Searching for genetic determinants for left ventricular non-compaction.

Background: Left ventricular non-compaction (LVNC) is still a pathology around which there are numerous controversies regarding the criteria for its diagnosis, presentation, prognosis, and even classification into the appropriate group of diseases. So far, about 190 genes in which mutations may be associated with LVNC have been described, and in each of them, several to several dozen different loci have been discovered. We decided to analyze the frequency of single nucleotide variants (SNVs) in correlation to Petersen's criteria. Methods: We retrospectively analyzed the results of cardiac magnetic resonance (CMR) studies. Twenty-three patients who met Petersen's criteria agreed to participate in the research and take blood samples for genetic testing. Next, we prospectively included 24 volunteers who did not meet Petersen's criteria. Petersen's criteria were complied with ratio of non-compacted to compacted myocardium (NC/C) ≥2.3. A total of 47 DNA samples were analyzed based on the selected regions of the following genes: ß-myosin heavy chain (MYH7), α-cardiac actin (ACTC1), cardiac troponin T (TNNT2), myosin binding protein-C (MYBPC3), LIM-domain binding protein 3 (LBD3), and taffazin (TAZ). Results: In total, 248 substitutions in exons and introns were obtained for all analyzed samples. No statistically significant differences were detected between the mentioned groups. No significant difference in either downward or upward trends in the number of substitutions in relation to the increasing trabeculation is observed. We indicated differences in the occurrence of the studied SNVs between groups, especially for rs8037241 (3'UTR region of ACTC1) and rs2675686 (LDB3), but they also did not show statistical significance. Although we did not find a significant correlation between the co-occurrence of individual mutations with LVNC, it is worth noting that the presence of one of the four mutations in the range rs8037241 (ACTC1 3'UTR), rs3729998 (TNNT2e. 12), and rs727503240 (MYH7e. 39) increases the risk of LVNC more than 4 times. An inverse association between the number of SNVs and the meeting the Petersen's criteria was demonstrated for studied LDB3 region and rs397516254 in exon 39 of the MYH7 gene. Conclusions: To our knowledge, no studies have been published comparing the prevalence of selected SNVs in a group of healthy subjects and in a group meeting the Petersen criteria for LVNC. Among both completely healthy individuals who did not meet the Petersen criteria for LVNC as well as those with symptoms who met these criteria we found a similar incidence of SNVs in the ACTC1, TNNT2, LDB3 and MYH7 genes segments analyzed. Further studies are required to confirm or exclude "potentially protective" SNV in the 39th exon of MYH7 (rs397516254) and the role of co-occurrence of individual SNVs in rs8037241 (ACTC1 3'UTR), rs3729998 (TNNT2), and rs727503240 (MYH7) for the increase of the risk of LVNC.

MYH7 mutation is associated with mitral valve leaflet elongation in patients with obstructive hypertrophic cardiomyopathy.

Mitral valve (MV) leaflet elongation is recognized as a primary phenotypic expression of hypertrophic cardiomyopathy (HCM) that contributes to obstruction. This study investigates the correlation between MV length and genotype mutations in the two predominant genes, myosin-binding protein C (MYBPC3), and the ß-myosin heavy chain (MYH7) in patients with obstructive HCM (OHCM). Among the 402 OHCM patients, there were likely pathogenic or pathogenic variations in MYH7 (n = 94) and MYBPC3 (n = 76), along with a mutation-negative group (n = 212). Compared to genotype-negative patients, genotype-positive individuals exhibited elongated MV length, thicker interventricular septum, and increased instances of late gadolinium enhancement. Notably, MYH7 mutations were associated with a more severe disease trajectory than MYBPC3 mutations. After adjusting for potential confounders, multivariate linear regression analysis revealed that MYH7 gene mutations and left ventricular volume were independently associated with MV leaflet elongation. The study indicates that mutations in MYH7 and hemodynamics factors are significant risk factors for elongated MV leaflet. Consequently, regular assessment of MV length, especially in patients with MYH7 mutation and enlarged LV volume, is crucial for timely preoperative strategic planning and improved prognosis.

Novel MYH7 Variant in the Neonate of a Mother with Gestational Diabetes Mellitus Showing Left Ventricular Hypertrophy and Noncompaction.

