Cardiac Anderson-Fabry disease: Lessons from a 25-year-follow up

Sarcomeric hypertrophic cardiomyopathy (HCM) is the most common genetic cause of unexplained left ventricular hypertrophy and has no specific treatment. Anderson-Fabry disease (AFD) is rare and usually multisystemic, but occasionally expresses clinically as a predominantly cardiac phenotype mimicking HCM. We describe an illustrative case of a patient followed regularly for 25 years with a diagnosis of familial HCM and no identified sarcomeric mutations. Next-generation sequencing analysis identified a novel pathogenic mutation in the GLA gene, leading to a diagnosis of previously unknown multisystemic AFD, with consequent implications for the patient's treatment and prognosis and familial screening.     

Screening for Fabry disease in patients with left ventricular noncompaction

Introduction and AimIt is unclear whether left ventricular noncompaction (LVNC) is a distinct cardiomyopathy or a morphologic manifestation of different cardiomyopathies. We previously reported a case of LVNC in a Fabry disease (FD) patient, but it remains to be clarified whether LVNC is a cardiac manifestation of FD, a coincidental finding or an overdiagnosis, which has major therapeutic implications. This study aims to determine the prevalence of FD among patients with LVNC.MethodsWe performed a retrospective study including all patients diagnosed with LVNC in eight hospital centers. Diagnosis of LVNC was based on at least one echocardiographic or cardiac magnetic resonance criterion. FD screening was performed by combined enzyme and genetic testing.ResultsThe study included 78 patients diagnosed with LVNC based on the Jenni (84.6%), Stöllberger (46.2%), Chin (21.8%), Petersen (83.8%) and Jacquier (16.2%) criteria. Left ventricular systolic dysfunction was present in 48.7%. Heart failure was found in 60.3%, ventricular dysrhythmias in 21.6% and embolic events in 11.5%. FD screening found no additional cases among patients with LVNC, besides the previously described case.ConclusionNo additional FD cases were found among patients with LVNC, which argues against the hypothesis that LVNC is a cardiac manifestation of FD.     

Identification of a novel titin-cap/telethonin mutation in a Portuguese family with hypertrophic cardiomyopathy

Introduction and objectivesHypertrophic cardiomyopathy (HCM) is a genetically and phenotypically heterogeneous disease; there is still a large proportion of patients with no identified disease-causing mutation. Although the majority of mutations are found in the MYH7 and MYBPC3 genes, mutations in Z-disk-associated proteins have also been linked to HCM.MethodsWe assessed a small family with HCM based on family history, physical examination, 12-lead ECG, echocardiogram and magnetic resonance imaging. After exclusion of mutations in eleven HCM disease genes, we performed direct sequencing of the TCAP gene encoding the Z-disk protein titin-cap (also known as telethonin).ResultsWe present a novel TCAP mutation in a small family affected by HCM. The identified p.C57W mutation showed a very low population frequency, as well as high conservation across species. All of the bioinformatic prediction tools used considered this mutation to be damaging/deleterious. Family members were screened for this new mutation and a co-segregation pattern was detected. Both affected members of this family presented with late-onset HCM, moderate asymmetric left ventricular hypertrophy, atrial fibrillation and heart failure with preserved ejection fraction and low risk of sudden cardiac death.ConclusionsWe present evidence supporting the classification of the TCAP p.C57W mutation, encoding the Z-disk protein titin-cap/telethonin as a new likely pathogenic variant of hypertrophic cardiomyopathy, with a specific phenotype in the family under analysis.     

Hypertrophic cardiomyopathy: infrequent mutation of the cardiac beta-myosin heavy-chain gene

The aim of this study was to identify mutations in the cardiac heavy-chain beta-myosin gene (MYH7b) in a group of Spanish patients with hypertrophic cardiomyopathy. The study included 36 families with at least one member who had hypertrophic cardiomyopathy. DNA from exons 3 to 24 of the MYH7b gene was sequenced. Two mutations were identified: Arg858Cys and Met515Val. They occurred in two families, one of which was of Moroccan origin. This corresponds to a MYH7b gene mutation frequency of less than 5%. In contrast to findings in other Caucasian populations, MYH7b gene mutation occurred infrequently in this group of Spanish families with hypertrophic cardiomyopathy.     

