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Cardiovascular Involvement in Pediatric FLNC Variants: A Case Series of Fourteen Patients. J Cardiovasc Dev Dis 2022; 9:jcdd9100332. [PMID: 36286284 PMCID: PMC9604120 DOI: 10.3390/jcdd9100332] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2022] [Accepted: 09/22/2022] [Indexed: 11/16/2022] Open
Abstract
Filamin C is a protein specifically expressed in myocytes and cardiomyocytes and is involved in several biological functions, including sarcomere contractile activity, signaling, cellular adhesion, and repair. FLNC variants are associated with different disorders ranging from striated muscle (myofibrillar distal or proximal) myopathy to cardiomyopathies (CMPs) (restrictive, hypertrophic, and dilated), or both. The outcome depends on functional consequences of the detected variants, which result either in FLNC haploinsufficiency or in an aberrant protein, the latter affecting sarcomere structure leading to protein aggregates. Cardiac manifestations of filaminopathies are most often described as adult onset CMPs and limited reports are available in children or on other cardiac spectrums (congenital heart defects-CHDs, or arrhythmias). Here we report on 13 variants in 14 children (2.8%) out of 500 pediatric patients with early-onset different cardiac features ranging from CMP to arrhythmias and CHDs. In one patient, we identified a deletion encompassing FLNC detected by microarray, which was overlooked by next generation sequencing. We established a potential genotype-phenotype correlation of the p.Ala1186Val variant in severe and early-onset restrictive cardiomyopathy (RCM) associated with a limb-girdle defect (two new patients in addition to the five reported in the literature). Moreover, in three patients (21%), we identified a relatively frequent finding of long QT syndrome (LQTS) associated with RCM (n = 2) and a hypertrabeculated left ventricle (n = 1). RCM and LQTS in children might represent a specific red flag for FLNC variants. Further studies are warranted in pediatric cohorts to delineate potential expanding phenotypes related to FLNC.
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Abstract
The number of therapies for heart failure (HF) with reduced ejection fraction has nearly doubled in the past decade. In addition, new therapies for HF caused by hypertrophic and infiltrative disease are emerging rapidly. Indeed, we are on the verge of a new era in HF in which insights into the biology of myocardial disease can be matched to an understanding of the genetic predisposition in an individual patient to inform precision approaches to therapy. In this Review, we summarize the biology of HF, emphasizing the causal relationships between genetic contributors and traditional structure-based remodelling outcomes, and highlight the mechanisms of action of traditional and novel therapeutics. We discuss the latest advances in our understanding of both the Mendelian genetics of cardiomyopathy and the complex genetics of the clinical syndrome presenting as HF. In the phenotypic domain, we discuss applications of machine learning for the subcategorization of HF in ways that might inform rational prescribing of medications. We aim to bridge the gap between the biology of the failing heart, its diverse clinical presentations and the range of medications that we can now use to treat it. We present a roadmap for the future of precision medicine in HF.
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Al-Shafai KN, Al-Hashemi M, Manickam C, Musa R, Selvaraj S, Syed N, Vempalli F, Ali M, Yacoub M, Estivill X. Genetic evaluation of cardiomyopathies in Qatar identifies enrichment of pathogenic sarcomere gene variants and possible founder disease mutations in the Arabs. Mol Genet Genomic Med 2021; 9:e1709. [PMID: 34137518 PMCID: PMC8372065 DOI: 10.1002/mgg3.1709] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2020] [Revised: 09/03/2020] [Accepted: 05/04/2021] [Indexed: 01/20/2023] Open
Abstract
Background Hypertrophic cardiomyopathy (HCM) and dilated cardiomyopathy (DCM) are serious inherited heart diseases with various causative mutations identified. The full spectrum of causative mutations remains to be discovered, especially in understudied populations. Methods Here, we established the DOHA Registry and Biobank for cardiomyopathies in Qatar, followed by sequencing of 174 genes on 51 HCM and 53 DCM patients, and 31 relatives. Results In HCM, the analysis of 25 HCM‐associated genes showed that 20% of HCM cases had putative pathogenic variants for cardiomyopathy, mainly in sarcomere genes. Additional 49% of HCM cases had variants of uncertain significance, while 31% of HCM cases had likely benign variant(s) or had no variants identified within the analyzed HCM genes. In DCM, 56 putative DCM genes were analyzed. Eight percent of DCM cases had putative pathogenic variants for DCM, in the TTN gene while 70% of cases had variants of uncertain significance, in the analyzed DCM genes, that will need further pathogenicity assessment. Moreover, 22% of DCM cases remain unexplained, by having likely benign variant(s) or having no variants detected in any of the analyzed DCM genes. Conclusion We identified or replicated at least four recurrent variants among cardiomyopathy patients, which could be founder disease mutations in the Arabic population, including a frameshift variant (c.1371_1381dupTATCCAGTTAT) of unknown significance in the FKTN gene which seems to cause DCM in homozygosity, and HCM in heterozygosity. In vivo and/or in vitro functional validation need to be pursued in order to assess the pathogenicity of the identified variants.
