Cuando la genética estaba oculta: miocardiopatía hipertrófica por variante MYBPC3 c. 1102A>T (p.Lys368*) refractaria a manejo médico: reporte de un caso / When genetics were hidden: hypertrophic cardiomyopathy due to MYBPC3 c. 1102A>T (p.Lys368*) variant refractory to medical management: case report / Quando a genética estava oculta: cardiomiopatia hipertrófica por variante MYBPC3 c. 1102A>T (p.Lys368*) refractária à manejo médico: reporte de um caso

La miocardiopatía hipertrófica es cada vez más diagnosticada. Es una condición genética que genera hipertrofia miocárdica, fibrosis, isquemia y apoptosis con obstrucción del tracto de salida del ventrículo izquierdo. Puede generar síncope, falla cardíaca y muerte súbita. El tratamiento es farmacológico y se requiere cirugía si hay refractariedad. Se presenta un caso de miocardiopatía hipertrófica asociada a variante genética patogénica en un paciente no respondedor a manejo médico óptimo. La importancia de este artículo radica en lo determinante que es la genética para el abordaje diagnóstico y el establecimiento del origen y pronóstico de esta enfermedad.

Hypertrophic cardiomyopathy is increasingly diagnosed. It is a genetic condition that leads to myocardial hypertrophy, fibrosis, ischemia, and apoptosis with obstruction of the left ventricular outflow tract. It can result in syncope, heart failure, and sudden death. Treatment is pharmacological, and surgery is required in cases of refractoriness. A case of hypertrophic cardiomyopathy associated with a pathogenic genetic variant is presented in a patient unresponsive to optimal medical management. The importance of this article lies in how crucial genetics is for the proper diagnostic approach and the establishment of the origin and prognosis of this disease.

A miocardiopatia hipertrófica está sendo diagnosticada cada vez mais. É uma condição genética que leva à hipertrofia miocárdica, fibrose, isquemia e apoptose com obstrução do trato de saída do ventrículo esquerdo. Pode resultar em síncope, insuficiência cardíaca e morte súbita. O tratamento é farmacológico e a cirurgia é necessária em casos de refratariedade. Apresenta-se um caso de miocardiopatia hipertrófica associada a uma variante genética patogênica em um paciente não responsivo ao manejo médico ótimo. A importância deste artigo reside na determinante genética para a abordagem diagnóstica adequada e para o estabelecimento da origem e prognóstico desta doença.

Ecoestresse físico na cardiomiopatia hipertrófica: como, quando e por quê? / Exercise stress echocardiography in hypertrophic cardiomyopathy: how, when and why?

Resumo Historicamente, o papel do ecocardiograma de estresse físico no manejo da cardiomiopatia hipertrófica tem sido negligenciado na prática clínica, de acordo com a análise das diretrizes do American College of Cardiology/ American Heart Association de 2002, que recomendavam cautela no uso dessa metodologia, em portadores de cardiomiopatia hipertrófica, devido ao risco de possível ocorrência tanto de arritmia cardíaca, como de colapso hemodinâmico no esforço. Atualmente, o estresse físico na cardiomiopatia hipertrófica integra a avaliação rotineira de pacientes sintomáticos com ou sem gradiente da via de saída do ventrículo esquerdo < 50 mmHg, em repouso. Para este grupo, é um método seguro e confiável para medir o gradiente da via de saída do ventrículo esquerdo durante o esforço e sólido diferenciador de pacientes com cardiomiopatia hipertrófica não obstrutivos (gradiente ausente, tanto em repouso quanto no esforço) daqueles com gradientes lábeis (gradiente ausente no repouso e presente no esforço). Portanto, na avaliação da cardiomiopatia hipertrófica, o estresse físico é igualmente útil na quantificação do grau de regurgitação mitral, nas alterações da contratilidade segmentar do ventrículo esquerdo e na avaliação da função diastólica do ventrículo esquerdo, diante do esforço, sendo capaz de predizer o futuro desenvolvimento de sintomas de insuficiência cardíaca. O método é também importante na determinação das diferentes estratégias de tratamento para cada paciente, desde a miomectomia cirúrgica ou a ablação septal alcoólica, para aqueles com gradiente lábil, com sintomas limitantes e refratários ao tratamento medicamentoso versus transplante cardíaco para aqueles sem gradiente.(AU)

