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Kashiwa A, Itoh H, Makiyama T, Wada Y, Ozawa J, Kato K, Fukuyama M, Nakajima T, Ohno S, Horie M. Clinical characterization of type 1 long QT syndrome caused by C-terminus Kv7.1 variants. Heart Rhythm 2024:S1547-5271(24)00192-9. [PMID: 38367891 DOI: 10.1016/j.hrthm.2024.02.021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/31/2023] [Revised: 01/27/2024] [Accepted: 02/07/2024] [Indexed: 02/19/2024]
Abstract
BACKGROUND Variants in the KCNQ1 gene, encoding the α-subunit of the slow component of delayed rectifier K+ channel Kv7.1, cause long QT syndrome (LQTS) type 1. The location of variants may be one of the factors in determining prognosis. However, detailed genotype-phenotype relationships associated with C-terminus variants remain unelucidated. OBJECTIVE We investigated the clinical characteristics and variant-specific arrhythmic risks in patients with LQTS carrying Kv7.1 C-terminus variants. METHODS The study comprises 202 consecutive patients with LQTS (98 probands and 104 family members) who carry a rare heterozygous variant in the Kv7.1 C-terminus. Their clinical characteristics and arrhythmic events were investigated. RESULTS We identified 36 unique C-terminus variants (25 missense and 11 non-missense). The p.R366W variant was identified in 8 families, and p.T587M was identified in 21 families in large numbers from northwestern Japan. As for the location of the variant, we found that the variants in highly conserved regions and nonhelical domains were associated with longer QTc intervals compared with the variants in other regions. Both p.R366W and p.T587M variants are located in the highly conserved and functionally pivotal regions close to helices A and D, which are associated with calmodulin binding and channel assembly (tetramerization), respectively. The probands carrying p.T587M and p.R366W variants had worse arrhythmia outcomes compared with those with other C-terminus variants. The haplotype analysis of p.T587M families was suggestive of a founder effect. CONCLUSION The arrhythmic risk of C-terminus variants in Kv7.1 in LQTS is not homogeneous, and locations of variants can be a determining factor for prognosis.
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Affiliation(s)
- Asami Kashiwa
- Department of Cardiovascular Medicine, Kyoto University Graduate School of Medicine, Kyoto, Japan; Department of Cardiology, Niigata City General Hospital, Niigata, Japan.
| | - Hideki Itoh
- Division of Patient Safety, Hiroshima University Hospital, Minami-ku, Hiroshima, Japan
| | - Takeru Makiyama
- Department of Cardiovascular Medicine, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Yuko Wada
- Vanderbilt Center for Arrhythmia Research and Therapeutics, Division of Clinical Pharmacology, Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Junichi Ozawa
- Department of Pediatrics, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - Koichi Kato
- Department of Cardiovascular Medicine, Shiga University of Medical Science, Shiga, Japan
| | - Megumi Fukuyama
- Department of Cardiovascular Medicine, Shiga University of Medical Science, Shiga, Japan
| | - Tadashi Nakajima
- Department of Cardiovascular Medicine, Gunma University Graduate School of Medicine, Maebashi, Japan
| | - Seiko Ohno
- Department of Bioscience and Genetics, National Cerebral and Cardiovascular Center, Osaka, Japan
| | - Minoru Horie
- Department of Cardiovascular Medicine, Shiga University of Medical Science, Shiga, Japan
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Bora E, Bulut AY, Cankaya T, Cinleti T, Genç HZ, Ozcan EE, Ozpelit E, Ulgenalp A, Caglayan AO. Clinical Heterogeneity in Patients with Long QT Syndrome and Segregation of Single Nucleotide Variants and Clinical Symptoms in 17 Affected Families. Mol Syndromol 2023; 14:363-374. [PMID: 37901857 PMCID: PMC10601819 DOI: 10.1159/000530513] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2022] [Accepted: 03/28/2023] [Indexed: 10/31/2023] Open
Abstract
Introduction Long QT syndrome (LQTS) is a disorder of ventricular myocardial repolarization characterized by a prolonged QT interval on the electrocardiogram. It increases the risk of ventricular arrhythmias, which can cause syncope or sudden cardiac death. In this study, we study the genotype-phenotype relationships of patients referred to us with suspected arrhythmia syndrome. Methods Seventeen cases and their twenty relatives were evaluated. Next-generation sequencing analysis was performed for 17 LQTS-related genes. Results We detected seventeen single nucleotide variants (SNVs) with potential pathogenic significance in 26 of the 36 subjects analyzed. KCNH2 c.172G>A, KCNQ1 c.1768G>A, ANK2 c.4666A>T, c.1484_1485delCT, KCNH2 c.1888G>A were reported as pathogenic or likely pathogenic in HGMD variant classification database. Conclusion Current study pointed out that early diagnosis can be life-saving for patients and their families by taking family history and detailed examination. Also, we highlight the clinical heterogeneity of arrhythmia syndrome through a patient with a dual phenotype.