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Affiliation(s)
- Kholoud N Al-Shafai
- College of Health and Life Sciences, Hamad Bin Khalifa University, Doha, Qatar.,Sidra Research Department, Sidra Medicine, Doha, Qatar
| | | | | | - Rania Musa
- The Heart Hospital, Hamad Medical Corporation, Doha, Qatar
| | | | - Najeeb Syed
- Sidra Research Department, Sidra Medicine, Doha, Qatar
| | | | - Muneera Ali
- The Heart Hospital, Hamad Medical Corporation, Doha, Qatar
| | - Magdi Yacoub
- National Heart and Lung Institute, Imperial College London, London, UK
| | - Xavier Estivill
- College of Health and Life Sciences, Hamad Bin Khalifa University, Doha, Qatar.,Sidra Research Department, Sidra Medicine, Doha, Qatar.,Quantitative Genomics Laboratories (qGenomics, Barcelona, Spain
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Schänzer A, Schumann E, Zengeler D, Gulatz L, Maroli G, Ahting U, Sprengel A, Gräf S, Hahn A, Jux C, Acker T, Fürst DO, Rupp S, Schuld J, van der Ven PFM. The p.Ala2430Val mutation in filamin C causes a "hypertrophic myofibrillar cardiomyopathy". J Muscle Res Cell Motil 2021; 42:381-397. [PMID: 33710525 DOI: 10.1007/s10974-021-09601-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Accepted: 02/26/2021] [Indexed: 10/21/2022]
Abstract
Hypertrophic cardiomyopathy (HCM) often leads to heart failure. Mutations in sarcomeric proteins are most frequently the cause of HCM but in many patients the gene defect is not known. Here we report on a young man who was diagnosed with HCM shortly after birth. Whole exome sequencing revealed a mutation in the FLNC gene (c.7289C > T; p.Ala2430Val) that was previously shown to cause aggregation of the mutant protein in transfected cells. Myocardial tissue from patients with this mutation has not been analyzed before and thus, the underlying etiology is not well understood. Myocardial tissue of our patient obtained during myectomy at the age of 23 years was analyzed in detail by histochemistry, immunofluorescence staining, electron microscopy and western blot analysis. Cardiac histology showed a pathology typical for myofibrillar myopathy with myofibril disarray and abnormal protein aggregates containing BAG3, desmin, HSPB5 and filamin C. Analysis of sarcomeric and intercalated disc proteins showed focally reduced expression of the gap junction protein connexin43 and Xin-positive sarcomeric lesions in the cardiomyocytes of our patient. In addition, autophagy pathways were altered with upregulation of LC3-II, WIPI1 and HSPB5, 6, 7 and 8. We conclude that the p.Ala2430Val mutation in FLNC most probably is associated with HCM characterized by abnormal intercalated discs, disarray of myofibrils and aggregates containing Z-disc proteins similar to myofibrillar myopathy, which supports the pathological effect of the mutation.
