Recent research on childhood hypertrophic cardiomyopathy caused by MYH7 gene mutations / 中国当代儿科杂志

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.

Phenotype and genotype characteristics of children with cardiomyopathy associated with MYH7 gene mutation: a retrospective analysis / 中国当代儿科杂志

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.

Genes frequently associated with sudden death in primary hypertrophic cardiomyopathy / Genes frecuentemente asociados con muerte súbita en miocardiopatía hipertrófica primaria

Abstract Hypertrophic cardiomyopathy (HCM) is characterized by left ventricular hypertrophy without apparent cardiac justification. Sudden cardiac death may be the first manifestation of the disease. It occurs mainly in adulthood and can be seen in childhood and adolescence where genetic origin predominates. Primary HCM (“familial”) is inherited in an autosomal dominant pattern in the 25 subtypes informed in Online Mendelian Inheritance in Man. The proteins encoded by the mutated genes are part of the sarcomere in the cardiac cells, being the thick filament the most frequently affected, with the worst prognosis. In the present article, we describe the Mendelian inheritance of the disease and the two most associated genes with sudden death: MYBPC3 and MYH7.

Resumen La miocardiopatía hipertrófica (MCH) es el aumento de grosor de la pared ventricular izquierda no relacionada con otras alteraciones cardíacas. Es una enfermedad que puede presentar como primera manifestación clínica la muerte súbita y de ahí su relevancia clínica. Aunque se presenta sobre todo en la edad adulta, puede aparecer durante la infancia y adolescencia, en las que predominan los casos de origen hereditario. La MCH primaria, de causa genética, muestra en particular un patrón de herencia autosómico dominante en los 25 subtipos reconocidos en OMIM (Online Mendelian Inheritance in Man). Las proteínas codificadas por los genes mutantes forman parte del sarcómero en células musculares cardíacas, y las variantes patogénicas de filamentos gruesos son las de mayor frecuencia y peor pronóstico. En este artículo se describen la herencia mendeliana de la enfermedad y la relación con muerte súbita de los genes más frecuentemente encontrados en ella: MYBPC3 y MYH7.

Prenatal diagnosis and genetic analysis of a family with hypertrophic cardiomyopathy / 临床检验杂志

Objective@#To explore the relationship between HCM pathogenic gene mutations and clinical phenotypes by analyzing the prenatal diagnosis and genetic characteristics of a pregnant woman from a family with hypertrophic cardiomyopathy (HCM). @*Methods@#The clinical data of the proband and her family members was collected. The DNA was extracted from the peripheral blood, amniotic fluid cells and cultured amniotic fluid cells of proband. Next generation sequencing (NGS) was utilized for screening pathogenetic loci of the proband. The suspected mutation sequences of HCM pathogenic candidate genes MYH7 and MYBPC3 were directly sequenced after PCR. Pathogenicity prediction of amniotic fluid cells was performed by using genetic data and bioinformatics software, such as Mutation taster, PolyPhen-2 and ANTHEPROT. @*Results@#The sequencing results showed that heterozygous mutations of MYH7 c.1988G＞A (p.Arg663His) and MYBPC3 c.151G＞A (p.Ala51Thr) were found in the proband. The phenotype of her father was normal, and no abnormal mutations were detectable. Her mother also showed normal phenotype but carried MYBPC3 c.151G＞A heterozygous mutation. Only MYH7 c.1988G＞A heterozygous mutation was found in the fetus and no abnormal variation of MYBPC3 was showed. The prediction of mutation effect and analysis of protein structure and function revealed that the two missense mutations could affect the hydrophobicity and antigenicity of the protein. The genetic data demonstrated MYH7 c.1988G＞A was defined as a pathogenic mutation. @*Conclusion@#MYH7 c.1988G＞A should be a newly generated pathogenic mutation in the proband, or caused by reproductive chimerism of her parents. MYBPC3 c.151G＞A mutation may promote the occurrence of HCM. Although the fetus only carries MYH7 c.1988G＞A, her phenotype may still display as HCM.

