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Nagata Y, Watanabe R, Eichhorn C, Ohno S, Aiba T, Ishikawa T, Nakano Y, Aizawa Y, Hayashi K, Murakoshi N, Nakajima T, Yagihara N, Mishima H, Sudo T, Higuchi C, Takahashi A, Sekine A, Makiyama T, Tanaka Y, Watanabe A, Tachibana M, Morita H, Yoshiura KI, Tsunoda T, Watanabe H, Kurabayashi M, Nogami A, Kihara Y, Horie M, Shimizu W, Makita N, Tanaka T. Targeted deep sequencing analyses of long QT syndrome in a Japanese population. PLoS One 2022; 17:e0277242. [PMID: 36480497 PMCID: PMC9731492 DOI: 10.1371/journal.pone.0277242] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2022] [Accepted: 10/22/2022] [Indexed: 12/13/2022] Open
Abstract
Long QT syndrome (LQTS) is one of the most common inherited arrhythmias and multiple genes have been reported as causative. Presently, genetic diagnosis for LQTS patients is becoming widespread and contributing to implementation of therapies. However, causative genetic mutations cannot be detected in about 20% of patients. To elucidate additional genetic mutations in LQTS, we performed deep-sequencing of previously reported 15 causative and 85 candidate genes for this disorder in 556 Japanese LQTS patients. We performed in-silico filtering of the sequencing data and found 48 novel variants in 33 genes of 53 cases. These variants were predicted to be damaging to coding proteins or to alter the binding affinity of several transcription factors. Notably, we found that most of the LQTS-related variants in the RYR2 gene were in the large cytoplasmic domain of the N-terminus side. They might be useful for screening of LQTS patients who had no known genetic factors. In addition, when the mechanisms of these variants in the development of LQTS are revealed, it will be useful for early diagnosis, risk stratification, and selection of treatment.
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Affiliation(s)
- Yuki Nagata
- Bioresourse Research Center, Tokyo Medical and Dental University (TMDU), Tokyo, Japan
- Department of Human Genetics and Disease Diversity, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), Tokyo, Japan
| | - Ryo Watanabe
- Department of Human Genetics and Disease Diversity, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), Tokyo, Japan
| | - Christian Eichhorn
- Department of Human Genetics and Disease Diversity, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), Tokyo, Japan
- Private University of the Principality of Liechtenstein, Triesen, Liechtenstein
| | - Seiko Ohno
- Department of Bioscience and Genetics, National Cerebral and Cardiovascular Center, Suita, Japan
| | - Takeshi Aiba
- Devision of Arrhythmia, National Cerebral and Cardiovascular Center, Suita, Japan
| | - Taisuke Ishikawa
- Omics Research Center, National Cerebral and Cardiovascular Center, Suita, Japan
| | - Yukiko Nakano
- Department of Cardiovascular Medicine, Hiroshima University, Hiroshima, Japan
| | - Yoshiyasu Aizawa
- Department of Cardiology, International University of Health and Welfare Narita Hospital, Narita, Japan
| | - Kenshi Hayashi
- Department of Cardiovascular Medicine, Kanazawa University Graduate School of Medical Sciences, Kanazawa, Japan
| | - Nobuyuki Murakoshi
- Department of Cardiology, Faculty of Medicine, University of Tsukuba, Tsukuba, Japan
| | - Tadashi Nakajima
- Department of Cardiovascular Medicine, Gunma University Graduate School of Medicine, Maebashi, Japan
| | - Nobue Yagihara
- Department of Cardiovascular Medicine, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - Hiroyuki Mishima
- Department of Human Genetics, Atomic Bomb Disease Institute, Nagasaki University, Nagasaki, Japan
| | - Takeaki Sudo
- Institute of Education, Tokyo Medical and Dental University (TMDU), Tokyo, Japan
| | - Chihiro Higuchi
- Artificial Intelligence Center for Health and Biomedical Research, National Institutes of Biomedical Innovation, Health and Nutrition, Ibaraki, Japan
| | - Atsushi Takahashi
- Department of Genomic Medicine, National Cerebral and Cardiovascular Center, Suita, Japan