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Affiliation(s)
- Elcin Bora
- Department of Medical Genetics, Dokuz Eylul University Faculty of Medicine, Izmir, Turkey
| | - Ayca Yıldız Bulut
- Department of Medical Genetics, Dokuz Eylul University Faculty of Medicine, Izmir, Turkey
| | - Tufan Cankaya
- Department of Medical Genetics, Dokuz Eylul University Faculty of Medicine, Izmir, Turkey
| | - Tayfun Cinleti
- Division of Medical Genetics, Department of Pediatrics, Dokuz Eylul University Faculty of Medicine, Izmir, Turkey
| | - Halise Zeynep Genç
- Division of Cardiology, Department of Pediatrics, Dokuz Eylul University Faculty of Medicine, Izmir, Turkey
| | - Emin Evren Ozcan
- Department of Cardiology, Dokuz Eylul University Faculty of Medicine, Izmir, Turkey
| | - Ebru Ozpelit
- Department of Cardiology, Dokuz Eylul University Faculty of Medicine, Izmir, Turkey
| | - Ayfer Ulgenalp
- Department of Medical Genetics, Dokuz Eylul University Faculty of Medicine, Izmir, Turkey
| | - Ahmet Okay Caglayan
- Department of Medical Genetics, Dokuz Eylul University Faculty of Medicine, Izmir, Turkey
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3
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Kelleher ST, Prendiville T, Carroll A. Long QT syndrome presenting as fetal bradycardia and 2:1 atrioventricular block in a preterm infant. Arch Dis Child Fetal Neonatal Ed 2023; 108:545. [PMID: 35172986 DOI: 10.1136/archdischild-2021-323281] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Accepted: 02/01/2022] [Indexed: 11/04/2022]
Affiliation(s)
- Sean T Kelleher
- Department of Neonatology, University Hospital Waterford, Waterford, Waterford, Ireland
| | - Terence Prendiville
- Department of Paediatric Cardiology, Children's Health Ireland at Crumlin, Crumlin, Dublin, Ireland
| | - Aoife Carroll
- Department of Neonatology, University Hospital Waterford, Waterford, Waterford, Ireland
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4
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Westphal DS, Hauser M, Beckmann BM, Wolf CM, Hessling G, Oberhoffer-Fritz R, Wacker-Gussmann A. Fetal Bradycardia Caused by Monogenic Disorders-A Review of the Literature. J Clin Med 2022; 11:jcm11236880. [PMID: 36498454 PMCID: PMC9741304 DOI: 10.3390/jcm11236880] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2022] [Revised: 11/03/2022] [Accepted: 11/18/2022] [Indexed: 11/24/2022] Open
Abstract
Introduction: The standard obstetric definition of fetal bradycardia is a sustained fetal heart rate < 110 bpm over at least 10 min. Fetal bradycardia can be the first and only prenatal presentation of a heart disease. We present an overview on different genetic disorders that should be taken into consideration in case of diagnosed fetal bradycardia. Methods: A literature review was conducted using a PubMed- and OMIM-based search for monogenetic disorders causing fetal bradycardia in September 2022. Results: The review on the literature identified nine monogenic diseases that could lead to fetal bradycardia. Four of these disorders can be associated with extracardiac findings. Discussion: Genetic testing should be considered in cases with fetal bradycardia, especially in cases of additional extracardiac findings. Broad sequencing techniques and improved prenatal phenotyping could help to establish a diagnosis in an increasing number of cases.