BACKGROUND: Left ventricular hypertrophy (LVH) is a well-recognized cardiac dysfunction in infants of mothers with gestational diabetes mellitus (GDM). Left ventricular noncompaction (LVNC) is a cardiomyopathy that is morphologically characterized by numerous prominent trabeculations and deep intertrabecular recesses on cardiovascular imaging. However, there have been no case reports on neonates of mothers with GDM showing LVH and LVNC. CASE PRESENTATION: A patient, with LVH of a mother with GDM, was delivered at 36 weeks of gestation. Prominent trabeculations in the LV, suggesting LVNC, instead of LVH, were apparent 1 week after birth. A heterozygous deletion variant in the MYH7 gene (NM_000257.4: c.1090T>C, p.Phe364Leu) was discovered through genetic testing using a cardiomyopathy-associated gene panel in the patient and his father and the older brother who had LVNC. The patient is now 5 years old and does not have major cardiac events, although LVNC persisted. This is the first case of LVH secondary to a mother with GDM and LVNC with a novel variant in the MYH7 gene. CONCLUSION: Genetic testing should be conducted to obtain an accurate outcome and medical care in a patient with LVH and subsequently prominent hypertrabeculation in the LV.

[Phenotype and genotype characteristics of children with cardiomyopathy associated with MYH7 gene mutation: a retrospective analysis]. / MYH7åŸºå› å˜å¼‚ç›¸å ³å„¿ç«¥å¿ƒè‚Œç— è¡¨åž‹ä¸ŽåŸºå› åž‹ç‰¹ç‚¹çš„å›žé¡¾æ€§åˆ†æž.

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.

[Recent research on childhood hypertrophic cardiomyopathy caused by MYH7 gene mutations]. / MYH7åŸºå› çªå˜è‡´å„¿ç«¥è‚¥åŽšåž‹å¿ƒè‚Œç— çš„ç ”ç©¶è¿›å±•.

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.

Successful pregnancy and delivery in a young-onset hypertrophic cardiomyopathy patient with a novel doublet-base substitution in the MYH7 gene.

Herein, we report the case of a young-onset female hypertrophic cardiomyopathy (HCM) patient with severe left ventricular outflow tract obstruction who had a family history of premature sudden cardiac death. Despite the severe HCM phenotype, the patient was successfully managed by low-dose bisoprolol during two peripartum periods after a percutaneous transluminal septal myocardial ablation.We performed whole-genome sequencing analysis and found a novel doublet-base substitution (DBS) in the MYH7 gene (c.2608_2609delinsTT, p.R870F) in this patient. Her children were also genetically tested after careful genetic counselling to their parents, and one of her children at 1-year-old with left ventricular hypertrophy was found to have the same gene mutation. The location of the DBS in a functionally important domain and the inheritance of the same mutation in the offspring with the HCM phenotype suggested that this mutation in the MYH7 gene was responsible for the severe HCM phenotype. Proactive genetic testing would provide beneficial information for appropriate follow-up and initiation of therapy in children with possibly pathogenic gene mutations; however, revisions of genetic counselling may be considered according to their growth. Learning objective: Hypertrophic cardiomyopathy (HCM) patients with severe left ventricular outflow tract obstruction are at a high risk of hemodynamic deterioration during pregnancy. Preceding myocardial ablation therapy and a careful medical management during peripartum period may enable safe pregnancy and delivery in severe obstructive HCM patients. A novel doublet-base substitution in the MYH7 gene (c.2608_2609delinsTT, p.R870F) was found as a likely pathogenic mutation of young-onset severe HCM.

Left ventricular non-compaction cardiomyopathy: restrictive subtype with MYH7 gene mutation.

Left ventricular non-compaction is a very rare, still unclassified congenital cardiomyopathy. Nine distinct subtypes of functional and anatomical left ventricular non-compaction have been identified. Studies on the prognosis and mortality of subtypes are ongoing. Our study presented the first restrictive subtype left ventricular non-compaction case with family history and MYH7 gene mutation.

Left ventricular noncompaction associated with a pathogenic mutation in the MYH7 gene: Known mutation, different phenotype.

