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Popa IP, Șerban DN, Mărănducă MA, Șerban IL, Tamba BI, Tudorancea I. Brugada Syndrome: From Molecular Mechanisms and Genetics to Risk Stratification. Int J Mol Sci 2023; 24:ijms24043328. [PMID: 36834739 PMCID: PMC9967917 DOI: 10.3390/ijms24043328] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Revised: 01/13/2023] [Accepted: 02/06/2023] [Indexed: 02/11/2023] Open
Abstract
Brugada syndrome (BrS) is a rare hereditary arrhythmia disorder, with a distinctive ECG pattern, correlated with an increased risk of ventricular arrhythmias and sudden cardiac death (SCD) in young adults. BrS is a complex entity in terms of mechanisms, genetics, diagnosis, arrhythmia risk stratification, and management. The main electrophysiological mechanism of BrS requires further research, with prevailing theories centered on aberrant repolarization, depolarization, and current-load match. Computational modelling, pre-clinical, and clinical research show that BrS molecular anomalies result in excitation wavelength (k) modifications, which eventually increase the risk of arrhythmia. Although a mutation in the SCN5A (Sodium Voltage-Gated Channel Alpha Subunit 5) gene was first reported almost two decades ago, BrS is still currently regarded as a Mendelian condition inherited in an autosomal dominant manner with incomplete penetrance, despite the recent developments in the field of genetics and the latest hypothesis of additional inheritance pathways proposing a more complex mode of inheritance. In spite of the extensive use of the next-generation sequencing (NGS) technique with high coverage, genetics remains unexplained in a number of clinically confirmed cases. Except for the SCN5A which encodes the cardiac sodium channel NaV1.5, susceptibility genes remain mostly unidentified. The predominance of cardiac transcription factor loci suggests that transcriptional regulation is essential to the Brugada syndrome's pathogenesis. It appears that BrS is a multifactorial disease, which is influenced by several loci, each of which is affected by the environment. The primary challenge in individuals with a BrS type 1 ECG is to identify those who are at risk for sudden death, researchers propose the use of a multiparametric clinical and instrumental strategy for risk stratification. The aim of this review is to summarize the latest findings addressing the genetic architecture of BrS and to provide novel perspectives into its molecular underpinnings and novel models of risk stratification.
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Affiliation(s)
- Irene Paula Popa
- Cardiology Clinic, “St. Spiridon” County Clinical Emergency Hospital, 700111 Iași, Romania
| | - Dragomir N. Șerban
- Department of Physiology, “Grigore T. Popa” University of Medicine and Pharmacy, 700115 Iași, Romania
| | - Minela Aida Mărănducă
- Department of Physiology, “Grigore T. Popa” University of Medicine and Pharmacy, 700115 Iași, Romania
| | - Ionela Lăcrămioara Șerban
- Department of Physiology, “Grigore T. Popa” University of Medicine and Pharmacy, 700115 Iași, Romania
| | - Bogdan Ionel Tamba
- Department of Pharmacology, “Grigore T. Popa” University of Medicine and Pharmacy, 700115 Iași, Romania
- Correspondence:
| | - Ionuț Tudorancea
- Cardiology Clinic, “St. Spiridon” County Clinical Emergency Hospital, 700111 Iași, Romania
- Department of Physiology, “Grigore T. Popa” University of Medicine and Pharmacy, 700115 Iași, Romania
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Monasky MM, Micaglio E, D'Imperio S, Pappone C. The Mechanism of Ajmaline and Thus Brugada Syndrome: Not Only the Sodium Channel! Front Cardiovasc Med 2022; 8:782596. [PMID: 35004896 PMCID: PMC8733296 DOI: 10.3389/fcvm.2021.782596] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Accepted: 11/29/2021] [Indexed: 12/12/2022] Open
Abstract
Ajmaline is an anti-arrhythmic drug that is used to unmask the type-1 Brugada syndrome (BrS) electrocardiogram pattern to diagnose the syndrome. Thus, the disease is defined at its core as a particular response to this or other drugs. Ajmaline is usually described as a sodium-channel blocker, and most research into the mechanism of BrS has centered around this idea that the sodium channel is somehow impaired in BrS, and thus the genetics research has placed much emphasis on sodium channel gene mutations, especially the gene SCN5A, to the point that it has even been suggested that only the SCN5A gene should be screened in BrS patients. However, pathogenic rare variants in SCN5A are identified in only 20–30% of cases, and recent data indicates that SCN5A variants are actually, in many cases, prognostic rather than diagnostic, resulting in a more severe phenotype. Furthermore, the misconception by some that ajmaline only influences the sodium current is flawed, in that ajmaline actually acts additionally on potassium and calcium currents, as well as mitochondria and metabolic pathways. Clinical studies have implicated several candidate genes in BrS, encoding not only for sodium, potassium, and calcium channel proteins, but also for signaling-related, scaffolding-related, sarcomeric, and mitochondrial proteins. Thus, these proteins, as well as any proteins that act upon them, could prove absolutely relevant in the mechanism of BrS.
