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1.
Genetics of Dilated Cardiomyopathy.
Fu, Y, Eisen, HJ
Current cardiology reports. 2018;(11):121
Abstract
PURPOSE OF REVIEW Dilated cardiomyopathy (DCM) is characterized by left ventricular dilation and systolic function and is the most common among all cardiomyopathies. Familial DCM makes up a significant portion of cases, and approximately 40 genes are identified as involved in the pathogenesis of heart failure, each affecting a specific part of cellular mechanisms. The purpose of this review is to summarize recent findings and the current understanding of the most common gene mutations identified associated with DCM. RECENT FINDINGS Next-generation sequencing is a comprehensive gene analysis technique used to discover more mutation variants and also to learn about the impact of mutations in relationship to clinical presentations. A variety of techniques are utilized to study different gene mutations, such as genotype-phenotype association analysis or whole-exome sequencing, to understand the natural history of diseases. For certain genetic abnormalities, information is helpful in developing potential therapeutic treatment targeting mutations. More treatment options are hopeful with the understanding of specific genetic mutations and their pathogenic mechanism. It also suggests the importance of genetic assessment and counseling for family members of an affected patient, in order to provide potential early diagnosis and better clinical management of DCM.
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QTc prolongation and torsades de pointes due to a coadministration of fluoxetine and amiodarone in a patient with implantable cardioverter-defibrillator: Case report and review of the literature.
Wei, A, Peng, J, Gu, Z, Li, J
Medicine. 2017;(49):e9071
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RATIONALE Drug-induced prolongation of the corrected QT interval (QTc) may lead to serious and potentially life-threatening ventricular tachyarrhythmia, such as torsades de pointes (Tdp), which is worthy of clinical attention. Here, we report 1 case of Tdp after a coadministration of fluoxetine and amiodarone. PATIENT CONCERNS A 62-year-old Chinese male who placed with the implanted cardioverter-defibrillator (ICD) appeared the QTc prolongation and Tdp after the concurrent administration of fluoxetine and amiodarone. DIAGNOSES Torsades de pointes (Tdp). INTERVENTIONS The patient was treated with magnesium and potassium immediately. Her ICD-brady pacing mode was reprogrammed to 90 bpm. Meanwhile, both of fluoxetine and amiodarone were discontinued. OUTCOMES The further episodes of Tdp were prevented. After a few days, the QTc gradually decreased without clinically significant arrhythmias. LESSONS The present case demonstrates that a potential drug-drug interaction (DDI) may lead to a life-threatening drug adverse reaction (ADR) especially in special subjects. Therefore, clinicians should closely monitor the electrocardiogram (ECG) when QTc-prolonging agents are given to patients with cardiac abnormalities, and avoid combining 2 QTc-prolonging drugs.
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Dilated Cardiomyopathy Revealing Cushing Disease: A Case Report and Literature Review.
Marchand, L, Segrestin, B, Lapoirie, M, Favrel, V, Dementhon, J, Jouanneau, E, Raverot, G
Medicine. 2015;(46):e2011
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Cardiovascular impairments are frequent in Cushing's syndrome and the hypercortisolism can result in cardiac structural and functional changes that lead in rare cases to dilated cardiomyopathy (DCM). Such cardiac impairment may be reversible in response to a eucortisolaemic state.A 43-year-old man with a medical past of hypertension and history of smoking presented to the emergency department with global heart failure. Coronary angiography showed a significant stenosis of a marginal branch and cardiac MRI revealed a nonischemic DCM. The left ventricular ejection fraction (LVEF) was estimated as 28% to 30%. Clinicobiological features and pituitary imaging pointed toward Cushing's disease and administration of adrenolytic drugs (metyrapone and ketoconazole) was initiated. Despite the normalization of cortisol which had been achieved 2 months later, the patient presented an acute heart failure. A massive mitral regurgitation secondary to posterior papillary muscle rupture was diagnosed as a complication of the occlusion of the marginal branch. After 6 months of optimal pharmacological treatment for systolic heart failure, as well as treatment with inhibitors of steroidogenesis, there was no improvement of LVEF. The percutaneous mitral valve was therefore repaired and a defibrillator implanted. The severity of heart failure contraindicated pituitary surgery and the patient was instead treated by stereotaxic radiotherapy.This is the first case reporting a Cushing's syndrome DCM without improvement of LVEF despite normalization of serum cortisol levels.
