender and age to testify whether there is the above mutations., Results: In this family, the proband and his father carry three missense mutations, about TTNc.604 A>G(p.Lys202Glu)、TAZ c. 580A>G(p.Ile194Val)and MYH7c.730 T>C(p.Phe244Leu). The heart function of proband was failure, and accompanied malignant arrhythmia.But his father has no obvious clinical symptoms.In this family, the same genetic mutation of disease causing gene lead to different clinical phenotype, but different genetic mutation of disease causing gene lead to the same clinical phenotype.None of the mutations found in this family was found in the health group., Conclusion: The patient of this family carries the genetic mutation of MYH7, TTN and TAZ.The patient of this family carries the composite mutation of MYH7(+) /TTN(+) heterozygous missense mutation and TAZ(+) /TTN(+) heterozygous missense mutation may be show the performance of the genetic characteristics of early onset, severe phenotype.

Objective: To identify the potential mutations in a Chinese pedigree with hypertrophic cardiomyopathy (HCM), and to analyze the genotype-phenotype relationship in this pedigree., Methods: Clinical history and physical examinations, electrocardiography (ECG), echocardiography (UCG), cardiac magnetic resonance (CMR) data were obtained from 10 members of a three-generation Chinese family with HCM. A total of 96 genes related to hereditary cardiomyopathy were detected by exon and boarding intron analyses in the proband using second-generation sequencing. Mutations identified in the proband were confirmed by bi-directional Sanger sequencing in the rest 9 family members and 300 healthy controls., Results: Three mutations, including MYBPC3-P1208fs, ANK2-H556R and ANK2-P1974H, were identified in this pedigree. MYBPC3-P1208fs gene mutation was detected in 3 family members (proband, his mother and son), while this mutation was not detected in the rest family members. HCM was diagnosed in the proband and his mother by ECG, UCG and CMR. Son of the proband demonstrated early phenotype of HCM: although UCG and CMR were normal, ECG showed sinus bradycardia and paroxysmal supraventricular arrhythmias as well as ST segment changes. The onset age of HCM diagnosis of the proband and his mother was 42 and 50 years old, presented with palpitation and chest pain, and myocardial fibrosis sign in CMR. Furthermore, we found that left ventricular myocardial fibrosis is related to ECG changes (increasing r wave, ST segment change) in the proband and his mother. No HCM phenotype was evidenced in the 7 family members carrying ANK2-H556R and ANK2-P1974H mutations., Conclusions: Our results show that MYBPC3-P1208fs gene mutation is associated HCM phenotype in this Chinses pedigree. This mutation is associated with myocardial fibrosis and ST changes in HCM phenotype in this pedigree while ANK2-H556R and ANK2-P1974H mutations are not related to HCM phenotype in this family.

Objective: To identify the casual mutation of a Chinese pedigree with hypertrophic cardiomyopathy (HCM), and to analyze the genotype-phenotype relationship., Methods: The coding exons of 26 reported disease genes were sequenced by targeted resequencing in the proband and the identified mutation were detected with bi-directional Sanger sequencing in all family members and 307 healthy controls. The genotype-phenotype correlation was analyzed in the family., Results: A missense mutation (c.2191C > T, p. Pro731Ser) in the 20th exon of MYH7 gene was identified. This mutation was absent in 307 healthy controls and predicted to be pathogenic by PolyPhen-HCM. Totally 13 family members carried this mutation, including 10 patients with HCM and 3 asymptomatic mutation carriers. The proband manifested severe congestive heart failure and 8 patients expressed various clinical manifestations of heart failure, including dyspnea, palpitations, chest pain, amaurosis or syncope. Five patients were diagnosed as HCM at the age of 16 or younger. One family member suffered sudden cardiac death., Conclusions: The Pro731Ser of MYH7 gene mutation is a causal and malignant mutation linked with familiar HCM.