Left ventricular noncompaction (LVNC) is a genetically heterogeneous cardiomyopathy, with familial and sporadic forms, but genetic testing only identifies a pathogenic mutation in a minority of cases. The main complications are heart failure, embolism and dysrhythmias. Herein we report a familial case of LVNC associated with a mutation in the MYH7 gene and review the literature regarding controversies in LVNC. A 50-year-old woman was referred to the cardiology clinic for palpitations. She underwent echocardiography and cardiac magnetic resonance imaging that revealed mild left ventricular systolic dysfunction and LVNC criteria. She had several episodes of non-sustained ventricular tachycardia and received an implantable cardioverter-defibrillator (ICD). Genetic testing revealed the c.1003G>C (p.Ala335Pro) mutation in the MYH7 gene. Familial screening showed clear genotype-phenotype cosegregation, which provided strong evidence for the pathogenic role of this mutation. To the best of our knowledge, this is the first report of LVNC associated with the p.Ala335Pro mutation in the MYH7 gene. This mutation has been described in hypertrophic cardiomyopathy, suggesting that the same pathogenic sarcomere mutation may be associated with different cardiomyopathies. This case also highlights the current difficulties regarding decisions on ICD implantation for primary prevention of sudden cardiac death in LVNC.

Variants in MHY7 Gene Cause Arrhythmogenic Cardiomyopathy.

BACKGROUND: Arrhythmogenic Cardiomyopathy (ACM) is a disease of the cardiac muscle, characterized by frequent ventricular arrhythmias and functional/ structural abnormalities, mainly of the right ventricle. To date, 20 different genes have been associated with ACM and the majority of them encode for desmosomal proteins. In this study, we describe the characterization of two novel variants in MHY7 gene, segregating in two ACM families. MYH7 encodes for myosin heavy chain ß (MHC-ß) isoform, involved in cardiac muscle contractility. METHOD AND RESULTS: In family A, the autopsy revealed ACM with biventricular involvement in both the proband and his father. In family B, the proband had been diagnosed as affected by ACM and implanted with implantable cardioverter defibrillator (ICD), due to ECG evidence of monomorphic ventricular tachycardia after syncope. After clinical evaluation, a molecular diagnosis was performed using a NGS custom panel. The two novel variants identified predicted damaging, located in a highly conserved domain: c. 2630T>C is not described while c.2609G>A has a frequency of 0.00000398. In silico analyses evaluated the docking characteristics between proteins using the Haddock2.2 webserver. CONCLUSIONS: Our results reveal two variants in sarcomeric genes to be the molecular cause of ACM, further increasing the genetic heterogeneity of the disease; in fact, sarcomeric variants are usually associated with HCM phenotype. Studies on the role of sarcomere genes in the pathogenesis of ACM are surely recommended in those ACM patients negative for desmosomal mutation screening.

MYH7-related disorders in two Bulgarian families: Novel variants in the same region associated with different clinical manifestation and disease penetrance.

Pathogenic variants in MYH7 cause a wide range of cardiac and skeletal muscle diseases with childhood or adult onset. These include dilated and/or hypertrophic cardiomyopathy, left ventricular non-compaction cardiomyopathy, congenital myopathies with multi-minicores and myofiber type disproportion, myosin storage myopathy, Laing distal myopathy and others (scapulo-peroneal or limb-girdle muscle forms). Here we report the results from molecular genetic analyses (NGS and Sanger sequencing) of 4 patients in two families with variable neuromuscular phenotypes with or without cardiac involvement. Interestingly, variants in MYH7 gene appeared to be the cause in all the cases. A novel nonsense variant c.5746C>T, p.(Gln1916Ter) was found in the patient in Family 1 who deceased at the age of 2 years 4 months with the clinical diagnosis of dilated cardiomyopathy, whose father died before the age of 40 years, due to cardiac failure with clinical diagnosis of suspected limb-girdle muscular dystrophy. A splice acceptor variant c.5560-2A>C in MYH7 was detected in the second proband and her sister, with late onset distal myopathy without cardiac involvement. These different phenotypes (muscular involvement with severe cardiomyopathy and pure late onset neuromuscular phenotype without heart involvement) may result from novel MYH7 variants, which most probably impact the LMM (light meromyosin) domain's function of the mature protein.