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Deception in simplicity: hereditary phospholamban mutations in dilated cardiomyopathy.
Young, HS, Ceholski, DK, Trieber, CA
Biochemistry and cell biology = Biochimie et biologie cellulaire. 2015;(1):1-7
Abstract
The sarcoplasmic reticulum (SR) calcium pump (SERCA) and its regulator phospholamban are required for cardiovascular function. Phospholamban alters the apparent calcium affinity of SERCA in a process that is modulated by phosphorylation via the β-adrenergic pathway. This regulatory axis allows for the dynamic control of SR calcium stores and cardiac contractility. Herein we focus on hereditary mutants of phospholamban that are associated with heart failure, such as Arg(9)-Cys, Arg(9)-Leu, Arg(9)-His, and Arg(14)-deletion. Each mutant has a distinct effect on PLN function and SR calcium homeostasis. Arg(9)-Cys and Arg(9)-Leu do not inhibit SERCA, Arg(14)-deletion is a partial inhibitor, and Arg(9)-His is comparable to wild-type. While the mutants have distinct functional effects on SERCA, they have in common that they cannot be phosphorylated by protein kinase A (PKA). Arg(9) and Arg(14) are required for PKA recognition and phosphorylation of PLN. Thus, mutations at these positions eliminate β-adrenergic control and dynamic cardiac contractility. Hydrophobic mutations of Arg(9) cause more complex changes in function, including loss of PLN function and dominant negative interaction with SERCA in heterozygous individuals. In addition, aberrant interaction with PKA may prevent phosphorylation of wild-type PLN and sequester PKA from other local subcellular targets. Herein we consider what is known about each mutant and how the synergistic changes in SR calcium homeostasis lead to impaired cardiac contractility and dilated cardiomyopathy.
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Dilated cardiomyopathy secondary to rickets-related hypocalcaemia: eight case reports and a review of the literature.
Yilmaz, O, Olgun, H, Ciftel, M, Kilic, O, Kartal, I, Iskenderoglu, NY, Laloglu, F, Ceviz, N
Cardiology in the young. 2015;(2):261-6
Abstract
INTRODUCTION Dilated cardiomyopathy is usually idiopathic and may arise secondary to infections or metabolic or genetic causes. Another rare cause is hypocalcaemia. Owing to the fact that calcium plays an essential role in excitation and contraction of myocardial muscle, myocardial contractility may decline in patients with hypocalcaemia. MATERIALS AND METHODS Patients with symptoms of congestive heart failure and rickets-related hypocalcaemia were assessed clinically and by echocardiography in a paediatric cardiology clinic. Echocardiography was performed for all patients. Rickets was diagnosed according to the clinical, laboratory, and radiologic findings. Maternal lifestyle and living conditions were investigated, and the maternal 25-OH vitamin D3 blood level was measured. RESULTS We evaluated eight patients who developed heart failure as a result of severe hypocalcaemia associated with rickets between August, 1999 and June, 2012. The age distribution of the patients was 3-12 months. Laboratory results were consistent with advanced-stage rickets. Severe hypocalcaemia was detected in all patients. The maternal 25-OH vitamin D3 levels were low. Echocardiography revealed increased pre-treatment left ventricle end-systolic and end-diastolic diameters for age and reduced ejection fraction and fractional shortening. After clinical improvement, the patients were discharged. CONCLUSIONS Severe hypocalcaemia associated with rickets must always be kept in mind among the causes of dilated cardiomyopathy and impaired cardiac function in infants. If diagnosed and treated in time, dilated cardiomyopathy and severe heart failure related to rickets respond well.
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[Update on cardiac SCN5A gene mutation and dilated cardiomyopathy].
Sun, LP, Wang, RX
Zhonghua xin xue guan bing za zhi. 2011;(2):182-4
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Contribution of genetic factors to the pathogenesis of dilated cardiomyopathy: the cause of dilated cardiomyopathy: genetic or acquired? (genetic-side).