Objective: Mitochondrial disease is a group of energy metabolic disorders, characterized by involvement of multisystem with high energy requirements. Encephalomyopathies are common clinical findings of the mitochondrial diseases. However, mitochondrial cardiac damage is not rare. In this study, the clinical, biological, and genetic analyses were performed in three patients with mitochondrial cardiac damage, in order to understand the characteristics of mitochondrial diseases., Method: Three girls presented with arrhythmia and cardiac enlargement from the age of 3, 4 and 8 years respectively. They were admitted into the Peking University First Hospital. Infection, autoimmune diseases, aminoacidopathies, organic acidurias, mitochondrial-fatty acid oxidation defects, and lysosomal storage disease were excluded by routine laboratory examinations and metabolic analysis for blood amino acids, acylcarnitines, urinary organic acids, and lysosome activity assay. Peripheral leukocytes mitochondrial respiratory chain enzyme I to V activities were measured by spectrophotometry. The entire sequence of the mitochondrial DNA was analyzed., Result: In two patients (case 1 and case 3), hypertrophic cardiomyopathy and grade I to grade II of cardiac function were found. One patient (case 2) was diagnosed with arrhythmia and grade I of cardiac function. Increased creatine phosphokinase and creatine kinase isoenzyme MB were observed. Mitochondrial respiratory chain complex deficiencies were indentified in the three patients. Patient 1 had combined deficiencies of complex III and V. The activity of complex I+III was 18.7 nmol/(min·mg mitochondrial protein) (control 84.4 ± 28.5). The activity of complex V was 20.4 nmol/(min·mg mitochondrial protein) (control 103.7 ± 29.2). In her mitochondrial gene, A14693G on tRNA(Glu) and T16519C on D-loop were found. Patient 2 had an isolated complex I deficiency. The activity was 22.0 nmol/(min·mg mitochondrial protein) (control 44.0 ± 5.4). A16183C, T16189C and G15043A mutations on D-loop were found. Patient 3 had a combined deficiency of complex IV and V. The activity of complex IV was 21.0 nmol/(min·mg mitochondrial protein) (control 54.1 ± 12.3). The activity of complex V was 23.2 nmol/(min·mg mitochondrial protein) (control 103.7 ± 29.2). C253T and C16187T mutations on D-loop were detected. Haplotype analysis showed that three patients belong to H2a2a. Improvement was observed after the treatment with L-carnitine, coenzyme Q10, vitamin C and E. At present, the patients are 7, 5 and 8 years old. Although excise intolerance still persists, they had a good general condition with normal school life., Conclusion: The mitochondrial diseases with cardiac damage show cardiomyopathy, arrhythmia and exercise intolerance. Many kinds of mitochondrial respiratory chain deficiency were observed. A14693G in mitochondrial tRNA(Glu) gene is probably one of the causes in China.

Objective: To screen the cardiac troponin T (TNNT2) mutations in Chinese patients with hypertrophic cardiomyopathy (HCM) and to analyze the potential link between the genotype and the phenotype., Methods: Clinical features of 100 probands with HCM and some family members were evaluated, 200 unrelated normal subjects served as control. The exons and flanking introns of TNNT2 were amplified with PCR and direct sequencing was used to screen TNNT2 mutations/polymorphisms., Results: Two novel missense mutations were detected in 2 HCM patients: R92W and R286H. These 2 mutations were not found in 200 non-HCM controls. A five-basepair insertion/deletion polymorphism in intron 3 of TNNT2 was identified in this HCM cohort but was not related to the phenotype., Conclusions: Two missense mutations, R92W and R286H, were found in 2/100 patients with HCM, TNNT 2 mutation is relatively low in Chinese patients with HCM.

Objective: To study cardiac troponin T (TNNT2) gene mutations in Chinese patients with hypertrophic cardiomyopathy (HCM) and analyze the correlation between the genotype and phenotype., Methods: Ninety-five unrelated Chinese patients with HCM and 120 control individuals were screened for TNNT2 gene mutations. Seven exons (8, 9, 10, 11, 14, 15, and 16) in the functional regions of TNNT2 gene were amplified using PCR and the products were sequenced. The patients with positive results underwent further family screening., Results and Conclusion: This study did not find any HCM-caused mutations in TNNT2 gene, a result different from the reported rates of TNNT2 gene mutation ranging from 10% to 20% in other nations, suggesting that TNNT2 gene is not a susceptible gene for HCM in Chinese population.