Histopathological evidence of Fabry disease in a female patient with left ventricular noncompaction

Fabry disease is a rare X-linked lysosomal storage disorder caused by mutations in the alpha-galactosidase gene. The most frequent cardiac presentation of Fabry disease is cardiomyopathy characterized by left ventricular (LV) hypertrophy, usually concentric.Heart disease in affected females tends to be clinically recognized later than in males and cardiac complications are the most frequently reported cause of death in females with Fabry disease. There are few data regarding the association between Fabry disease and LV noncompaction. We report a case of a 30-year-old asymptomatic woman, heterozygous for a nonsense alpha-galactosidase gene mutation (p.R220X), who presented LV noncompaction on cardiac magnetic resonance imaging, without LV wall hypertrophy. Histopathological examination of myocardial fragments showed marked deposition of glycosphingolipids in cardiomyocytes, confirming the diagnosis of Fabry cardiomyopathy. Based on this finding, the patient was proposed for enzyme replacement therapy. This case illustrates the role of endomyocardial biopsy in the clarification of doubtful or atypical findings related to cardiac Fabry disease, even in heterozygous women, and corroborates the contention that Fabry disease should be included in the differential diagnosis of LV hypertrabeculation/noncompaction.     

Familial hypertrophic cardiomyopathy associated with a novel missense mutation affecting the ATP-binding region of the cardiac beta-myosin heavy chain.

Mutations in the cardiac beta -myosin heavy chain gene (MYH7), and other genes encoding cardiac sarcomere proteins may cause familial hypertrophic cardiomyopathy (F-HCM), an autosomal dominant disease, characterized by myocardial hypertrophy. We analysed the MYH7 gene in three generations of a family with one borderline and four clinically verified cases of hypertrophic cardiomyopathy, and identified a mutation in exon 7 changing the 190 arginine residue into a threonine residue. The mutation is located in the ATP-binding region of the myosin head and alters the charge in the F-helix close to the phosphate-binding P-loop. The mutation may thus interfere with the coupling between ATP-hydrolysis and the transition into mechanical energy. In conclusion, the novel Arg190Thr mutation in exon 7 of the MYH7 gene is associated with the development of symptomatic myocardial hypertrophy in adults.     

β肌球蛋白重链基因Asn391Thr突变导致家族性肥厚型心肌病的基因型与临床表型分析

目的研究家族性肥厚型心肌病（HCM）致病基因突变位点,分析基因型与临床表型的联系。方法利用靶向捕获加二代测序,对1个HCM家系的先证者进行26个致病基因的筛查。二代测序发现的突变,利用双脱氧末端终止法测序进行验证,并对家族中其他成员进行该突变位点的筛查,并分析其临床表型特点。结果遗传筛查发现先证者携带β肌球蛋白重链基因（MYH7）．c．1172A〉C（Asn391Thr）突变,该突变位于MYH7基因第12号外显子,导致β肌球蛋白重链的第391位氨基酸残基由天冬酰胺变为苏氨酸。该家系中接受调查的22例对象中8例携带MYH7基因Asn391Thr突变,其中6例患者均携带该突变,突变与疾病呈共分离,且在307名对照者中没有检出。携带者中有3例出现呼吸困难、心悸、胸痛、黑噱等心功能不全表现,所有患者发病年龄均小于40岁,其中Ⅱ9小于8岁（见图1）。家系中有4人早逝（〈50岁）,其中3人确诊为HCM。结论MYH7基因Asn391Thr错义突变为HCM的一个恶性致病突变,携带该突变的患者应进行较积极的治疗和猝死预防。     

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。     

MYH9 related disease: A novel missense Ala95Asp mutation of the MYH9 gene

MYH9-related disease (MYH9-RD) is a rare autosomal dominant disorder caused by mutations in MYH9, the gene encoding the heavy chain of non-muscle myosin IIA. Patients present with congenital macrothrombocytopenia and inclusion bodies in neutrophils and might develop sensorineural deafness, presenile cataract, and/or progressive nephritis leading to end-stage renal failure. In a family with eight individuals suffering from macrothrombocytopenia and hearing impairment we identified a novel c.Ala95Asp mutation. Affecting the motor domain of the protein, the mutation is likely to be associated with a severe phenotype. Therefore, this family should be carefully monitored to follow-up the renal status even though the affected members do not seem to be at risk of early kidney disease.     