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Affiliation(s)
- Anne Schänzer
- Institute of Neuropathology, Justus Liebig University, Arndstr.16, 35392, Giessen, Germany.
| | - Elisabeth Schumann
- Institute of Neuropathology, Justus Liebig University, Arndstr.16, 35392, Giessen, Germany
| | - Diana Zengeler
- Center for Genomics and Transcriptomics (CeGat) GmbH, Tübingen, Germany
| | - Lisann Gulatz
- Institute of Neuropathology, Justus Liebig University, Arndstr.16, 35392, Giessen, Germany
| | - Giovanni Maroli
- Department of Cardiac Development and Remodeling, Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany
| | - Uwe Ahting
- Institute of Human Genetics, Technical University of Munich (TUM), Munich, Germany
| | - Anke Sprengel
- Pediatric Heart Center, Justus Liebig University, Giessen, Germany
| | - Sabine Gräf
- Institute of Neuropathology, Justus Liebig University, Arndstr.16, 35392, Giessen, Germany
| | - Andreas Hahn
- Department of Child Neurology, Justus Liebig University, Giessen, Germany
| | - Christian Jux
- Pediatric Heart Center, Justus Liebig University, Giessen, Germany
| | - Till Acker
- Institute of Neuropathology, Justus Liebig University, Arndstr.16, 35392, Giessen, Germany
| | - Dieter O Fürst
- Department of Molecular Cell Biology, Institute for Cell Biology, University of Bonn, Bonn, Germany
| | - Stefan Rupp
- Pediatric Heart Center, Justus Liebig University, Giessen, Germany
| | - Julia Schuld
- Department of Molecular Cell Biology, Institute for Cell Biology, University of Bonn, Bonn, Germany
| | - Peter F M van der Ven
- Department of Molecular Cell Biology, Institute for Cell Biology, University of Bonn, Bonn, Germany
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An Investigation of Fibulin-2 in Hypertrophic Cardiomyopathy. Int J Mol Sci 2020; 21:ijms21197176. [PMID: 33003281 PMCID: PMC7583916 DOI: 10.3390/ijms21197176] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Revised: 09/20/2020] [Accepted: 09/22/2020] [Indexed: 11/17/2022] Open
Abstract
Hypertrophic cardiomyopathy (HCM) is the most common inherited heart muscle disease, with a prevalence of at least 1 in 500 in the general population. The disease is pleiotropic and is characterized by an increased stiffness of the myocardium, partly due to changes in the extracellular matrix (ECM), with elevated levels of interstitial fibrosis. Myocardial fibrosis is linked to impaired diastolic function and possibly phenotypic heterogeneity of HCM. The ECM consists of a very large number of proteins, which actively interact with each other as well as with myocardial cells. The role of other multiple components of the ECM in HCM has not been defined. Fibulin-2 is a glycoprotein component of the ECM, which plays an important role during embryogenesis of the heart; however, its role in adult myocardium has not been adequately studied. We here describe, for the first time, abnormal expression of fibulin-2 in the myocardium in patients with HCM as compared to normal controls. This abnormal expression was localized in the cytoplasm of myocardial cells and in the interstitial fibroblasts. In addition, fibulin-2 levels, measured by ELISA, were significantly elevated in the serum of patients with HCM as compared to normal controls.
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Rehmani T, Salih M, Tuana BS. Cardiac-Specific Cre Induces Age-Dependent Dilated Cardiomyopathy (DCM) in Mice. Molecules 2019; 24:molecules24061189. [PMID: 30917606 PMCID: PMC6471127 DOI: 10.3390/molecules24061189] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Revised: 03/18/2019] [Accepted: 03/19/2019] [Indexed: 11/16/2022] Open
Abstract
The genetic modification of the mouse genome using the cre-lox system has been an invaluable tool in deciphering gene and protein function in a temporal and/or spatial manner. However, it has its pitfalls, as researchers have shown that the unregulated expression of cre recombinase can cause DNA damage, the consequences of which can be very detrimental to mouse health. Previously published literature on the most utilized cardiac-specific cre, αMHC-cre, mouse model exhibited a nonlethal hypertrophic cardiomyopathy (HCM) with aging. However, using the same αMHC-cre mice, we observed a cardiac pathology, resulting in complete lethality by 11 months of age. Echocardiography and histology revealed that the αMHC-cre mice were displaying symptoms of dilated cardiomyopathy (DCM) by seven months of age, which ultimately led to their demise in the absence of any HCM at any age. Molecular analysis showed that this phenotype was associated with the DNA damage response through the downregulation of activated p38 and increased expression of JNK, p53, and Bax, known inducers of myocyte death resulting in fibrosis. Our data urges strong caution when interpreting the phenotypic impact of gene responses using αMHC-cre mice, since a lethal DCM was induced by the cre driver in an age-dependent manner in this commonly utilized model system.