Objective: To detect the gene mutations of beta-myosin heavy chain gene (MYH7) in Chinese pedigrees with hypertrophic cardiomyopathy (HCM), and to analyze the correlation between the genotype and phenotype., Methods: Exons 3, 5, 7-9, 11-16 and 18-23 of the MYH7 gene were amplified with PCR in three Chinese pedigrees with HCM. The products were sequenced. Sequence alignment between the detected and the standard sequences was performed., Results: A missense mutation of Thr441Met in exon 14 was identified in a pedigree, which was not detected in the controls. Several synonymous mutations of MYH7 gene were detected in the three pedigrees., Conclusion: The mutation of Thr441Met, located in the actin binding domain of the globular head, was first identified in Chinese. It probably caused HCM. HCM is a heterogeneous disease. Many factors are involved in the process of its occurrence and development.

Hypertrophic Cardiomyopathy (HCM) is a primary cardiac disorder characterized by asymmetric thickening of the septum and left ventricular wall. HCM affects 1 in 500 individuals in the general population, and it is the most common cause of sudden death in the young and athletes. The clinic phenotype of HCM is highly variable with respect to age at onset, degree of symptoms, and risk of sudden death. HCM is usually inherited as a Mendelian autosomal dominant trait. To date, over 900 mutations have been reported in HCM, which were mainly located in 13 genes encoding cardiac sarcomere protein, e.g., MYH7, MYBPC3, and TnT. In addition, more and more mitochondrial DNA mutations were reported to be associated with the pathogenesis of HCM. Based on the description of the clinical phenotype and morphological characteristics, this review focuses on the research in the molecular pathogenic mechanism of HCM and its recent advances.

Hypertrophy cardiomyopathy (HCM) is an autosomal dominant disorder characterized by increased heart mass that occurs without a defined stimulus (such as hypertension or valvular disease). It is commonly recognized through the widespread use of non-invasive imaging. Epidemiological studies indicate that 1 of 500 individuals has unexplained cardiac hypertrophy, an observation that predicts a considerable role for genetics in this enigmatic disorder. Indeed, to date, more than 500 mutations had been identified in more than 12 genes encoding components of the thick and thin filament of the sarcomere and other myofilament-related proteins. Intensive studies of HCM continue to take our understandings about this fascinating disease in new directions. Mechanistic analyses have provided insights into how mutational alterations in these structural proteins may trigger the hypertrophic remodeling processes and other associated clinical features of HCM. Based on these studies, investigations have been initiated to assess whether early pharmacological interventions could prevent or attenuate the development of the disease and its clinical sequelae. By combining pathophysiology with knowledge of genetic cause and molecular responses, HCM has begun to exemplify opportunities for predictive and personalized medicine. With the emergence of newer technologies that enable high-throughput sequencing of DNA, it is timely to review clinical manifestations and genetic causes of this unique disease, and how intertwining these insights can improve contemporary diagnosis and management of HCM and other genetic forms of cardiac hypertrophy.

Objective: To identify the disease-causing gene mutations and to reveal the relationship between the genotype and the phenotype in Chinese patients with hypertrophic cardiomyopathy (HCM)., Methods: One hundred unrelated patients with HCM and 120 controls were enrolled in this study. The full encoding exons and flanking sequences of the cardiac myosin binding protein C gene (MYBPC3) were amplified with PCR and the products were sequenced., Results: A novel missense mutation c.706T > C was identified in exon 6 of MYBPC3 gene in three HCM patients, which resulted a Serine (S) to Glycine (G) exchange at amino acid residue 236 (S236G). The clinical phenotypes of the three patients were different (2 obstructive HCM, 1 non-obstructive HCM). The 120 controls were normal in the genetic test., Conclusions: The novel S236G mutation in MYBPC3 gene was a hot-spot mutation in Chinese patients with HCM.

