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    Implication of Tumor Necrosis Factor alpha in dilated cardiomyopathy due to LMNA mutation
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    Abstract Dilated cardiomyopathy is characterised by dilatation and impaired contraction of the left ventricle or both ventricles, which is the most common childhood cardiomyopathy. In recent years, it has been recognised that many sorts of genetic mutations may contribute to dilated cardiomyopathy. We now report a rare association of dilated cardiomyopathy with site mutation of BMPR2 gene. We did not find such an association reported in the medical literature.
    Dilated Cardiomyopathy
    Citations (0)
    The lamin A/C (LMNA) gene encodes lamins A and C, which have an important role in nuclear cohesion and chromatin organization. Mutations in this gene usually lead to the so-called laminopathies, the primary cardiac manifestations of which are dilated cardiomyopathy and intracardiac conduction defects. Some mutations, associated with lipodystrophy but not cardiomyopathy, have been linked to metabolic abnormalities such as diabetes and severe dyslipidemia. Herein we describe a new phenotype associated with a mutation in exon 11 of the LMNA gene: hypertrophic cardiomyopathy, atrioventricular block, severe dyslipidemia and diabetes. A 64-year-old woman with hypertrophic cardiomyopathy and a point mutation in exon 11 of the LMNA gene (c.1718C>T, Ser573Leu) presented with severe symptomatic ventricular hypertrophy and left ventricular outflow tract obstruction. She underwent septal alcohol ablation, followed by Morrow myectomy. The patient was also diagnosed with severe dyslipidemia, diabetes and obesity, and fulfilled diagnostic criteria for metabolic syndrome. No other characteristics of LMNA mutation-related phenotypes were identified. The development of type III atrioventricular block with no apparent cause, and mildly depressed systolic function, prompted referral for cardiac resynchronization therapy. In conclusion, the association between LMNA mutations and different phenotypes is complex and not fully understood, and can present with a broad spectrum of severity. O gene LMNA codifica a lâmina A/C, com importante papel na manutenção da coesão nuclear e organização da cromatina. Mutações neste gene estão geralmente associadas a doenças denominadas laminopatias. As manifestações cardíacas primárias destas mutações são miocardiopatia dilatada e defeitos da condução intracardíaca. Algumas mutações, associadas a lipodistrofia, mas não cardiomiopatia, estão também associadas a alterações metabólicas, como diabetes ou dislipidemia grave. Assim, descrevemos um novo fenótipo associado a uma mutação no exão 11 do gene LMNA: miocardiopatia hipertrófica, bloqueio auriculoventricular, dislipidemia grave e diabetes. Apresentamos a situação clínica de uma doente de 64 anos de idade, com miocardiopatia hipertrófica e mutação patogénica identificada no exão 11 do gene LMNA (c.1718C>T, Ser573Leu). A doente apresentou-se com hipertrofia ventricular grave sintomática, obstrutiva, refratária à terapêutica médica. Foi submetida a ablação septal por álcool e, posteriormente, a miectomia cirúrgica. Foi também diagnosticada dislipidemia grave, diabetes e obesidade, cumprindo os critérios para síndrome metabólica. Não foi identificada nenhuma outra característica fenotípica associada a mutações no gene LMNA. A doente foi ainda submetida a terapêutica de ressincronização cardíaca após o desenvolvimento de bloqueio auriculoventricular completo, sem causa aparente, na presença de ligeiro compromisso da função sistólica ventricular. A correlação de mutações no gene LMNA com diferentes fenótipos é complexa e ainda não completamente compreendida, englobando um largo espectro de gravidade clínica.
    LMNA
    Dilated Cardiomyopathy
    Citations (10)
    Abstract Most individuals with cardiomyopathy associated with variants of the LMNA (lamin A) gene present with cardiac conduction abnormalities followed by dilated cardiomyopathy and cardiac failure; some also have skeletal muscle weakness. In this report, an individual with restrictive cardiomyopathy presenting with conduction defects followed by cardiac dysfunction of a restrictive nature eventually requiring cardiac transplantation is described. Subsequently, progressive skeletal muscle weakness became evident. The finding of a new LMNA pathologic gene variant in this patient increases the options for genetic testing of individuals with restrictive cardiomyopathy.
    LMNA
    Restrictive cardiomyopathy
    Dilated Cardiomyopathy
    Muscle weakness
    Citations (11)
    LMNA mutations are amongst the most important causes of familial dilated cardiomyopathy. The most important cause of arrhythmogenic right ventricular cardiomyopathy (ARVC) is desmosomal pathology. The aim of the study was to elucidate the role of LMNA mutations among Finnish cardiomyopathy patients. We screened 135 unrelated cardiomyopathy patients for LMNA mutations. Because of unusual phenotype, two patients were screened for the known Finnish ARVC-related mutations of desmosomal genes, and their Plakophilin-2b gene was sequenced. Myocardial samples from two patients were examined by immunohistochemical plakoglobin staining and in one case by electron microscopy. We found a new LMNA mutation Phe237Ser in a family of five affected members with a cardiomyopathy affecting primarily the right side of the heart. The phenotype resembles ARVC but does not fulfill the Task Force Criteria. The main clinical manifestations of the mutation were severe tricuspid insufficiency, right ventricular enlargement and failure. Three of the affected patients died of the heart disease, and the two living patients received heart transplants at ages 44 and 47. Electron microscopy showed nuclear blebbing compatible with laminopathy. Immunohisto - chemical analysis did not suggest desmosomal pathology. No desmosomal mutations were found. The Phe237Ser LMNA mutation causes a phenotype different from traditional cardiolaminopathy. Our findings suggest that cardiomyopathy affecting primarily the right side of the heart is not always caused by desmosomal pathology. Our observations highlight the challenges in classifying cardiomyopathies, as there often is significant overlap between the traditional categories.
    LMNA
    Plakoglobin
    Dilated Cardiomyopathy
    Dilated cardiomyopathy (DCM) refers to a spectrum of heterogeneous myocardial disorders characterized by ventricular dilation and depressed myocardial performance in the absence of hypertension, valvular, congenital, or ischemic heart disease. Mutations in LMNA gene, encoding for lamin A/C, account for 10% of familial DCM. LMNA-related cardiomyopathies are characterized by heterogeneous clinical manifestations that vary from a predominantly structural heart disease, mainly mild-to-moderate left ventricular (LV) dilatation associated or not with conduction system abnormalities, to highly pro-arrhythmic profiles where sudden cardiac death (SCD) occurs as the first manifestation of disease in an apparently normal heart. In the present study, we select, among 77 DCM families referred to our center for genetic counselling and molecular screening, 15 patient heterozygotes for LMNA variants. Segregation analysis in the relatives evidences other eight heterozygous patients. A genotype-phenotype correlation has been performed for symptomatic subjects. Lastly, we perform in vitro functional characterization of two novel LMNA variants using dermal fibroblasts obtained from three heterozygous patients, evidencing significant differences in terms of lamin expression and nuclear morphology. Due to the high risk of SCD that characterizes patients with lamin A/C cardiomyopathy, genetic testing for LMNA gene variants is highly recommended when there is suspicion of laminopathy.
    LMNA
    Dilated Cardiomyopathy
    Citations (13)