Hypertrophic cardiomyopathy masked by pericarditis

Hypertrophic cardiomyopathy used to be regarded as a rare untreatable cause of sudden death in young male athletes. This report is the case of a middle-aged female patient with hereditary hypertrophic cardiomyopathy masked by superimposed pericarditis and revealed by autopsy. This case report illustrates how co-morbidity can hide a crucial diagnosis. This case report also illustrates the value of autopsy disclosing a familial disease that is increasingly recognized and dramatically more treatable than a few decades ago. Sudden death due to hypertrophic cardiomyopathy has become preventable, if the diagnosis is made soon enough. The lessons for patient care from this case include the importance of not missing the diagnosis of hypertrophic cardiomyopathy in female patients.

Caracterización clínica y molecular de niños con síndrome de Noonan y otras RASopatías en Argentina / Clinical and molecular characterization of children with Noonan syndrome and other RASopathies in Argentina

Introducción. Las RASopatías son un conjunto de síndromes fenotípicamente superpuestos causados por mutaciones en genes implicados en la vía RAS/MAPK. La herencia es autosómica dominante, presentan características clínicas comunes, como baja talla, dismorfias craneofaciales, cardiopatia congénita, manifestaciones ectodérmicas y mayor riesgo de cáncer. El diagnóstico molecular es clave. Objetivo. Identificar mutaciones en los genes PTPN11, SOS1,RAF1, BRAFy HRAS,y comparar las principales características clínicas en pacientes con confirmación molecular. Población y métodos. Se estudiaron niños con diagnóstico clínico de RASopatía evaluados entre agosto de 2013 y febrero de 2017. Resultados. Se identificaron mutaciones en el 71 % (87/122) de los pacientes. El estudio molecular confirmó el diagnóstico en el 73 % de los pacientes con síndrome de Noonan. La mutación más prevalente fue c.922A>G (p.Asn308Asp) en el gen PTPN11. Se detectó una variante no descrita en RAF1, c.1467G>C (p.Leu489Phe). Se confirmó el sindrome cardiofaciocutáneo en el 67 % de los casos con mutaciones en el gen BRAF. El síndrome de Costello y el síndrome de Noonan con múltiples lentigos se confirmaron en todos los casos. Conclusión. La confirmación del diagnóstico clínico permitió un diagnóstico diferencial más preciso. Se determinó la prevalencia de las mutaciones en PTPN11 (el 58 %), SOS1 (el 10 %) y RAF1 (el 5 %) en niños con síndrome de Noonan, en PTPN11 (el 100 %) en el sindrome de Noonan con múltiples lentigos, en BRAF (el 67 %) en el síndrome cardiofaciocutáneo y en HRAS (el 100 %) en el sindrome de Costello.

Introduction. RASopathies are a set of syndromes with phenotypic overlapping features caused by gene mutations involved in the RAS/MAPK pathway. They are autosomal dominantly inherited and share common clinical characteristics, including short stature, craniofacial dysmorphisms, congenital heart disease, ectodermal manifestations, and a higher risk for cancer. A molecular diagnosis is a key factor. Objective. To identify PTPN11, SOS1, RAF1, BRAF, and HRAS mutations and compare the main clinical characteristics of patients with molecular confirmation. Population and methods. Children with a clinical diagnosis of RASopathy assessed between August 2013 and February 2017. Results. Mutations were identified in 71 % (87/122) of patients. The molecular test confirmed diagnosis in 73 % of patients with Noonan syndrome. The most prevalent mutation was c.922A>G (p.Asn308Asp) in the PTPN11 gene. A previously undescribed variant in RAF1 was detected: c.1467G>C (p.Leu489Phe). Cardiofaciocutaneous syndrome was confirmed in 67 % of cases with BRAF mutations. Costello syndrome and Noonan syndrome with multiple lentigines were confirmed in all cases. Conclusion. The confirmation of clinical diagnosis allowed for a more accurate differential diagnosis. The prevalence of PTPN11 (58 %), SOS1 (10 % ), and RAF1 mutations (5 %) in children with Noonan syndrome, of PTPN11 mutations (100 %) in those with Noonan syndrome with multiple lentigines, of BRAF mutations (67 %) in those with cardiofaciocutaneous syndrome, and of HRAS mutations (100 %) in those with Costello syndrome was determined.