Objective: To detect gene mutations associated with hypertrophic cardiomyopathy (HCM) in Chinese patients and possible correlations between genotype and phenotype., Methods: Twenty-one unrelated patients with hypertrophic cardiomyopathy were studied. The clinical data including symptoms, physical examination, echocardiography and electrocardiography were collected. The full ecoding exons of cardiac myosin-binding protein C gene (cMYBPC3) were amplified with PCR and the products were sequenced., Results: Two mutations were identified in probands from two families. One mutation was frame shift mutation Pro1208fs in the exon 32 of the cMYBPC3 gene. Pro1208fs mutation was identified in a 59 years old female patient with familial hypertrophic cardiomyopathy. Symptom onset was late and a favorable clinical course was evidenced in this patient. Another mutation was missence mutation Gly507Arg in the exon 17 of the MYBPC3 gene identified in a 24 years old male patient. Diffuse thickness of left ventricular wall, impaired diastolic function and enlarged left atria were evidenced in echocardiography. No mutation was identified in the 80 control healthy individuals., Conclusion: cMYBPC3 might be the disease-causing genes in Chinese patients with hypertrophic cardiomyopathy.

Objective: To screen the MYBPC3 gene mutations in Han Chinese patients with hypertrophic cardiomyopathy (HCM)., Methods: Sixty-six patients with HCM were enrolled for the study. The exons in the functional regions of MYBPC3 were amplified with PCR and the products were sequenced., Results: Four novel mutations and four common polymorphisms were identified in this patient cohort. A Lys301fs mutation in exon10 was evidenced in a H30, and when he was 47 years old, he had the chest tightness, shortness of breath with septal hypertrophy of 18.7mm; a Asp463stop mutation in exon17 was detected in a H48, he was 24 years old 24-year-old when a medical examination showed ventricular septal hypertrophy of 15.4 mm; both Gly523Arg mutation in exon18 and Tyr847His mutation in exon26 were found in a H53 with onset age 36 years old, feeling chest tightness after excise and his ventricular septal hypertrophy was 27 mm that time. MYBPC3 mutations occurred in 4.5% patients in this cohort. These mutations were not found in 100 non-HCM control patients., Conclusion: MYBPC3 mutation is presented in a small portion of Han Chinese patients with HCM.

Hypertrophic cardiomyopathy (HCM) is caused by dominant mutations in sarcomere genes. The diagnosis of HCM is usually established by identifying unexplained left ventricular hypertrophy (LVH) on cardiac imaging studies; however, LVH is not an invariable feature of disease. The expression of LVH is highly age-dependent, and LV wall thickness is frequently normal during childhood. Overt development of hypertrophy, and the ability to make a clinical diagnosis, does not typically occur until adolescence or later. Genetic testing allows identification of family members who have inherited the pathogenic sarcomere mutation (G +) before the emergence of clinical manifestations (LVH -). As such, a new and important subset of individuals with preclinical HCM (G+ / LVH-) can be identified early in life, before a clinical diagnosis can be made. Our evaluation of preclinical HCM has indicated that although there are no distinguishing morphologic features of early disease, there is evidence of myocardial dysfunction prior to the development of LVH. Subtle impairment of diastolic function is detectable in otherwise healthy sarcomere mutation carriers and can differentiate these family members from those who did not inherit the mutation. In contrast, systolic function appears relatively preserved in preclinical HCM, but impaired in overt disease. This preliminary finding suggests that both the sarcomere mutation and the characteristic changes in myocardial architecture (LVH, fibrosis and disarray) are required to perturb force generation. By studying this intriguing preclinical cohort, we can better understand the early stages of disease pathogenesis and potentially develop therapy to alter the clinical expression of sarcomere mutations.

