De Novo Mutation in the SCN5A Gene Associated with Brugada Syndrome
Background: Brugada syndrome (BrS) is a genetically determined cardiac electrical disorder, characterized by typical electrocardiography (ECG) alterations, and it is an arrhythmogenic syndrome that may lead to sudden cardiac death. The most common genotype found among BrS patients is caused by mutat...
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Cell Physiol Biochem Press GmbH & Co KG
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doaj-d9da9229cbd44cdcad6f1f4d0ac3c7182020-11-24T21:28:58ZengCell Physiol Biochem Press GmbH & Co KGCellular Physiology and Biochemistry1015-89871421-97782015-07-013662250226210.1159/000430189430189De Novo Mutation in the SCN5A Gene Associated with Brugada SyndromeLumin WangXiangyun MengZhiguang YuchiZhenghang ZhaoDehui XuDavid FedidaZhuren WangChen HuangBackground: Brugada syndrome (BrS) is a genetically determined cardiac electrical disorder, characterized by typical electrocardiography (ECG) alterations, and it is an arrhythmogenic syndrome that may lead to sudden cardiac death. The most common genotype found among BrS patients is caused by mutations in the SCN5A gene, which lead to a loss of function of the cardiac sodium (Na+) channel (Nav1.5) by different mechanisms. Methods: The assay of confocal laser microscopy and western blot were used to identify the expression and location of L812Q at the cell surface. Characterization of Nav1.5 L812Q mutant Na+ channels was text by patch-clamp recordings, and the PHYRE2 server was used to build a model for human Nav1.5 channel. Results: Here, we report that a novel missense SCN5A mutation, L812Q, localized in the DII-S4 transmembrane region of the Nav1.5 channel protein, was identified in an index patient who showed a typical BrS type-1 ECG phenotype. The mutation was absent in the patient's parents and brother. Heterologous expression of the wild-type (WT) and L812Q mutant Nav1.5 channels in human embryonic kidney cells (HEK293 cells) reveals that the mutation results in a reduction of Na+ current density as well as ∼20 mV hyperpolarizing shift of the voltage dependence of inactivation. The voltage dependence of activation and the time course for recovery from inactivation are not affected by the mutation. The hyperpolarizing shift of the voltage dependence of inactivation caused a reduction of the Na+ window current as well. In addition, western blot and confocal laser microscopy imaging experiments showed that the mutation causes fewer channel to be expressed at the membrane than WT channel. A large proportion of the mutant channels are retained in the cytoplasm, probably in the endoplasmic reticulum. Conclusion: The decrease of channel expression, hyperpolarizing shift of voltage dependence of inactivation, and a decline of Na+ window current caused by L812Q mutation lead to a reduction of Na+ current during the upstroke and the repolarization phases of cardiac action potential, which contribute to the development of BrS.http://www.karger.com/Article/FullText/430189SCN5ASodium Channel GatingBrugada SyndromeArrhythmiaCardiac depolarizationIon channel trafficking |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Lumin Wang Xiangyun Meng Zhiguang Yuchi Zhenghang Zhao Dehui Xu David Fedida Zhuren Wang Chen Huang |
spellingShingle |
Lumin Wang Xiangyun Meng Zhiguang Yuchi Zhenghang Zhao Dehui Xu David Fedida Zhuren Wang Chen Huang De Novo Mutation in the SCN5A Gene Associated with Brugada Syndrome Cellular Physiology and Biochemistry SCN5A Sodium Channel Gating Brugada Syndrome Arrhythmia Cardiac depolarization Ion channel trafficking |
author_facet |
Lumin Wang Xiangyun Meng Zhiguang Yuchi Zhenghang Zhao Dehui Xu David Fedida Zhuren Wang Chen Huang |
author_sort |
Lumin Wang |
title |
De Novo Mutation in the SCN5A Gene Associated with Brugada Syndrome |
title_short |
De Novo Mutation in the SCN5A Gene Associated with Brugada Syndrome |
title_full |
De Novo Mutation in the SCN5A Gene Associated with Brugada Syndrome |
title_fullStr |
De Novo Mutation in the SCN5A Gene Associated with Brugada Syndrome |
title_full_unstemmed |
De Novo Mutation in the SCN5A Gene Associated with Brugada Syndrome |
title_sort |
de novo mutation in the scn5a gene associated with brugada syndrome |
publisher |
Cell Physiol Biochem Press GmbH & Co KG |
series |
Cellular Physiology and Biochemistry |
issn |
1015-8987 1421-9778 |
publishDate |
2015-07-01 |
description |
Background: Brugada syndrome (BrS) is a genetically determined cardiac electrical disorder, characterized by typical electrocardiography (ECG) alterations, and it is an arrhythmogenic syndrome that may lead to sudden cardiac death. The most common genotype found among BrS patients is caused by mutations in the SCN5A gene, which lead to a loss of function of the cardiac sodium (Na+) channel (Nav1.5) by different mechanisms. Methods: The assay of confocal laser microscopy and western blot were used to identify the expression and location of L812Q at the cell surface. Characterization of Nav1.5 L812Q mutant Na+ channels was text by patch-clamp recordings, and the PHYRE2 server was used to build a model for human Nav1.5 channel. Results: Here, we report that a novel missense SCN5A mutation, L812Q, localized in the DII-S4 transmembrane region of the Nav1.5 channel protein, was identified in an index patient who showed a typical BrS type-1 ECG phenotype. The mutation was absent in the patient's parents and brother. Heterologous expression of the wild-type (WT) and L812Q mutant Nav1.5 channels in human embryonic kidney cells (HEK293 cells) reveals that the mutation results in a reduction of Na+ current density as well as ∼20 mV hyperpolarizing shift of the voltage dependence of inactivation. The voltage dependence of activation and the time course for recovery from inactivation are not affected by the mutation. The hyperpolarizing shift of the voltage dependence of inactivation caused a reduction of the Na+ window current as well. In addition, western blot and confocal laser microscopy imaging experiments showed that the mutation causes fewer channel to be expressed at the membrane than WT channel. A large proportion of the mutant channels are retained in the cytoplasm, probably in the endoplasmic reticulum. Conclusion: The decrease of channel expression, hyperpolarizing shift of voltage dependence of inactivation, and a decline of Na+ window current caused by L812Q mutation lead to a reduction of Na+ current during the upstroke and the repolarization phases of cardiac action potential, which contribute to the development of BrS. |
topic |
SCN5A Sodium Channel Gating Brugada Syndrome Arrhythmia Cardiac depolarization Ion channel trafficking |
url |
http://www.karger.com/Article/FullText/430189 |
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