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Affiliation(s)
- Dominik S. Westphal
- Department of Internal Medicine I, Klinikum Rechts der Isar, School of Medicine and Health, Technical University Munich, 81675 Munich, Germany
- Institute of Human Genetics, Klinikum Rechts der Isar, School of Medicine and Health, Technical University Munich, 81675 Munich, Germany
- Correspondence:
| | | | - Britt-Maria Beckmann
- Institute of Legal Medicine, University Hospital Frankfurt, Goethe University, 60596 Frankfurt, Germany
| | - Cordula M. Wolf
- DZHK (German Centre for Cardiovascular Research), Partner Site Munich Heart Alliance, 80802 Munich, Germany
- Department of Congenital Heart Defects and Pediatric Cardiology, German Heart Center Munich, School of Medicine and Health, Technical University Munich, 80636 Munich, Germany
| | - Gabriele Hessling
- Department of Congenital Heart Defects and Pediatric Cardiology, German Heart Center Munich, School of Medicine and Health, Technical University Munich, 80636 Munich, Germany
| | - Renate Oberhoffer-Fritz
- Department of Congenital Heart Defects and Pediatric Cardiology, German Heart Center Munich, School of Medicine and Health, Technical University Munich, 80636 Munich, Germany
- Institute of Preventive Pediatrics, TUM Department of Sport and Health Sciences, Technical University Munich, 80992 Munich, Germany
| | - Annette Wacker-Gussmann
- Department of Congenital Heart Defects and Pediatric Cardiology, German Heart Center Munich, School of Medicine and Health, Technical University Munich, 80636 Munich, Germany
- Institute of Preventive Pediatrics, TUM Department of Sport and Health Sciences, Technical University Munich, 80992 Munich, Germany
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5
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Ataíde Silva R, R Sousa A, de Carvalho MSL, Anjos R. Congenital long QT syndrome presenting as unexplained bradycardia. BMJ Case Rep 2022; 15:e242362. [PMID: 35236671 PMCID: PMC8895896 DOI: 10.1136/bcr-2021-242362] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/08/2022] [Indexed: 11/03/2022] Open
Abstract
Congenital long QT syndrome (LQTS) is a genetically autosomal heterogeneous disorder of the ion channels and causes about 10% of sudden death infant syndrome in newborns. Its estimated prevalence is approximately 1 in 2500, probably underestimated because of its clinical heterogenicity. Few cases of neonatal LQTS have been reported. In 4% of them, life-threatening arrhythmic events can be the first manifestation of LQTS. The authors report two cases of neonatal LQTS with heterogeneous genetic mutations. Both manifested by bradycardia, one since fetal life. One case had serious arrhythmias during beta blocker therapeutic establishment needing a pacemaker implantation. Genetic mutations found were not the most frequently described in association with neonatal bradycardia, thus the importance of this report. Presentation with bradycardia is relatively frequent in neonatal period, thus LQTS should be actively investigated in neonates with unexplained bradycardia. Beta blocker therapy reduces QTc and avoids arrhythmic events and sudden death.