Objective: To observe the disease-causing gene mutation in Chinese patients with hypertrophic cardiomyopathy and to analyze the correlation between the genotype and the phenotype., Methods: Specimens of peripheral blood were collected and the genome DNA was extracted in 65 unrelated patients with hypertrophic cardiomyopathy and 60 normal controls. The exon 7 and 8 of cardiac troponin I gene were screened with PCR and direct sequencing technique., Results: A missense mutation in the exon 7 of the cardiac troponin I gene was identified in a 40-year-old male patient with hypertrophic cardiomyopathy (Asp127Tyr) which was absent in the controls., Conclusion: A novel missense mutation of cardiac troponin I was identified in a patient with hypertrophic cardiomyopathy, this mutation might be the disease-causing gene mutation in this Chinese patient.

Objective: To screen the disease-causing gene mutation in Chinese patients with familiar hypertrophic cardiomyopathy (HCM) and to analyse the correlation between the genotype and phenotype., Methods: Eight Chinese pedigrees with HCM and 80 age-matched normal control subjects were studied. The exons in the functional regions of the beta myosin heavy chain gene (beta-MHC) were amplified with PCR and the products were sequenced. The relation between the genotype and phenotype was analyzed., Result: Val606Met mutation was identified in exon 16 in one family and Val606Met mutation was identified in 4 out of 8 family members in this pedigree and 3 out of 4 Val606Met carriers suffered from HCM. No similar mutation was identified in controls., Conclusion: The Val606Met mutation located at the actin-binding region of the cardiac beta-MHC gene is involved in the pathogenesis of HCM in this Chinese pedigree.

Objective: To investigate the effects of cardiac troponin I R145W mutation, detected in Chinese patients with hypertrophic cardiomyopathy, on Ca(2+) current modulation., Methods: R146W mutation (resemble R145W in human) was introduced into rat cardiac troponin I cDNA by site-directed mutagenesis. With EGFP as a reporter gene, replication-defective adenovirus containing the wild or mutant cTnI gene was constructed. Adult rat cardiomyocytes, were isolated by Langendorff perfusion and cultured with serum-free medium and transduced with the recombinant adenoviruses. Western blot was used to determine the recombinant proteins. Whole cell patch clamp was employed to record L-type Ca(2+) currents on cultured myocytes. Intracellular free Ca(2+) and caffeine-induced sarcoplasmic reticulum (SR) Ca(2+) release were determined after the cells incubated with Fura-2/AM., Results: DNA sequencing confirmed that R146W mutation was generated in rat cTnI cDNA. Bright green fluorescence was observed in the cultured cardiomyocytes at 48 h after transduction. The recombinant proteins could be identified with cTnI or GFP monoclonal antibody. The peak current of L-type Ca(2+) channel in cells transduced with cTnI R146W was significantly decreased compared to control cells and cells transfected with wild cTnI. Intracellular free Ca(2+) concentrations and caffeine-induced SR Ca(2+) release determined by Fura-2/AM were similar among various cells., Conclusion: Reduced peak current of L-type Ca(2+) channel in cells transduced with cTnI R146W might contribute to the disease-causing mechanism of this mutation in patients with hypertrophic cardiomyopathy.

Objective: To study the disease-causing gene mutation in Chinese patients with familial hypertrophic cardiomyopathy (FHC) and to analyze the correlation between the genotype and the phenotype., Methods: Peripheral blood samples were collected from 40 members from a family affected with FHC, and 120 healthy volunteers. PCR was performed to analyze the exons and flanking introns of the cardiac troponin T gene (TNNT2), beta-myosin heavy chain gene (MYH7), and myosin-binding protein C gene (MYBPC3) and the products were sequenced. The clinical data including symptom, physical examination, echocardiography and electrocardiography were collected., Results: A 14035c > t mutation, which causes a missense mutation (R130C) in exon 10 of TNNT2 gene were identified in 4 family members, including the proband, female, aged 53, with the onset at the age of 30. The 4 persons with the 14035c > t mutation, all FHC patients, presented left ventricular dysfunction with a penetrance of 100%. Two of the patients died of sudden cardiac death during follow-up. No mutation was identified in the MYH7 and MYBPC3 genes., Conclusion: The 14035c > t mutation of TNNT2 gene is the causal mutation of FHC which is associated with malignant phenotype with a penetrance of 100%. It is a reasonable procedure in HCM patients with malignant phenotype to screen mutation in the TNNT2 gene.