Kimura, A
Circulation journal : official journal of the Japanese Circulation Society. 2011;(7):1756-65; discussion 1765
Abstract
Dilated cardiomyopathy (DCM) is characterized by dilated ventricles and systolic dysfunction. Its etiology is not fully unraveled, but both extrinsic and intrinsic factors are considered to be involved. The intrinsic factors include genetic variations in the genes (ie, disease-causing mutations and disease-associated polymorphisms), which play key roles in controlling the susceptibility to the disease by affecting the performance, regulation, and/or maintenance of cardiac function. DCM can be classified into 2 types: hereditary and non-hereditary. The genetic variations, or disease-causing mutations, contributing to the pathogenesis of hereditary DCM can be found in various genes, especially those for sarcolemma elements, contractile elements, Z-disc elements, sarcoplasmic elements, and nuclear lamina elements of cardiomyocytes. On the other hand, disease-associated polymorphisms, which control the susceptibility to non-hereditary DCM, may be found in genes expressing not only in cardiomyocytes but also other non-cardiac cells involved in the immune system. Because functional alterations caused by these genetic variations can be classified into several categories, it is necessary to understand the pathogenesis and hence to develop diagnostic and therapeutic strategies for both hereditary and non-hereditary DCM from the viewpoint of genetic factors.
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Laminopathies: multisystem dystrophy syndromes.
Jacob, KN, Garg, A
Molecular genetics and metabolism. 2006;(4):289-302
Abstract
Laminopathies are a heterogeneous group of genetic disorders due to abnormalities in type A lamins and can manifest varied clinical features affecting many organs including the skeletal and cardiac muscle, adipose tissue, nervous system, cutaneous tissue, and bone. Mutations in the gene encoding lamins A and C (LMNA) cause primary laminopathies, including various types of lipodystrophies, muscular dystrophies and progeroid syndromes, mandibuloacral dysplasia, dilated cardiomyopathies, and restrictive dermopathy. The secondary laminopathies are due to mutations in ZMPSTE24 gene which encodes for a zinc metalloproteinase involved in processing of prelamin A into mature lamin A and cause mandibuloacral dysplasia and restrictive dermopathy. Skin fibroblast cells from many patients with laminopathies show a range of abnormal nuclear morphology including bleb formation, honeycombing, and presence of multi-lobulated nuclei. The mechanisms by which mutations in LMNA gene cause multisystem dystrophy are an active area of current investigation. Further studies are needed to understand the underlying mechanisms of marked pleiotropy in laminopathies.
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Lethal cardiomyopathy in epidermolysis bullosa associated with amitriptyline.
Taibjee, SM, Ramani, P, Brown, R, Moss, C
Archives of disease in childhood. 2005;(8):871-2
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There are previous reports of dilated cardiomyopathy (DCM) in recessive dystrophic epidermolysis bullosa (RDEB), a debilitating blistering skin disorder. The pathogenesis of DCM in RDEB remains uncertain, although dietary deficiency of selenium and carnitine have been implicated. A 6 year old girl with RDEB who died of DCM is reported; attention is drawn to the possible role of two potentially cardiotoxic drugs, amitriptyline and cisapride.
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[Diseases associated with lamin A/C gene defects: what the clinical cardiologist ought to know].
Pasotti, M, Repetto, A, Pisani, A, Arbustini, E
Italian heart journal. Supplement : official journal of the Italian Federation of Cardiology. 2004;(2):98-111
Abstract
The nuclear lamina is a proteinaceous layer apposed to the inner nuclear membrane. It is composed of a family of polypeptides, the lamins, highly conserved in evolution. In mammals, 3 lamins, A, B and C have been described with molecular weights ranging from 60,000 to 78,000 Da. Lamins A and C have close sequence homology. Lamins can be classified with the intermediate filament polypeptides and consist of a central rod domain flanked by globular and carboxyl domains. Lamins are synthesized into the cytoplasm: lamins B and C are transported from the cytoplasm into the nucleus and their sequences are not cleaved but remain a permanent feature of the mature polypeptide. Vice versa, lamin A is not synthesized as a large precursor polypeptide. The lamin A/C gene (LMNA) is mapped to 1q21.2-q21.3. Lamins are expressed in a wide range of tissues, including adult heart and skeletal muscle. Naturally occurring mutations in LMNA have been shown to be responsible for distinct diseases called laminopathies, including dilated cardiomyopathy with or without conduction defect and with or without variable skeletal muscle involvement. In the cardiological setting, conduction defects associated with dilated cardiomyopathy are now a reliable marker for LMNA gene molecular screening.