Laing early-onset distal myopathy with subsarcolemmal hyaline bodies caused by a novel variant in the MYH7 gene.

Myopathies caused by MYH7 gene mutations are clinically and pathologically heterogeneous and, until recently, difficult to diagnose. The availability of NGS panels for hereditary neuromuscular diseases changed our insight regarding their frequency and allowed a better perception of the different phenotypes and morphological abnormalities associated. We present a male Portuguese patient with the classical phenotype of Laing early-onset distal myopathy (MPD1) beginning at 6 years of age, very slowly progressive, and with a mild to moderate impact on daily life by the age of 56. Muscle biopsy showed a myopathic pattern with hyaline bodies and cores. The NGS panel for structural myopathies identified a novel missense heterozygous variant, c.T4652C (p.Leu1551Pro), in the exon 34 of the MYH7 gene.

[A case of Japanese Laing type distal myopathy with a mutation in MYH7 gene].

A 67-year-old man developed weakness and atrophy of the anterior compartment of the lower leg at age 53 years, followed by weakness of proximal muscles of the upper limb. His father had difficulties in walking in his thirties and died of heart disease at age 45 years. He also had mild respiratory weakness without cardiac involvement. Muscle histology showed spheroid or cytoplasmic bodies-like inclusions with moth-eaten appearance and irregular intramyofibrillar network. Electron microscopy revealed abnormally thickened and disorganized Z lines (Z line streaming) between the surrounding myofibrils and electron-dense globular deposits. These pathological findings apparently suggested myofibrillar myopathy. However, genetic analysis revealed a mutation (c.5566G>A, p.E1856K) in MYH7 gene, that is responsible for Laing-type distal myopathy (LDM). This mutation was previously reported in a study from Austria. This is the first report of LDM in the Japanese population .

De novo exonic mutation in MYH7 gene leading to exon skipping in a patient with early onset muscular weakness and fiber-type disproportion.

Here we report on a case of MYH7-related myopathy in a boy with early onset of muscular weakness and delayed motor development in infancy. His most affected muscles were neck extensors showing a dropped head sign, proximal muscles of lower limbs with positive Gower's sign, and trunk muscles. Brain and spinal cord MRI scans, echocardiography, and laboratory analyses including creatine kinase and lactate did not reveal any abnormalities. Muscle histopathology showed fiber-type disproportion. Whole exome sequencing of the parents-offspring trio revealed a novel de novo c.5655G>A p.(Ala1885=) synonymous substitution of the last nucleotide in exon 38 of the MYH7 gene. Further RNA investigations proved the skipping of exon 38 (p.1854_1885del). This is a first report of an exon-skipping mutation in the MYH7 gene causing myopathy. This report broadens both the phenotypic and genotypic spectra of MYH7-related myopathies.

Familial ebstein anomaly, left ventricular hypertrabeculation, and ventricular septal defect associated with a MYH7 mutation.

Ebstein anomaly is a rare congenital heart defect that most often occurs sporadically within a kindred. Familial cases, although reported, are uncommon. At this time, the genetic etiology of Ebstein anomaly is not fully elucidated. Here, we describe clinical and molecular investigations of a rare case of familial Ebstein anomaly in association with a likely pathogenic mutation of the MYH7 gene. The severity of presentation varies, and Ebstein anomaly can be observed in association with such other heart defects as ventricular septal defect and left ventricular (LV) hypertrabeculation, as seen in our family of study. In our family of study, the 31-year-old father and four of his children have been diagnosed with Ebstein anomaly. Genetic testing revealed that the father was heterozygous for the Glu1220del variant detected in exon 27 of the MYH7 gene. The MYH7 gene encodes the ß-myosin heavy chain and is expressed in cardiac muscle. DNA sequencing of three of his affected children confirmed that they carried the same variant while the fourth affected child was not available for testing. This is the first report of familial Ebstein anomaly associated with the Glu1220del mutation of the MYH7 gene. The mutation segregates with disease in a family with autosomal dominant transmission of congenital heart defects including Ebstein anomaly and other associated cardiovascular defects including LV hypertrabeculation and ventricular septal defect.

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.