Objective: To study the disease-causing gene mutation in Chinese patients with hypertrophic cardiomyopathy (HCM) and to analyze the genotype and phenotype correlation., Methods: One family (n = 27) affected with HCM were chosen for the study. The full encoding exons and flanking sequences of beta-myosin heavy chain gene (MYH7) and cardiac myosin-binding protein C gene (MYBPC3) were amplified with PCR and the products were sequenced. The clinical data including symptom, physical, echocardiography and electrocardiography examinations were collected., Results: We identified a 13261 G > A mutation, which causes a missense mutation (G758D) in exon 23 of MYBPC3 in 9 family members. One mutation carrier suffered from dilated cardiomyopathy (DCM) with asymmetric interventricular septal hypertrophy (14 mm). Another mutation carrier was diagnosed as HCM., Conclusions: The 13261 G > A mutation is associated with a DCM-like HCM and HCM phenotype in this Chinese family affected with HCM.

Objective: To compare the gene mutation between Chinese patients with familial and sporadic hypertrophic cardiomyopathy (HCM)., Methods: Peripheral blood samples were collected from 36 patients with familial HCM (FHCM) and 50 patients with sporadic HCM (SHCM), all un-related and from different provinces of China. PCR was used to amplify the 26 protein-coding axons of beta-myosin heavy chain (MYH7), 16 exons for cardiac troponin T (TNNT2), and 38 exons for cardiac myosin-binding protein C (MYBPC3). The amplified products were sequenced and compared with the standard sequence in the genBank so as to determine the potential mutation sites., Results: (1) 13 of the 36 FHCM patients (36.1%) harbored 3 different mutations in MYH7 gene: Arg663His in exon18, Glu924Lys in exon 23, and Ile736Thr in exon 20. Of the 50 SHCM patients, only 1 (2%) harbored MYH7 gene missence mutation: Ile736Thr located in exon 20. (2) TNNT2 was not identified in all SHCM patients and FHCM patients. (3) MYBPC3 was not identified in all SHCM patients. Four FHCM patients harbored 2 different mutations: Arg502Trp in exon 18 and Arg346fs in exon 13 respectively., Conclusion: MYH7 and MYBPC3 may be the dominant disease-causing genes in Chinese familial HCM patients; however the mutation rate of MYH7 and MYBPC3 genes is significantly lower in the SHCM patients compared with the FHCM patients. TNNT2 seems not the predominant disease-causing gene in all Chinese patients with HCM.

Phospholamban (PLB) is a prominent regulator of myocardial contractility and a reversible inhibitor of the cardiac sarcoplasmic reticulum Ca2+ ATPase activity. In normal cardiac muscles, phospholamban can be phosphorylated at distinct sites by various protein kinases and release its inhibition to sarcoplasmic reticulum Ca2+ ATPase. The studies of pedigrees have shown dilated cardiomyopathy (DCM) is related with mutation of PLB. The aim of present study is to investigate the relationship between mutation of PLB gene and DCM. Sixty patients with idiotic DCM were enrolled in present study. The clinical data were collected, including clinical symptoms, ECG and echocardiography. Peripheral blood samples of all these subjects were collected to extract genome DNA. The fragments of PLB gene were amplified by PCR and PCR fragment sequencing was performed to study weather mutation of phospholamban gene exists. phospholamban gene did not show any mutation in these patients. Most Chinese DCM patients may not be related with mutation of PLB gene.