Familial hypertrophic cardiomyopathy owing to double heterozygosity for a 403Arg→ Trp mutation in exon 13 of the MYH7 gene and a novel mutation, 453Arg→ His,in exon 14 of the MYH7 gene: A case report

An unusual clinical history of a 23-year-old male proband with obstructive hypertrophic cardiomyopathy associated with a rare genotype is presented. Genetic analysis of the proband found evidence for two distinct mutations of the MYH7 gene (the gene coding for the beta-myosin heavy chain): 403Arg→ Trp in exon 13 and a novel mutation, 453Arg→ His, in exon 14. A heterozygous site mutation was identified in exon 13 in the proband’s father but no mutation site was found in his mother. Thus, the novel mutation in exon 14 is a de novo mutation.     

A de novo Mutation of the Beta Cardiac Myosin Heavy Chain Gene in an Infantile Restrictive Cardiomyopathy

Here we report the first pediatric case of restrictive cardiomyopathy secondary to a de novo mutation in the cardiac myosin heavy chain gene MYH7. The clinical course is characterized by an early onset of disease, mild hypertrophy of the left ventricle and a very short evolution to death. Because of the location of the mutation in the hinge region between the rod part and the globular head of the myosin molecule, it is possible that restrictive cardiomyopathy resulted from an impairment of flexion/extension of myosin heads during the contraction/relaxation cycle.     

Implantação de dispositivos de ressincronização e/ou desfibrilhação em doentes com insuficiência cardíaca: dados da vida real ‐ o Estudo Síncrone

Introduction

The aim of this study was to document clinical practice in Portugal regarding the use of electronic cardiac devices in patients with heart failure (HF) and reduced left ventricular ejection fraction (LVEF).

Characteristics of the beta myosin heavy chain gene Ala26Val mutation in a Chinese family with hypertrophic cardiomyopathy

BACKGROUND: Genotype-phenotype studies have suggested that some mutations of genes encoding various components of the cardiac sarcomere cause hypertrophic cardiomyopathy (HCM) and are associated with the prognosis of patients with HCM. The aims of this study were to investigate the gene mutations of exons in the cardiac beta myosin heavy chain (MYH7) gene, the troponin T (TNNT2) gene, and the brain natriuretic peptide (BNP) gene, as well as to assess the effect of these mutations on the clinical features of Chinese patients with HCM. METHODS: Five unrelated Chinese families with HCM were studied. Exons 3 and 18 in the MYH7 gene, exon 9 in the TNNT2 gene, and all three exons in the BNP gene were screened with the polymerase chain reaction (PCR) for genomic DNA amplification. Further study included purification of PCR products and direct sequencing of PCR fragments by fluorescent end labeling. RESULTS: A C-to-T transition in codon 26 of exon 3 in the MYH7 gene was found in one family (including four patients and five carriers), resulting in an amino acid substitution of valine (Val) for alanine (Ala). The Ala26Val mutation was of incomplete dominance (penetrance 44%). This mutation was not seen in the other four families or in the control group. Moreover, the association between the gene mutations of exon 18 in MYH7, of exon 9 of TNNT2, and of all three exons in BNP and HCM was not found in the populations we studied. CONCLUSIONS: The missense mutation Ala26Val found in this one Chinese family was associated with a mild phenotype of HCM. The genetic and phenotypic heterogeneity of HCM exists in the Chinese population. It suggests that genetic and environmental factors may be involved in the pathogenesis of HCM.     

Natural history and familial characteristics of isolated left ventricular non-compaction.