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Affiliation(s)
- Taha Rehmani
- Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, Ottawa, ON K1H 8M5, Canada.
| | - Maysoon Salih
- Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, Ottawa, ON K1H 8M5, Canada.
| | - Balwant S Tuana
- Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, Ottawa, ON K1H 8M5, Canada.
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Karamichalis JM, Aguib H, Anastasopulos A, Yacoub M. Surgical relief of left ventricular outflow obstruction in pediatric hypertrophic cardiomyopathy: The need for a tailored approach. J Thorac Cardiovasc Surg 2018; 156:2283-2284. [PMID: 30268570 DOI: 10.1016/j.jtcvs.2018.08.015] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Revised: 08/08/2018] [Accepted: 08/16/2018] [Indexed: 02/02/2023]
Affiliation(s)
- John M Karamichalis
- Pediatric Cardiac Surgery, The Children's Hospital at Saint Francis, Tulsa, Okla; Pediatric Cardiac Surgery, Arkansas Children's Hospital, Little Rock, Ark.
| | - Heba Aguib
- Biomedical Engineering and Innovation Laboratory, Aswan Heart Centre, Magdi Yacoub Foundation, Aswan, Egypt; Harefield Heart Science Centre, National Heart & Lung Institute, Imperial College London, London, United Kingdom
| | | | - Magdi Yacoub
- Biomedical Engineering and Innovation Laboratory, Aswan Heart Centre, Magdi Yacoub Foundation, Aswan, Egypt; Harefield Heart Science Centre, National Heart & Lung Institute, Imperial College London, London, United Kingdom
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Ehsan M, Jiang H, L Thomson K, Gehmlich K. When signalling goes wrong: pathogenic variants in structural and signalling proteins causing cardiomyopathies. J Muscle Res Cell Motil 2017; 38:303-316. [PMID: 29119312 PMCID: PMC5742121 DOI: 10.1007/s10974-017-9487-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2017] [Accepted: 10/28/2017] [Indexed: 12/20/2022]
Abstract
Cardiomyopathies are a diverse group of cardiac disorders with distinct phenotypes, depending on the proteins and pathways affected. A substantial proportion of cardiomyopathies are inherited and those will be the focus of this review article. With the wide application of high-throughput sequencing in the practice of clinical genetics, the roles of novel genes in cardiomyopathies are recognised. Here, we focus on a subgroup of cardiomyopathy genes [TTN, FHL1, CSRP3, FLNC and PLN, coding for Titin, Four and a Half LIM domain 1, Muscle LIM Protein, Filamin C and Phospholamban, respectively], which, despite their diverse biological functions, all have important signalling functions in the heart, suggesting that disturbances in signalling networks can contribute to cardiomyopathies.
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Affiliation(s)
- Mehroz Ehsan
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine and British Heart Foundation Centre of Research Excellence, University of Oxford, Oxford, UK
| | - He Jiang
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine and British Heart Foundation Centre of Research Excellence, University of Oxford, Oxford, UK
| | - Kate L Thomson
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine and British Heart Foundation Centre of Research Excellence, University of Oxford, Oxford, UK
| | - Katja Gehmlich
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine and British Heart Foundation Centre of Research Excellence, University of Oxford, Oxford, UK.