Qual o valor da cintilografia de perfusão e PET cardíaco na miocardiopatia hipertrófica / What is the value of perfusion scintigraphy and cardiac PET in hypertrophic cardiomyopathy

A miocardiopatia hipertrófica é a cardiopatia hereditária mais comum e acomete cerca de 1:500 indivíduos na população geral. O diagnóstico, que nem sempre é simples pela variação fenotípica e pela concomitância de outras patologias, baseia-se, inicialmente, em critérios eletrocardiográficos e ecocardiográficos, e na ausência de outras doenças que cursem com hipertrofia ventricular. Tendo como base celular o desarranjo miofibrilar e a fibrose com alterações hemodinâmicas decorrentes, a miocardiopatia hipertrófica pode revelar isquemia miocárdica (não relacionada à aterosclerose) e morte súbita. Assim, a avaliação da repercussão funcional por meio da cintilografia de perfusão miocárdica pela técnica Single Photon Emission Computed Tomography (SPECT) tem ganhado espaço, uma vez que 25% dos pacientes com miocardiopatia hipertrófica demonstram defeitos de perfusão fixos ou isquêmicos. Neste âmbito, notam-se alterações perfusionais que não estão necessariamente associadas ao tipo de miocardiopatia hipertrófica, mas conseguem predizer morbimortalidade nestes indivíduos. Outra técnica cintilográfica mais recente é a tomografia por emissão de pósitrons (PET), que se destaca na avaliação da microcirculação, na reserva de fluxo coronário e no metabolismo miocárdico. Em pacientes com miocardiopatia hipertrófica, estudos têm demonstrado resultados desfavoráveis quanto menores o fluxo sanguíneo miocárdico e a reserva de fluxo coronário. A avaliação miocárdica metabólica pela PET parece útil no entendimento fisiopatológico desta doença e na avaliação prognóstica da ablação alcoólica, procedimento realizado em formas obstrutivas graves. Assim, esta revisão aborda o papel da cardiologia nuclear pelas técnicas SPECT e PET miocárdico na avaliação diagnóstica, prognóstica e terapêutica da miocardiopatia hipertrófica

Rastreo de familiares de una paciente con miocardiopatía hipertrófica obstructiva / Family Tracing of a Patient with Hypertrophic Obstructive Miocardiomyopathy

Resumen Introducción: La miocardiopatía hipertrófica familiar es la modalidad hereditaria autosómica dominante de la miocardiopatía hipertrófica, de penetrancia incompleta y expresión variable. Se exponen los estudios realizados a los familiares de un caso índice de miocardiopatía hipertrófica obstructiva, dado un 50% de probabilidad de padecer la enfermedad. Material y métodos: A partir de un caso índice se reclutaron familiares (hijos y hermanos) del caso índice, quienes fueron invitados a realizarse electrocardiograma, ecocardiograma transtorácico, prueba de esfuerzo y Holter cardíaco de manera voluntaria. Se aplicó una encuesta semiestructurada para obtener datos sociodemográficos, antecedentes personales, familiares y hábito de práctica de actividad física. Para el diagnóstico se siguieron los criterios utilizados por la guía de la Sociedad española de cardiología. Resultados: En los 11 casos evaluados se identificaron 4 miembros de la familia con criterios diagnósticos de miocardiopatía hipertrófica y 5 con hipertensión arterial. Conclusión: Con el estudio de los familiares de la paciente índice se logró descubrir la afectación de esta enfermedad en 2 familiares de primer grado y en 2 familiares de segundo grado, con predominancia para el sexo masculino (3:1); en la paciente femenina se encontró, además, hipertensión arterial y miocardiopatía hipertrófica asociadas a fibrilación auricular. Ninguno de ellos tuvo historia personal de síncope o resucitación de muerte súbita.