| | - Akihiro Sekine
- Department of Infection and Host Defense, Graduate School of Medicine, Chiba University, Chiba, Japan
| | - Takeru Makiyama
- Department of Cardiovascular Medicine, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Yoshihiro Tanaka
- Center for Arrhythmia Research, Northwestern University Feinberg School of Medicine, Chicago, Illinois, United States of America
| | - Atsuyuki Watanabe
- Department of Cardiology, National Hospital Organization Okayama Medical Center, Okayama, Japan
| | - Motomi Tachibana
- Department of Cardiology, Sakakibara heart institute of Okayama, Okayama, Japan
| | - Hiroshi Morita
- Department of Cardiovascular Therapeutics, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan
| | - Koh-ichiro Yoshiura
- Department of Human Genetics, Atomic Bomb Disease Institute, Nagasaki University, Nagasaki, Japan
- Division of Advanced Preventive Medical Sciences and Leading Medical Research Core Unit, Nagasaki Univerisity Graduate School of Biomedical Sciences, Nagasaki, Japan
| | - Tatsuhiko Tsunoda
- Laboratory for Medical Science Mathematics, Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
- Laboratory for Medical Science Mathematics, RIKEN Center for Integrative Medical Sciences, Yokohama, Japan
| | - Hiroshi Watanabe
- Department of Cardiovascular Medicine, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - Masahiko Kurabayashi
- Department of Cardiovascular Medicine, Gunma University Graduate School of Medicine, Maebashi, Japan
| | - Akihiko Nogami
- Department of Cardiology, Faculty of Medicine, University of Tsukuba, Tsukuba, Japan
| | - Yasuki Kihara
- Department of Cardiovascular Medicine, Hiroshima University, Hiroshima, Japan
| | - Minoru Horie
- Department of Cardiovascular Medicine, Shiga University of Medical Science, Otsu, Japan
| | - Wataru Shimizu
- Department of Cardiovascular Medicine, Nippon Medical School, Tokyo, Japan
| | - Naomasa Makita
- Omics Research Center, National Cerebral and Cardiovascular Center, Suita, Japan
| | - Toshihiro Tanaka
- Bioresourse Research Center, Tokyo Medical and Dental University (TMDU), Tokyo, Japan
- Department of Human Genetics and Disease Diversity, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (TMDU), Tokyo, Japan
- * E-mail:
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Mahdieh N, Khorgami M, Soveizi M, Seyed Aliakbar S, Dalili M, Rabbani B. Genetic homozygosity in a diverse population: An experience of long QT syndrome. Int J Cardiol 2020; 316:117-124. [PMID: 32470535 DOI: 10.1016/j.ijcard.2020.05.056] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Revised: 05/02/2020] [Accepted: 05/18/2020] [Indexed: 11/20/2022]
Abstract
BACKGROUND Genomic variations have shown an ethnic-specific pattern within various cohorts. Genetic variants of KCNQ1, KCNH2, SCN5A and KCNE1 causing LQT syndrome have been described in many populations. In this article the spectrum of variants of these genes is presented in Iranian patients. METHODS 102 unrelated individuals diagnosed with LQT were enrolled in this study. Clinical and electrocardiogram (ECG) data of 95 patients were documented, and analyzed by expert pediatric cardiologists. Coding regions and exon-intron boundaries were amplified and sequenced. Segregation analysis was done for novel variants as well as in silico analyses. RESULTS Sixty nine of 95 cases (73%) had Schwartz score of ≥3.5. The causal variants were found in 31 cases (9 novel variants). 21 patients had KCNQ1 (LQTS1) of which15 patients were homozygous for KCNQ1 variants, 9 of these patients (29%) had a Jervell and Lange-Nielsen phenotype. 4 patients had KCNH2 (LQTS2) variants, 7 cases had SCN5A had heterozygous variants, and 2 cases had heterozygous variants in KCNE1 (LQTS5). 19 variants were missense, 3 were nonsense, and 3 were frameshifts. There was one large deletion and 3 intronic variants. CONCLUSION The yield of genetic testing and the genotype profile of LQTS patients in Iran is different from reports elsewhere, with lower overall yield and with 48% having homozygous states.