The early diagnosis of MYH7 gene mutation carriers of hypertrophic cardiomyopathy using multi-parameter analysis model by conventional two-dimensional echocardiography and three-dimensional speckle tracking imaging / 中华超声影像学杂志

Objective To create multi-parameter analysis model by conventional two-dimensional echorcardiography( 2DE) and three-dimensional speckle tracking imaging( 3D-STI) in order to improve the early diagnosis in MYH7G + P- mutation carriers of familiar hypertrophic cardiomyopathy( HCM ) . Methods Twenty-eight MYH7 mutation carriers without left ventricular hypertrophy ( MYH7G + P- ) were enrolled as the research group , while 27 MYBPC3 mutation carriers without left ventricular hypertrophy ( MYBPC3G + P- ) were selected as the control group . The clinical data ,conventional 2DE and tissue Doppler imaging ( TDI) parameters of the two groups were acquired ,including the maximum of the thickness of interventricular septum( IVS) and left ventricular posterior ventricular wall thickness( LVPWT ) in end of diastole ,mitral flow E and A velocities ,E peak deceleration time( EDT ) ,atrioventricular filling time ,mitral annulus velocity of interventricular septum IVS-e' and lateral wall L-e' ,interventricular septum IVS-a' and lateral wall L-a' peak in diastole ,calculate mean value e' and a' ,and calculate E/ e' ,E/A ,left atrial volume index( LAVI) ,left ventricular mass index( LVMI) ,left ventricular ejection fraction( LVEF) and isovolumic relaxation time( IVRT ) ,isovolumic contraction time( IVCT ) . The global longitudinal peak strain( GLS) , global radial peak strain( GRS) ,global circumferential peak strain( GCS) and global area peak strain( GAS) were acquired by 3D-STI . All parameters were compared between research group and control group . Results Compared with the control group ,research group significantly increased in LAVI , maximum IVS and LVPWT ,LVMI and GAS( P < 0 .01) . There were no significant difference in TDI parameters( P > 0 .05) . For single parameter ,the area under ROC curve( AUC) were successively LVPWT > LAVI > IVS > LVMI >GAS( 0 .772 ,0 .738 ,0 .733 ,0 .719 ,0 .714 ,respectively) . AUC of multi-parameters was 0 .912 ,the sensitivity and specificity were 85 .2％ and 96 .3％ ,respectively . Conclusions Multi-parameter analysis model by conventional 2DE and 3D-STI can significantly improve the recognition efficiency of early diagnosis MYH7G + P- of familiar HCM . With further ,maximum LVPWT is an independent predictor of distinction MYH7G + P- and MYBPC3G + P- .

Genetic variations of b-MYH7 in Venezuelan patients with hypertrophic cardiomyopathy / Variaciones genéticas en el gen MYH7 en pacientes venezolanos con miocardiopatía hipertrófica

Hypertrophic cardiomyopathy (HCM) is a cardiac disease, characterized by marked hypertrophy and genetic variability. HCM has been associated with sarcomere protein mutations, being cardiac b-myosin (coded by the MYH7 gene) and myosin binding protein C (coded by the MYBPC3 gene) the most frequently affected proteins. As in Venezuela only the clinical analysis are performed in HCM patients, we decided to search for genetic variations in the MYH7 gene. Coding regions, including the junction exon-intron of the MYH7 gene, were studied in 58 HCM patients, whose samples were collected at the ASCARDIO Hospital (Barquisimeto, Lara state, Venezuela) and 106 control subjects from the ASCARDIO Hospital and the IVIC (Barquisimeto Lara state and Miranda, Venezuela, respectively). The blood samples were analyzed by genomic DNA isolation, followed by polymerase chain reaction and sequence analysis. The screening of the MYH7 gene revealed eight already reported polymorphic variants, as well as two intronic variations in these HCM patients. Neither any missense mutations nor other pathological mutations in the MYH7 gene were found in the HCM patients.

La miocardiopatía hipertrófica (MH) es una enfermedad cardiaca primaria, caracterizada por una marcada hipertrofia y variabilidad genética. MH ha sido asociada con mutaciones en las proteínas del sarcómero, siendo la beta miosina cardiaca, codificada por el gen MYH7 y la proteína de unión a miosina C, codificada por el gen MYBPC3, las principalmente afectadas. En Venezuela únicamente se realiza el diagnóstico clínico de MH, por lo cual el objetivo principal de este trabajo fue realizar el análisis genético en los pacientes, iniciando con el gen MYH7. Para ello, se estudió la región codificante, incluyendo la región de unión exón-intron del gen MYH7 en 58 pacientes provenientes de ASCARDIO (Barquisimeto, estado Lara) y 106 controles provenientes de ASCARDIO e IVIC (estados Lara y Miranda, Venezuela). Se colectaron las muestras de sangre para el aislamiento del ADN genómico, se realizó la técnica de PCR, seguido del análisis de secuencias para la detección de mutaciones en pacientes y controles. Se encontraron 8 polimorfismos previamente reportados, y 2 variaciones intrónicas. No se encontraron mutaciones que involucraran un cambio de aminoácido en ninguno de los exones del gen MYH7 de la beta miosina cardiaca.