Abstract Introduction: Familial hypertrophic myocardiopathy is a hereditary autosomal dominant trait of hypertrophic myocardiopathy, of incomplete penetrance and variable expression. Studies carried out on the family of an index case of hypertrophic obstructive myocardiopathy gave a 50% probability of suffering from the disease. Material and methods: Family members (children, brothers and sisters) of an index case were recruited and were invited to volunteer to have a transthoracic electrocardiogram, stress test, and Holter test performed. A semi-structured questionnaire was completed in order to obtain sociodemographic data, personal and family history, and physical activity habits. The criteria used in the Spanish Cardiology Society guidelines were followed to make the diagnosis. Results: In the 11 cases evaluated, 4 members of the family were identified with diagnostic criteria of hypertrophic myocardiopathy, and 5 with arterial hypertension. Conclusions: With the study of the family members of the index patient, it was discovered that this disease affected 2 first degree and 2 second degree family members, with a predominance of male gender (3:1). The female case was also found to have arterial hypertension and hypertrophic cardiomyopathy associated with atrial fibrillation. None of them had a personal history of syncope or sudden death resuscitation.

Autopsia molecular en muerte súbita cardíaca neonatal mediante secuenciación de siguiente generación (NGS): presentación de un caso / Molecular autopsy in neonatal sudden cardiac death by next generation sequencing (NGS): presentation of a case

Presentamos un caso de muerte súbita de una lactante de tres meses de edad. La autopsia reveló una miocardiopatía hipertrófica y la muestra de sangre del cordón umbilical almacenada fue utilizada para análisis molecular. Mediante la secuenciación de siguiente generación (NGS) de 4813 genes (exoma clínico), se identificó una variante patogénica en el gen ELAC2, (c.210_222 del p.Gly71ThrfsTer26) en estado heterocigoto y otra variante probablemente patogénica en el mismo gen (c.1177C>T p.His393Tyr) en estado heterocigoto, asociadas con miocardiopatía hipertrófica. Adicionalmente, se identificó una variante patogénica en el exón 358 del gen TTN, (c.104515C>T, het p.Arg34839X) y una VUS (variante de significado incierto) en el gen MYPN (c.2428C>T, p.Arg810Cys), la cual podría tener un efecto aditivo en el fenotipo de la paciente. Así mismo se observa un polimorfismo de riesgo en el exón 16 en el gen LRP8, asociado con enfermedad coronaria (CAD) e infarto de miocardio prematuros (MI) (NM_017522: c.2066G>A, het, p.R689Q). La cardiopatía hereditaria es una causa probable de muerte súbita cardiaca, el análisis molecular por NGS puede ayudar a realizar un diagnóstico precoz para predecir a edad temprana pacientes con riesgo potencial de muerte súbita cardiaca así como un asesoramiento genético dirigido.

We present the case of sudden death in a three month old female infant. The girl died of sudden death, and the autopsy revealed a hypertrophic cardiomyopathy as the underlying alteration. The stored umbilical cord blood sample was used for molecular analysis. A pathogenic heterocigous variant in ELAC2 (c.210_222del, p.Gly71ThrfsTer26), and another probably pathogenic variant in the same gene ( c.1177C> T p.His393Tyr,het) associated with hypertrophic cardiomyopathy was identified. In addition, a pathogenic variant is identified in exon 358 of the TTN gene (c.104515C> T, het p.Arg34839X,het) and a VUS (variant of uncertain significance) in the MYPN gene (c.2428C> T, p.Arg810Cys,het), which may have an additive effect on the patient's phenotype. A risk polymorphism at exon 16 in the LRP8 gene, associated with premature coronary artery disease (CAD) and premature myocardial infarction (MI) (NM_017522: c.2066G> A, het, p.R689Q) was also found. Hereditary heart disease is a probable cause of sudden cardiac death, molecular analysis by NGS can help an early diagnosis and to predict at an early age, the risk of sudden cardiac death as well as directed genetic counseling.