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Yacoub MH, Afifi A, Saad H, Aguib H, ElGuindy A. Current state of the art and future of myectomy. Ann Cardiothorac Surg 2017; 6:307-317. [PMID: 28944171 DOI: 10.21037/acs.2017.06.04] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Surgical relief of left ventricular outflow tract obstruction (LVOTO) in hypertrophic cardiomyopathy (HCM) requires more than septal myectomy. The procedure is currently the gold standard for all symptomatic HCM patients except those with comorbidities. The operation requires an individualized approach to restore the sophisticated functions of the left ventricular outflow tract (LVOT) without injury to the surrounding vital structures. The procedure should be tailored to deal with all the varied components of the obstruction including fibrous trigones, accessory tissues, and papillary muscle fusion. Preoperative multimodality imaging and numerical modeling combined with intraoperative transesophageal echocardiography (TEE) are essential to define existing anomalies as well as assess the adequacy of the repair. The mitral valve can be conserved in virtually all patients. The operation can be conducted with very low mortality and morbidity with predictable good outcomes both in the short and long term. Nevertheless, surgical relief of LVOTO is still grossly underused.
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Affiliation(s)
- Magdi H Yacoub
- National Heart and Lung Institute, Imperial College London, London, UK.,Aswan Heart Centre, Aswan Governorate, Egypt
| | - Ahmed Afifi
- Aswan Heart Centre, Aswan Governorate, Egypt
| | - Hesham Saad
- Aswan Heart Centre, Aswan Governorate, Egypt
| | - Heba Aguib
- National Heart and Lung Institute, Imperial College London, London, UK.,Aswan Heart Centre, Aswan Governorate, Egypt
| | - Ahmed ElGuindy
- National Heart and Lung Institute, Imperial College London, London, UK.,Aswan Heart Centre, Aswan Governorate, Egypt
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Sanoudou D, Kolokathis F, Arvanitis D, Al-Shafai K, Krishnamoorthy N, Buchan RJ, Walsh R, Tsiapras D, Barton PJ, Cook SA, Kremastinos D, Yacoub M. Genetic modifiers to the PLN L39X mutation in a patient with DCM and sustained ventricular tachycardia? Glob Cardiol Sci Pract 2015; 2015:29. [PMID: 26535225 PMCID: PMC4614339 DOI: 10.5339/gcsp.2015.29] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2015] [Accepted: 04/30/2015] [Indexed: 11/03/2022] Open
Affiliation(s)
- Despina Sanoudou
- 4 Dept. of Internal Medicine, Medical School, University of Athens, Greece. ; Biomedical Research Foundation of the Academy of Athens, Greece
| | | | | | - Kholoud Al-Shafai
- Qatar Cardiovascular Research Center (QCRC), Qatar Foundation, Doha, Qatar
| | | | - Rachel J Buchan
- NIHR Cardiovascular Biomedical Research Unit, Royal Brompton and Harefield NHS Foundation Trust, London, UK. ; National Heart & Lung Institute, Imperial College London, London, UK
| | - Roddy Walsh
- NIHR Cardiovascular Biomedical Research Unit, Royal Brompton and Harefield NHS Foundation Trust, London, UK. ; National Heart & Lung Institute, Imperial College London, London, UK
| | | | - Paul Jr Barton
- NIHR Cardiovascular Biomedical Research Unit, Royal Brompton and Harefield NHS Foundation Trust, London, UK. ; National Heart & Lung Institute, Imperial College London, London, UK
| | - Stuart A Cook
- NIHR Cardiovascular Biomedical Research Unit, Royal Brompton and Harefield NHS Foundation Trust, London, UK. ; National Heart & Lung Institute, Imperial College London, London, UK. ; NIHR Cardiovascular Biomedical Research Unit, Royal Brompton and Harefield NHS Foundation Trust, London, UK
| | | | - Magdi Yacoub
- Qatar Cardiovascular Research Center (QCRC), Qatar Foundation, Doha, Qatar. ; NIHR Cardiovascular Biomedical Research Unit, Royal Brompton and Harefield NHS Foundation Trust, London, UK
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