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Affiliation(s)
- Michelle M Monasky
- Arrhythmology Department, IRCCS Policlinico San Donato, San Donato Milanese, Milan, Italy
| | - Emanuele Micaglio
- Arrhythmology Department, IRCCS Policlinico San Donato, San Donato Milanese, Milan, Italy
| | - Sara D'Imperio
- Arrhythmology Department, IRCCS Policlinico San Donato, San Donato Milanese, Milan, Italy
| | - Carlo Pappone
- Arrhythmology Department, IRCCS Policlinico San Donato, San Donato Milanese, Milan, Italy.,Vita-Salute San Raffaele University, Milan, Italy
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Monasky MM, Rutigliani C, Micaglio E, Pappone C. Commentary: Peptide-Based Targeting of the L-Type Calcium Channel Corrects the Loss-of-Function Phenotype of Two Novel Mutations of the CACNA1 Gene Associated With Brugada Syndrome. Front Physiol 2021; 12:682567. [PMID: 34177625 PMCID: PMC8220137 DOI: 10.3389/fphys.2021.682567] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Accepted: 05/10/2021] [Indexed: 01/27/2023] Open
Affiliation(s)
- Michelle M Monasky
- Arrhythmology Department, IRCCS Policlinico San Donato, San Donato Milanese, Milan, Italy
| | | | - Emanuele Micaglio
- Arrhythmology Department, IRCCS Policlinico San Donato, San Donato Milanese, Milan, Italy
| | - Carlo Pappone
- Arrhythmology Department, IRCCS Policlinico San Donato, San Donato Milanese, Milan, Italy.,Vita-Salute San Raffaele University, Milan, Italy
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Pappone C, Ciconte G, Micaglio E, Monasky MM. Common modulators of Brugada syndrome phenotype do not affect SCN5A prognostic value. Eur Heart J 2021; 42:1273-1274. [PMID: 33595071 PMCID: PMC8014514 DOI: 10.1093/eurheartj/ehab071] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Affiliation(s)
- Carlo Pappone
- Arrhythmia and Electrophysiology Department, IRCCS Policlinico San Donato, Piazza E. Malan 1, 20097 San Donato Milanese, Milan, Italy.,Vita-Salute San Raffaele University, Milan, Italy
| | - Giuseppe Ciconte
- Arrhythmia and Electrophysiology Department, IRCCS Policlinico San Donato, Piazza E. Malan 1, 20097 San Donato Milanese, Milan, Italy
| | - Emanuele Micaglio
- Arrhythmia and Electrophysiology Department, IRCCS Policlinico San Donato, Piazza E. Malan 1, 20097 San Donato Milanese, Milan, Italy
| | - Michelle M Monasky
- Arrhythmia and Electrophysiology Department, IRCCS Policlinico San Donato, Piazza E. Malan 1, 20097 San Donato Milanese, Milan, Italy
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Monasky MM, Micaglio E, Locati ET, Pappone C. Evaluating the Use of Genetics in Brugada Syndrome Risk Stratification. Front Cardiovasc Med 2021; 8:652027. [PMID: 33969014 PMCID: PMC8096997 DOI: 10.3389/fcvm.2021.652027] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Accepted: 03/24/2021] [Indexed: 12/19/2022] Open
Abstract
The evolution of the current dogma surrounding Brugada syndrome (BrS) has led to a significant debate about the real usefulness of genetic testing in this syndrome. Since BrS is defined by a particular electrocardiogram (ECG) pattern, after ruling out certain possible causes, this disease has come to be defined more for what it is not than for what it is. Extensive research is required to understand the effects of specific individual variants, including modifiers, rather than necessarily grouping together, for example, “all SCN5A variants” when trying to determine genotype-phenotype relationships, because not all variants within a particular gene act similarly. Genetic testing, including whole exome or whole genome testing, and family segregation analysis should always be performed when possible, as this is necessary to advance our understanding of the genetics of this condition. All considered, BrS should no longer be considered a pure autosomal dominant disorder, but an oligogenic condition. Less common patterns of inheritance, such as recessive, X–linked, or mitochondrial may exist. Genetic testing, in our opinion, should not be used for diagnostic purposes. However, variants in SCN5A can have a prognostic value. Patients should be diagnosed and treated per the current guidelines, after an arrhythmologic examination, based on the presence of the specific BrS ECG pattern. The genotype characterization should come in a second stage, particularly in order to guide the familial diagnostic work-up. In families in which an SCN5A pathogenic variant is found, genetic testing could possibly contribute to the prognostic risk stratification.
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Affiliation(s)
| | - Emanuele Micaglio
- Arrhythmology Department, IRCCS Policlinico San Donato, Milan, Italy
| | - Emanuela T Locati
- Arrhythmology Department, IRCCS Policlinico San Donato, Milan, Italy
| | - Carlo Pappone
- Arrhythmology Department, IRCCS Policlinico San Donato, Milan, Italy.,Vita-Salute San Raffaele University, Milan, Italy
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Novel SCN5A p.V1429M Variant Segregation in a Family with Brugada Syndrome. Int J Mol Sci 2020; 21:ijms21165902. [PMID: 32824506 PMCID: PMC7460631 DOI: 10.3390/ijms21165902] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Revised: 08/11/2020] [Accepted: 08/12/2020] [Indexed: 01/10/2023] Open
Abstract
Brugada syndrome (BrS) is diagnosed by the presence of an elevated ST-segment and can result in sudden cardiac death. The most commonly found mutated gene is SCN5A, which some argue is the only gene that has been definitively confirmed to cause BrS, while the potential causative effect of other genes is still under debate. While the issue of BrS genetics is currently a hot topic, current knowledge is not able to result in molecular confirmation of over half of BrS cases. Therefore, it is difficult to develop research models with wide potential. Instead, the clinical genetics first need to be better understood. In this study, we provide crucial human data on the novel heterozygous variant NM_198056.2:c.4285G>A (p.Val1429Met) in the SCN5A gene, and demonstrate its segregation with BrS, suggesting a pathogenic effect. These results provide the first disease association with this variant and are crucial clinical data to communicate to basic scientists, who could perform functional studies to better understand the molecular effects of this clinically-relevant variant in BrS.
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