Morte Súbita na Cardiomiopatia Hipertrófica / Sudden Death in Hypertrophic Cardiomyopathy

A cardiomiopatia hipertrófica é uma doença genética do músculo cardíaco, autossômica dominante, caracterizada por hipertrofia ventricular na ausência de qualquer outra condição clínica que leve à sobrecarga do coração. Estima-se prevalência de 1:500, sendo importante causa de morte súbita, especialmente em jovens, com incidência anual em torno de 1%. Entre os marcadores de risco para a ocorrência de arritmias ventriculares malignas e morte súbita neste cenário, enfatizam-se, além de um evento fatal já ocorrido e abortado, história familiar de morte súbita; espessura de parede maior ou igual a 30mm; síncope inexplicada; presença de taquicardia ventricular não sustentada ao Holter; resposta pressórica anormal no teste ergométrico; e presença de realce tardio na ressonância magnética do coração. A presença ou ausência destes marcadores pode definir a necessidade ou não do implante de cardiodesfibrilador implantável como forma de prevenir a morte súbita nestes pacientes. Entretanto, ainda existe muita controvérsia sobre a forma pela qual estes pacientes devam ser estratificados. Sabe-se que estes marcadores não têm o mesmo peso em predizer quem tem mais chance de sofrer um evento fatal. Este fato torna-se particularmente importante quando se constata que o procedimento de implante de cardiodesfibrilador implantável não é isento de complicações, além do impacto econômico, em termos do custo para o sistema de saúde. A proposta deste artigo é a realização de uma revisão sobre os principais aspectos envolvidos na morte súbita destes pacientes, desde a fisiopatologia, a avaliação de risco, a prevenção e as perspectivas futuras.

Prevalence and Phenotypic Expression of Mutations in the MYH7, MYBPC3 and TNNT2 Genes in Families with Hypertrophic Cardiomyopathy in the South of Brazil: A Cross-Sectional Study / Prevalência e Expressão Fenotípica das Mutações nos Genes MYH7, MYBPC3 e TNNT2 em Famílias com Cardiomiopatia Hipertrófica no Sul do Brasil: Um Estudo Transversal

Abstract Background: Mutations in sarcomeric genes are found in 60-70% of individuals with familial forms of hypertrophic cardiomyopathy (HCM). However, this estimate refers to northern hemisphere populations. The molecular-genetic profile of HCM has been subject of few investigations in Brazil, particularly in the south of the country. Objective: To investigate mutations in the sarcomeric genes MYH7, MYBPC3 and TNNT2 in a cohort of HCM patients living in the extreme south of Brazil, and to evaluate genotype-phenotype associations. Methods: Direct DNA sequencing of all encoding regions of three sarcomeric genes was conducted in 43 consecutive individuals of ten unrelated families. Results: Mutations for CMH have been found in 25 (58%) patients of seven (70%) of the ten study families. Fourteen (56%) individuals were phenotype-positive. All mutations were missense, four (66%) in MYH7 and two (33%) in MYBPC3. We have not found mutations in the TNNT2 gene. Mutations in MYH7 were identified in 20 (47%) patients of six (60%) families. Two of them had not been previously described. Mutations in MYBPC3 were found in seven (16%) members of two (20%) families. Two (5%) patients showed double heterozygosis for both genes. The mutations affected different domains of encoded proteins and led to variable phenotypic expression. A family history of HCM was identified in all genotype-positive individuals. Conclusions: In this first genetic-molecular analysis carried out in the south of Brazil, we found mutations in the sarcomeric genes MYH7 and MYBPC3 in 58% of individuals. MYH7-related disease was identified in the majority of cases with mutation.