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Affiliation(s)
- Nejat Mahdieh
- Rajaie Cardiovascular Medical and Research Center, Iran University of Medical Sciences, Tehran, Iran; Growth and development research center, Tehran University of Medical Sciences, Tehran, Iran
| | - Mohammadrafi Khorgami
- Rajaie Cardiovascular Medical and Research Center, Iran University of Medical Sciences, Tehran, Iran
| | - Mahdieh Soveizi
- Rajaie Cardiovascular Medical and Research Center, Iran University of Medical Sciences, Tehran, Iran
| | - Saranaz Seyed Aliakbar
- Rajaie Cardiovascular Medical and Research Center, Iran University of Medical Sciences, Tehran, Iran
| | - Mohammad Dalili
- Rajaie Cardiovascular Medical and Research Center, Iran University of Medical Sciences, Tehran, Iran.
| | - Bahareh Rabbani
- Rajaie Cardiovascular Medical and Research Center, Iran University of Medical Sciences, Tehran, Iran; Growth and development research center, Tehran University of Medical Sciences, Tehran, Iran.
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Abstract
Kv7 channels (Kv7.1-7.5) are voltage-gated K+ channels that can be modulated by five β-subunits (KCNE1-5). Kv7.1-KCNE1 channels produce the slow-delayed rectifying K+ current, IKs, which is important during the repolarization phase of the cardiac action potential. Kv7.2-7.5 are predominantly neuronally expressed and constitute the muscarinic M-current and control the resting membrane potential in neurons. Kv7.1 produces drastically different currents as a result of modulation by KCNE subunits. This flexibility allows the Kv7.1 channel to have many roles depending on location and assembly partners. The pharmacological sensitivity of Kv7.1 channels differs from that of Kv7.2-7.5 and is largely dependent upon the number of β-subunits present in the channel complex. As a result, the development of pharmaceuticals targeting Kv7.1 is problematic. This review discusses the roles and the mechanisms by which different signaling pathways affect Kv7.1 and KCNE channels and could potentially provide different ways of targeting the channel.
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Affiliation(s)
- Emely Thompson
- Department of Anesthesiology, Pharmacology, and Therapeutics, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada;
| | - Jodene Eldstrom
- Department of Anesthesiology, Pharmacology, and Therapeutics, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada;
| | - David Fedida
- Department of Anesthesiology, Pharmacology, and Therapeutics, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada;
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Chen J, Weber M, Um SY, Walsh CA, Tang Y, McDonald TV. A dual mechanism for I(Ks) current reduction by the pathogenic mutation KCNQ1-S277L. PACING AND CLINICAL ELECTROPHYSIOLOGY: PACE 2011; 34:1652-64. [PMID: 21895724 DOI: 10.1111/j.1540-8159.2011.03190.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
BACKGROUND The hereditary long QT syndrome is characterized by prolonged ventricular repolarization that can be caused by mutations to the KCNQ1 gene, which encodes the α subunits of the cardiac potassium channel complex that carries the I(Ks) current (the β subunits are encoded by KCNE1). In this study, we characterized a deleterious variant, KCNQ1-S277L, found in a patient who presented with sudden cardiac death in the presence of cocaine use. METHODS The KCNQ1-S277L mutation was analyzed via whole-cell patch clamp, confocal imaging, surface biotinylation assays, and computer modeling. RESULTS Homomeric mutant KCNQ1-S277L channels were unable to carry current, either alone or with KCNE1. When co-expressed in a 50/50 ratio with WT KCNQ1, current density was reduced in a dominant-negative manner, with the residual current predominantly wild type. There was no change in the activation rate and minimal changes to voltage-dependent activation for both KCNQ1 current and I(Ks) current. Immunofluorescence confocal imaging revealed reduced surface expression of mutant KCNQ1-S277L, which was biochemically confirmed by surface biotinylation showing a 44% decrease in mutant surface expression. Expression of KCNQ1-S277L with human ether-a-go-go-related gene (HERG) did not significantly affect HERG protein or current density compared to KCNQ1-WT co-expression. CONCLUSION The KCNQ1-S277L mutation causes biophysical defects that result in dominant-negative reduction in KCNQ1 and I(Ks) current density, and a trafficking defect that results in reduced surface expression, both without affecting HERG/I(Kr) . KCNQ1-S277L mutation in the proband resulted in defective channels that compromised repolarization reserve, thereby enhancing the arrhythmic susceptibility to pharmacological blockage of I(Kr) current.