AIMS: Non-compaction of the left ventricle (LVNC) is a disorder of endomyocardial morphogenesis that results in multiple trabeculations in the left ventricular myocardium. The current literature suggests that LVNC in adults is rare and associated with a poor prognosis. Given that the disorder is present at birth and that several studies have reported asymptomatic familial disease in some patients, we hypothesized that there is a long pre-clinical phase of the disease. The aim of this study was to define the prognosis and familial incidence of LVNC. METHODS AND RESULTS: This study cohort comprised 45 patients (mean age at diagnosis 37 years) consecutively identified at a referral centre for cardiomyopathy over a 10-year period. Twenty-eight patients (62%) had dyspnoea at presentation; 41 (91%) an abnormal ECG; and 30 (66%) left ventricular dilatation and impaired systolic function. Nine patients (20%) had non-sustained ventricular tachycardia on 24 h Holter monitoring. Mean survival from death or transplantation was 97% at 46 months. There were three thromboembolic events in two patients (4%). On systematic family screening, 8 of 32 (25%) asymptomatic relatives had a range of echocardiographic abnormalities, including LVNC, LVNC with impaired systolic function, and left ventricular enlargement without LVNC. CONCLUSION: This study demonstrates that LVNC is associated with a better prognosis than previously reported. In patients with familial disease, relatives may have features consistent with dilated cardiomyopathy rather than LVNC.     

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.     

Mutation screening in dilated cardiomyopathy: prominent role of the beta myosin heavy chain gene.

AIMS: Familial dilated cardiomyopathy (FDCM) is associated with mutations in more than 10 genes, but genes mutation frequencies and associated clinical features remain largely unknown. Here, we performed a mutation analysis of four genes involved in FDCM in a population of idiopathic DCM. METHODS AND RESULTS: A SSCP and sequencing mutation screening of all the exons coding for beta myosin heavy chain (MYH7 gene), cardiac T troponin (TNNT2 gene), phospholamban (PLN gene), and the cardio-specific exon of metavinculin (VCL gene) were performed in 96 independent patients (54 familial and 42 sporadic). It led to the identification of eight heterozygous mutations, seven new ones in MYH7, and the already described R141W mutation in TNNT2. MYH7 mutations (in five familial and two sporadic cases) substitute residues located either in the head (I201T, T412N, A550V) or tail domains (T1019N, R1193S, E1426K, R1634S) of the protein. DCM was not associated with skeletal myopathy or conduction defects in any patients. Contrasting clinical features were observed between MYH7 and TNNT2 mutations carriers. In MYH7 vs. TNNT2, mean age at diagnosis was late (P<0.03), penetrance was incomplete in adults (56 vs. 100%), and mean age at major cardiac event was higher (P<0.04). CONCLUSION: We have identified seven mutations in MYH7, one in TNNT2, and none in PLN or in the VCL cardio-specific exon. MYH7 appears as the most frequently mutated gene in our FDCM population (approximately 10%), and mutation carriers present with delayed onset, in contrast to TNNT2.     

国人肥厚型心肌病患者肌球蛋白结合蛋白C基因Gly507 Arg和Pro1208fs突变的不同临床表型

目的 研究中国人肥厚型心肌病的致病基因,阐述基因型-表型的关系.方法 对21例无血缘关系的肥厚型心肌病先证者进行心脏型肌球蛋白结合蛋白C基因(cMYBPC3)突变筛查,利用聚合酶链反应(PCR)扩增其功能Ⅸ的外显子片段,双脱氧末端终止法测序.家系资料调查包括临床表现、体格检查、心脏超声和心电图.结果 在2例先证者中发现基因突变.其中H12为家族性肥厚型心肌病的先证者,为cMYBPC3基因第32号外显子Pro1208fs突变,即在人类基因组第21078处发生了碱基C的缺失.H19为散发肥厚型心肌病患者,在cMYBPC3基因第17号外显子发现Gly507Arg突变,即在人类基因组第10 966处发生了碱基G→A互换,使甘氨酸变为精氨酸.H12发病年龄较晚,临床表现轻微.H19为24岁青年男性,超声心动图示肥厚累及部位广泛,室壁较厚,舒张功能减退明显,左心房明显增大.80例正常对照未发现异常.结论 cMYBPC3基因Gly507Arg和Pro1208fs突变可能致国人肥厚型心肌病.     

