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Hall CL, Akhtar MM, Sabater-Molina M, Futema M, Asimaki A, Protonotarios A, Dalageorgou C, Pittman AM, Suarez MP, Aguilera B, Molina P, Zorio E, Hernández JP, Pastor F, Gimeno JR, Syrris P, McKenna WJ. Filamin C variants are associated with a distinctive clinical and immunohistochemical arrhythmogenic cardiomyopathy phenotype. Int J Cardiol 2019; 307:101-108. [PMID: 31627847 DOI: 10.1016/j.ijcard.2019.09.048] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/11/2019] [Revised: 08/13/2019] [Accepted: 09/18/2019] [Indexed: 12/11/2022]
Abstract
BACKGROUND Pathogenic variants in the filamin C (FLNC) gene are associated with inherited cardiomyopathies including dilated cardiomyopathy with an arrhythmogenic phenotype. We evaluated FLNC variants in arrhythmogenic cardiomyopathy (ACM) and investigated the disease mechanism at a molecular level. METHODS 120 gene-elusive ACM patients who fulfilled diagnostic criteria for arrhythmogenic right ventricular cardiomyopathy (ARVC) were screened by whole exome sequencing. Fixed cardiac tissue from FLNC variant carriers who had died suddenly was investigated by histology and immunohistochemistry. RESULTS Novel or rare FLNC variants, four null and five variants of unknown significance, were identified in nine ACM probands (7.5%). In FLNC null variant carriers (including family members, n = 16) Task Force diagnostic electrocardiogram repolarization/depolarization abnormalities were uncommon (19%), echocardiography was normal in 69%, while 56% had >500 ventricular ectopics/24 h or ventricular tachycardia on Holter and 67% had late gadolinium enhancement (LGE) on cardiac magnetic resonance imaging (CMRI). Ten gene positive individuals (63%) had abnormalities on ECG or CMRI that are not included in the current diagnostic criteria for ARVC. Immunohistochemistry showed altered key protein distribution, distinctive from that observed in ARVC, predominantly in the left ventricle. CONCLUSIONS ACM associated with FLNC variants presents with a distinctive phenotype characterized by Holter arrhythmia and LGE on CMRI with unremarkable ECG and echocardiographic findings. Clinical presentation in asymptomatic mutation carriers at risk of sudden death may include abnormalities which are currently non-diagnostic for ARVC. At the molecular level, the pathogenic mechanism related to FLNC appears different to classic forms of ARVC caused by desmosomal mutations.
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Affiliation(s)
- Charlotte L Hall
- Centre for Heart Muscle Disease, Institute of Cardiovascular Science, University College London, London, UK
| | - Mohammed M Akhtar
- Centre for Heart Muscle Disease, Institute of Cardiovascular Science, University College London, London, UK
| | - Maria Sabater-Molina
- Laboratorio de Cardiogenética, Instituto Murciano de Investigación Biosanitaria and Universidad de Murcia, Murcia, Spain
| | - Marta Futema
- Centre for Heart Muscle Disease, Institute of Cardiovascular Science, University College London, London, UK
| | - Angeliki Asimaki
- Cardiology Clinical Academic Group, Molecular and Clinical Sciences Research Institute, St Georges University of London, London, UK
| | - Alexandros Protonotarios
- Centre for Heart Muscle Disease, Institute of Cardiovascular Science, University College London, London, UK
| | - Chrysoula Dalageorgou
- Centre for Heart Muscle Disease, Institute of Cardiovascular Science, University College London, London, UK
| | - Alan M Pittman
- Molecular and Clinical Sciences Research Institute, St Georges University of London, London, UK
| | - Mari Paz Suarez
- Instituto Nacional de Toxicologia y Ciencias Forenses de Madrid (INTCF), Madrid, Spain
| | - Beatriz Aguilera
- Instituto Nacional de Toxicologia y Ciencias Forenses de Madrid (INTCF), Madrid, Spain
| | - Pilar Molina
- Department of Pathology at the Instituto de Medicina Legal y Ciencias Forenses de Valencia (IMLCF-Valencia), Histology Unit at the Universitat de València, Research Group on Inherited Heart Diseases, Sudden Death and Mechanisms of Disease (CaFaMuSMe) from the Instituto de Investigación Sanitaria (IIS) La Fe, Valencia, Spain
| | - Esther Zorio
- Cardiology Department at Hospital Universitario y Politécnico La Fe and Research Group on Inherited Heart Diseases, Sudden Death and Mechanisms of Disease (CaFaMuSMe) from the Instituto de Investigación Sanitaria (IIS) La Fe, Valencia, Spain
| | | | - Francisco Pastor
- Servicio de Cardiologia del Hospital Universitario Virgen de la Arrixaca and Departamento de Medicina Interna de la Universidad de Murcia, Murcia, Spain
| | - Juan R Gimeno
- Hospital Universitario Virgen de la Arrixaca, Murcia, Spain
| | - Petros Syrris
- Centre for Heart Muscle Disease, Institute of Cardiovascular Science, University College London, London, UK.
| | - William J McKenna
- Centre for Heart Muscle Disease, Institute of Cardiovascular Science, University College London, London, UK
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