Resumo Fundamento: Mutações em genes do sarcômero são encontradas em 60-70% dos indivíduos com formas familiares de cardiomiopatia hipertrófica. (CMH). Entretanto, essa estimativa refere-se a populações de países do hemisfério norte. O perfil genético-molecular da CMH foi tema de poucos estudos no Brasil, particularmente na região sul do país. Objetivo: Realizar a pesquisa de mutações dos genes sarcoméricos MYH7, MYBPC3 e TNNT2 numa coorte de CMH estabelecida no extremo sul do Brasil, assim como avaliar as associações genótipo-fenótipo. Métodos: Sequenciamento direto do DNA de todas as regiões codificantes dos três genes sarcoméricos foi realizada em 43 indivíduos consecutivos de dez famílias não-relacionadas. Resultados: Mutações para CMH foram encontradas em 25 (58%) indivíduos de sete (70%) das dez famílias estudadas, sendo 14 (56%) deles fenótipo-positivos. Todas as mutações eram missense, quatro (66%) no gene MYH7 e duas (33%) no gene MYBPC3. Não foram encontradas mutações no gene TNNT2. Mutações em MYH7 foram identificadas em 20 (47%) indivíduos de seis (60%) famílias. Duas delas não haviam sido previamente relatadas. Mutações de MYBPC3 foram detectadas em sete (16%) membros de duas (20%) famílias. Dois (5%) indivíduos apresentaram dupla heterozigose com mutações em ambos os genes. As mutações acometeram distintos domínios das proteínas codificadas e produziram expressão fenotípica variável. História familiar de CMH foi identificada em todos os indivíduos genótipo-positivos. Conclusões: Nessa primeira análise genético-molecular da CMH realizada no sul do Brasil, foram encontradas mutações nos genes sarcoméricos MYH7 e MYBPC3 em 58% dos indivíduos. Doença relacionada ao gene MYH7 foi identificada na maioria dos casos com mutação.

Extreme septal hypertrophy in an adolescent with congenital familial hypertrophic cardiomyopathy

No abstract available.

Asymmetric left ventricular hypertrophy associated with morbid obesity mimicking familial hypertrophic cardiomyopathy

Asymmetric septal hypertrophy with systolic anterior motion of the mitral valve is frequently a phenotypic, but not pathognomonic, expression of genetic hypertrophic cardiomyopathy (HCM) with or without obstruction. It can, however, be associated nonspecifically with other forms of increased left ventricular (LV) afterload. We herein report the case of a young man with obesity cardiomyopathy and heart failure who presented with asymmetric septal hypertrophy and marked LV hypertrophy, and endomyocardial biopsy ruled out genetic HCM.

Age-related changes in familial hypertrophic cardiomyopathy phenotype in transgenic mice and humans / 华中科技大学学报（医学）（英德文版）