国人肥厚型心肌病患者肌球蛋白结合蛋白C基因Gly507 Arg和Pro1208fs突变的不同临床表型

目的 研究中国人肥厚型心肌病的致病基因,阐述基因型-表型的关系.方法 对21例无血缘关系的肥厚型心肌病先证者进行心脏型肌球蛋白结合蛋白C基因(cMYBPC3)突变筛查,利用聚合酶链反应(PCR)扩增其功能Ⅸ的外显子片段,双脱氧末端终止法测序.家系资料调查包括临床表现、体格检查、心脏超声和心电图.结果 在2例先证者中发现基因突变.其中H12为家族性肥厚型心肌病的先证者,为cMYBPC3基因第32号外显子Pro1208fs突变,即在人类基因组第21078处发生了碱基C的缺失.H19为散发肥厚型心肌病患者,在cMYBPC3基因第17号外显子发现Gly507Arg突变,即在人类基因组第10 966处发生了碱基G→A互换,使甘氨酸变为精氨酸.H12发病年龄较晚,临床表现轻微.H19为24岁青年男性,超声心动图示肥厚累及部位广泛,室壁较厚,舒张功能减退明显,左心房明显增大.80例正常对照未发现异常.结论 cMYBPC3基因Gly507Arg和Pro1208fs突变可能致国人肥厚型心肌病.     

Left ventricular non‐compaction: Prevalence in congenital heart disease

Introduction

Left ventricular non-compaction cardiomyopathy (LVNC) is a rare cardiomyopathy, originally described as an isolated disease without other structural cardiac abnormalities. The aim of this study was to explore the prevalence of LVNC among adults with different types of congenital heart disease.

Methods

From our databases we identified adults with congenital heart disease who fulfilled diagnostic criteria for LVNC. We report frequencies of associated congenital cardiac defects and the prevalence of LVNC among patients with different congenital heart defects.

Results

From a total of 202 patients with LVNC, 24 patients (12%; mean age 32 ± 11 years, 19 males) had additional congenital cardiac defects. Associated defects were left ventricular outflow tract abnormalities in 11 patients (46%), including 7 uni- or bicuspid aortic valves; two aortic coarctations; one diffuse aortic hypoplasia and one subaortic stenosis, Ebstein anomaly in 6 patients (25%), tetralogy of Fallot in two (8%), and double outlet right ventricle in one patient (4%). In our cohort, the prevalence of LVNC was highest among patients with Ebstein anomaly (6/40, 15%), followed by aortic coarctation (2/60, 3%), tetralogy of Fallot (3/129, 2%) and uni- or bicuspid aortic valves (7/963, 1%).

Conclusion

In adults, various forms of congenital heart disease are associated with LVNC, particularly stenotic lesions of the left ventricular outflow tract, Ebstein anomaly, and tetralogy of Fallot. In the future, studying these patients in more depth may provide a better understanding of the interplay between genetic and hemodynamic factors that lead to the phenotype of LVNC.     

Clinical profile in arrhythmogenic cardiomyopathy and a recessive plakophilin-2 gene mutation

ObjectiveArrhythmogenic cardiomyopathy (ACM) is not an uncommon cause of cardiac morbidity in Kashmir valley. This study was designed to document various clinical features and to sequence exons 11 and 12 of plakophilin 2 (PKP2) gene in these patients.MethodsACM patients who attended cardiology outpatient department of our institute from January 2014 to April 2015 were included in the study. Their records were reviewed. Controls were randomly selected, who had no history or family history of cardiac illness and had a normal cardiac examination. A blood sample was also taken from both the groups for sequencing of exon 11 and 12 of PKP2 gene. ACM patients were followed up until July 2016.ResultsEleven ACM patients and seven controls were included in the study. Most common mode of presentation was ventricular tachycardia (VT). Two patients had left ventricular (LV) systolic dysfunction. One patient had a splice site mutation in exon 12 of PKP2 gene and one patient died during follow-up. One of the controls had an intronic variation that has no pathogenic significance vis-à-vis ACM.ConclusionOur study describes various clinical parameters in ACM patients and a recessive plakophilin 2 mutation after a limited PKP2 gene sequencing.