Objective: To study the cardiac troponin T (TNNT2) gene mutation in Chinese patients with hypertrophic cardiomyopathy (HCM) and to analyze the correlation between the genotype and phenotype., Methods: Specimens of peripheral blood were collected from 71 unrelated Chinese probands with HCM, aged 40 +/- 18. The genome DNA was extracted. Single-strand conformation polymorphism gel analysis of the polymerase chain reaction-amplified products was conducted to search for mutations in the exons 8, 9, 10, 11, and 16 of the TNNT2 gene. Relevant clinical data were collected. One hundred normal persons, aged 44 +/- 14, were used as controls., Results: A missense mutation, K124N, in the exon 9 of the TNNT2 gene was identified in a 41-year-old female patient with HCM and failed to be detected in the 100 normal controls, which suggested the disease-causing mutation. The patient began to have the symptoms of chest distress and palpitation since the age of 38, presented moderate hypertrophy of the intraventricular septum, and did not have a family history of sudden cardiac death., Conclusion: A novel missense mutation of troponin T gene has been identified. Mutation in tail part of cardiac troponin T, essential for it's binding function, causes the disease of HCM. Correlative analysis confirms the genetic heterogeneity of the disease.

Objective: To evaluate the influence of the angiotensinogen(AGT) gene M235T variant on the prevalence and severity of hypertrophic cardiomyopathy(HCM)., Methods: The authors conducted a case-control study on 152 subjects, including 72 HCM patients and 80 normal controls. Polymerase chain reaction(PCR) combined with restriction fragment length polymorphism(RFLP) was used to detect the M235T variant of AGT gene. Interventricular septum thickness, left ventricular posterior wall thickness and apical wall thickness were measured by means of M-mode echocardiography under two-dimensional guidance in the parasternal long-axis plane and apical two- and four-chamber views., Results: (1) The genotype distributions of AGT gene in both groups were in agreement with Hardy-Weinberg equilibrium. (2) The genotype distributions of the M235T variant differed significantly in HCM patients and controls(chi-square=6.090 P<0.05). The frequencies of TT genotype and T235 allele in HCM patients were higher than did the patients in controls(TT genotype 0.63 vs 0.45 OR=2.037 95%CI 1.064-7.899 P<0.05 T235 allele 0.78 vs 0.64 OR=1.990 95%CI 1.197-3.308 P<0.01). (3)The patients with the TT genotype had significantly greater mean left ventricular maximal wall thickness than did the patients with the MM and MT genotypes [(19.1+/-4.8) mm vs(15.3+/-2.6)mm and(16.2+/-5.1)mm F=4.261 P<0.05]., Conclusion: The variant M235T of the AGT gene is significantly associated with HCM in this population. The genotype TT or allele T might be a genetic risk factor for the development and extent of hypertrophy in HCM patients.

Objective: To investigate the relationship between aldosterone synthase (CYP11B2) gene polymorphism and hypertrophic cardiomyopathy (HCM)., Methods: Fifteen HCM patients and 18 healthy subjects were enrolled in this study. Peripheral blood samples were collected from these subjects to exact genome DNA. PCR and Hae III restriction endonuclease digestion were employed to study -344C/T polymorphism of CYP11B2 gene., Results: CYP11B2 gene showed a significant difference in CT genotype distribution in HCM groups as compared with that in the control groups (P<0.05)., Conclusion: CT genotype of CYP11B2 gene may be one of factors responsible for the pathogenesis of HCM in a proportion of patients.

There are some human diseases associated with mitochondrial DNA genome defect. Now many studies think that: oxygen radical resulting from oxidative phosphorylation(OXPHOS) disorder caused by myocardium ischemia and the increased OXPHOS induction damage mitochondrial DNA. Chronic damage accumulations lead to mitochondrial DNA deletion or point mutation in the end which show mitochondrial DNA 5.0 kb or 7.4 kb deletion and point mutation at position C15452A in the cytochrome b gene; the conservative sequence mutation of tRNA gene such as A4300G, C4320T point mutation in the tRNA Ilegene, A3243G point mutation in the tRNA leu gene etc result in defective contractile proteins whose persistent and inefficient contraction may increase the myocardium's metabolic demands for ATP and leads to cardiac hypertrophy. In this article, we review the study on the association of mitochondrial DNA mutation with ischemic cardiomyopathy and hypertrophic cardiomyopathy.