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Affiliation(s)
- Jerri Chen
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, New York, USA
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Jons C, O-Uchi J, Moss AJ, Reumann M, Rice JJ, Goldenberg I, Zareba W, Wilde AAM, Shimizu W, Kanters JK, McNitt S, Hofman N, Robinson JL, Lopes CMB. Use of mutant-specific ion channel characteristics for risk stratification of long QT syndrome patients. Sci Transl Med 2011; 3:76ra28. [PMID: 21451124 DOI: 10.1126/scitranslmed.3001551] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Inherited long QT syndrome (LQTS) is caused by mutations in ion channels that delay cardiac repolarization, increasing the risk of sudden death from ventricular arrhythmias. Currently, the risk of sudden death in individuals with LQTS is estimated from clinical parameters such as age, gender, and the QT interval, measured from the electrocardiogram. Even though a number of different mutations can cause LQTS, mutation-specific information is rarely used clinically. LQTS type 1 (LQT1), one of the most common forms of LQTS, is caused by mutations in the slow potassium current (I(Ks)) channel α subunit KCNQ1. We investigated whether mutation-specific changes in I(Ks) function can predict cardiac risk in LQT1. By correlating the clinical phenotype of 387 LQT1 patients with the cellular electrophysiological characteristics caused by an array of mutations in KCNQ1, we found that channels with a decreased rate of current activation are associated with increased risk of cardiac events (hazard ratio=2.02), independent of the clinical parameters usually used for risk stratification. In patients with moderate QT prolongation (a QT interval less than 500 ms), slower activation was an independent predictor for cardiac events (syncope, aborted cardiac arrest, and sudden death) (hazard ratio = 2.10), whereas the length of the QT interval itself was not. Our results indicate that genotype and biophysical phenotype analysis may be useful for risk stratification of LQT1 patients and suggest that slow channel activation is associated with an increased risk of cardiac events.
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Affiliation(s)
- Christian Jons
- Cardiology Division, Department of Medicine, University of Rochester School of Medicine and Dentistry, Rochester, NY 14642, USA
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Liu JF, Goldenberg I, Moss AJ, Shimizu W, Wilde AA, Hofman N, McNitt S, Zareba W, Miyamato Y, Robinson JL, Andrews ML. Phenotypic variability in Caucasian and Japanese patients with matched LQT1 mutations. Ann Noninvasive Electrocardiol 2008; 13:234-41. [PMID: 18713323 DOI: 10.1111/j.1542-474x.2008.00226.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
BACKGROUND Ethnic differences may affect the phenotypic expression of genetic disorders. However, data regarding the effect of ethnicity on outcome in patients with genetic cardiac disorders are limited. We compared the clinical course of Caucasian and Japanese long QT type-1 (LQT1) patients who were matched for mutations in the KCNQ1 gene. METHODS The study population comprised 62 Caucasian and 38 Japanese LQT1 patients from the International LQTS Registry who were identified as having six identical KCNQ1 mutations. The biophysical function of the mutations was categorized into dominant-negative (> 50%) or haploinsufficiency (< or =50%) reduction in cardiac repolarizing IKs potassium channel current. The primary end point of the study was the occurrence of a first cardiac event from birth through age 40 years. RESULTS Japanese patients had a significantly higher cumulative rate of cardiac events (67%) than Caucasian patients (39%; P = 0.01). The respective frequencies of dominant negative mutations in the two ethnic groups were 63% and 28% (P < 0.001). In multivariate analysis, Japanese patients had an 81% increase in the risk of cardiac events (P = 0.06) as compared with Caucasians. However, when the biophysical function of the mutations was included in the multivariate model, the risk associated with Japanese ethnicity was no longer evident (HR = 1.05; P = 0.89). Harboring a dominant negative mutation was shown to be the most powerful and significant predictor of outcome (HR = 3.78; P < 0.001). CONCLUSIONS Our data indicate that ethnic differences in the clinical expression of LQTS can be attributed to the differences in frequencies of the specific mutations within the two populations.
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Affiliation(s)
- Judy F Liu
- Cardiology Division of the Department of Medicine, University of Rochester School of Medicine and Dentistry, Rochester, NY14642, USA
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