β-myosin heavy chain mutations are the most frequently identified basis for hypertrophic cardiomyopathy (HCM). A transgenic mouse model (αMHC(403)) has been extensively used to study various mechanistic aspects of HCM. There is general skepticism whether mouse and human disease features are similar. Herein we compare morphologic and functional characteristics, and disease evolution, in a transgenic mouse and a single family with a MHC mutation. Ten male αMHC(403) transgenic mice (at t-5 weeks, -12 weeks, and -24 weeks) and 10 HCM patients from the same family with a β-myosin heavy chain mutation were enrolled. Morphometric, conventional echocardiographic, tissue Doppler and strain analytic characteristics of transgenic mice and HCM patients were assessed. Ten male transgenic mice (αMHC(403)) were examined at ages -5 weeks, -12 weeks, and -24 weeks. In the transgenic mice, aging was associated with a significant increase in septal (0.59±0.06 vs. 0.64±0.05 vs. 0.69±0.11 mm, P<0.01) and anterior wall thickness (0.58±0.1 vs. 0.62±0.07 vs. 0.80±0.16 mm, P<0.001), which was coincident with a significant decrease in circumferential strain (-22%±4% vs. -20%±3% vs. -19%±3%, P=0.03), global longitudinal strain (-19%±3% vs. -17%±2% vs. -16%±3%, P=0.001) and E/A ratio (1.9±0.3 vs. 1.7±0.3 vs. 1.4±0.3, P=0.01). The HCM patients were classified into 1st generation (n=6; mean age 53±6 years), and 2nd generation (n=4; mean age 32±8 years). Septal thickness (2.2±0.9 vs. 1.4±0.1 cm, P<0.05), left atrial (LA) volume (62±16 vs. 41±5 mL, P=0.03), E/A ratio (0.77±0.21 vs. 1.1±0.1, P=0.01), E/e' ratio (25±10 vs. 12±2, P=0.03), global left ventricular (LV) strain (-14%±3% vs. -20%±3%, P=0.01) and global LV early diastolic strain rate (0.76±0.17 s(-1) vs. 1.3±0.2 s-1, P=0.01) were significantly worse in the older generation. In β-myosin heavy chain mutations, transgenic mice and humans have similar progression in morphologic and functional abnormalities. The αMHC(403) transgenic mouse model closely recapitulates human disease.

Echocardiographic study of double mutations of myosin-binding protein C3 gene in Chinese patients with familial hypertrophic cardiomyopathy / 中南大学学报(医学版)

OBJECTIVE@#To determine the associated mutations in myosin-binding protein C3 (MYBPC3) in Chinese patients with family hypertrophic cardiomyopathy (FHCM) and to analyze the genotype and phenotype correlation.@*METHODS@#One family with 27 family members affected with FHCM was chosen for the study. The full encoding exons of MYBPC3 were amplified with PCR and the products were sequenced. The clinical data and echocardiography were collected.@*RESULTS@#Two missense mutations in the family were identified: one was C.2526C>G mutation which caused a tyrosine (Tyr) to terminator exchange at amino acid residue 842 and the other was C.2971G>A mutation which resulted in a valine (Val) to methionine (Met) exchange at amino acid residue 991. Four patients in the family suffered from HCM with asymmetric interventricular septal hypertrophy. The left ventricular diastolic function was significantly reduced. Signs of regional diastolic abnormalities occurred in some mutation carriers.@*CONCLUSION@#Severe hypertrophy and diastolic dysfunction of the disease are compatible with the presence of double mutations in MYBPC3. Signs of regional diastolic abnormalities suggest a primary response to the mutations of MYBPC3 expression.

Genetic heterogeneity for autosomal dominant familial hypertrophic cardiomyopathy in a Pakistani family

To identify the gene causing inherited hypertrophic cardiomyopathy [HCM] in a Pakistani family. Cross-sectional, observational study. Department of Cardiology, Shifa International Hospital and Biomedical and Genetic Engineering Laboratories, Islamabad, from 2005 to 2007. A large family of 17 individuals was included in this study. In the family 6 members were suffering from hypertrophic cardiomyopathy. Linkage analysis was carried out to map the disease-causing gene. Genomic DNA from each individual of the whole family was genotyped for microsatellite markers for all the known HCM loci followed by a whole genome search. Automated DNA sequencing was done for mutation identification in the candidate genes. Linkage analysis of 17 family members showed a maximum two point Lod score of 3.97 with marker D1S1660 at chromosome 1q 32.2. A disease region of 4.16cM was defined by proximal and distal cross-overs with markers GATA135F02 and D1S3715 respectively. This region contained the candidate genes TNNT2 [cardiac troponin T] and TNNI1 [troponin I 1]. Direct sequencing of these genes for the whole family containing 17 members showed no diseaseassociated mutation in either of these genes. Through linkage analysis, a disease locus for HCM family was mapped within a region of 4.16cM at chromosome 1q31.3-q32.1. So far no disease-associated mutation has been found in the candidate genes