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Affiliation(s)
- Rita Ataíde Silva
- Department of Pediatric Cardiology, Centro Hospitalar de Lisboa Ocidental EPE, Lisboa, Carnaxide, Portugal
| | - Ana R Sousa
- Department of Pediatric Cardiology, Centro Hospitalar de Lisboa Ocidental EPE, Lisboa, Carnaxide, Portugal
| | | | - Rui Anjos
- Department of Pediatric Cardiology, Centro Hospitalar de Lisboa Ocidental EPE, Lisboa, Carnaxide, Portugal
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6
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Approach to inherited arrhythmias in pregnancy. INTERNATIONAL JOURNAL OF CARDIOLOGY CONGENITAL HEART DISEASE 2021. [DOI: 10.1016/j.ijcchd.2021.100264] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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7
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Oral contraceptives and their effect on arrhythmogenesis in long QT syndrome: Does it matter? Heart Rhythm 2021; 19:49-50. [PMID: 34389502 DOI: 10.1016/j.hrthm.2021.08.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Accepted: 08/06/2021] [Indexed: 11/21/2022]
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8
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Pærregaard MM, Hvidemose SO, Pihl C, Sillesen AS, Parvin SB, Pietersen A, Iversen KK, Bundgaard H, Christensen AH. Defining the normal QT interval in newborns: the natural history and reference values for the first 4 weeks of life. Europace 2021; 23:278-286. [PMID: 32940668 DOI: 10.1093/europace/euaa143] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Revised: 03/28/2020] [Accepted: 05/11/2020] [Indexed: 01/09/2023] Open
Abstract
AIMS Evaluation of the neonatal QT interval is important to diagnose arrhythmia syndromes and evaluate side effects of drugs. We aimed at describing the natural history of the QT interval duration during the first 4 weeks of life and to provide reference values from a large general population sample. METHODS AND RESULTS The Copenhagen Baby Heart Study is a prospective general population study that offered cardiac evaluation of newborns. Eight-lead electrocardiograms were obtained and analysed with a computerized algorithm with manual validation. We included 14 164 newborns (52% boys), aged 0-28 days, with normal echocardiograms. The median values (ms, 2-98%ile) for the corrected intervals QTc (Bazett), QTc (Hodges), QTc (Fridericia), and QTc (Framingham) were 419 (373-474), 419 (373-472), 364 (320-414), and 363 (327-405). During the 4 weeks, we observed a small decrease of QTcFramingham, and an increase of QTcHodges (both P < 0.01), while QTcBazett and QTcFridericia did not change (P > 0.05). Applying published QT interval cut-off values resulted in 5-25% of the newborns having QT prolongation. Uncorrected QT intervals decreased linearly with increasing heart rate (HR). Sex and infant size did not affect the QT interval and the gestational age (GA) only showed an effect when comparing the extreme low- vs. high GA groups (≤34 vs. ≥42 weeks, P = 0.021). CONCLUSION During the 4 weeks QTcFramingham and QTcHodges showed minor changes, whereas QTcBazett and QTcFridericia were stable. The QT interval was unaffected by sex and infant size and GA only showed an effect in very premature newborns. Reference values for HR-specific uncorrected QT intervals may facilitate a more accurate diagnosis of newborns with abnormal QT intervals.
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Affiliation(s)
- Maria Munk Pærregaard
- Department of Cardiology, Herlev-Gentofte Hospital, Copenhagen University Hospital, Borgmester Ib Juuls Vej 1, DK-2730 Herlev, Copenhagen, Denmark
| | - Sara Osted Hvidemose
- Department of Cardiology, Herlev-Gentofte Hospital, Copenhagen University Hospital, Borgmester Ib Juuls Vej 1, DK-2730 Herlev, Copenhagen, Denmark
| | - Christian Pihl
- Department of Cardiology, Herlev-Gentofte Hospital, Copenhagen University Hospital, Borgmester Ib Juuls Vej 1, DK-2730 Herlev, Copenhagen, Denmark
| | - Anne-Sophie Sillesen
- Department of Cardiology, Herlev-Gentofte Hospital, Copenhagen University Hospital, Borgmester Ib Juuls Vej 1, DK-2730 Herlev, Copenhagen, Denmark
| | - Solmaz Bagheri Parvin
- Department of Cardiology, Herlev-Gentofte Hospital, Copenhagen University Hospital, Borgmester Ib Juuls Vej 1, DK-2730 Herlev, Copenhagen, Denmark
| | - Adrian Pietersen
- Department of Cardiology, Herlev-Gentofte Hospital, Copenhagen University Hospital, Borgmester Ib Juuls Vej 1, DK-2730 Herlev, Copenhagen, Denmark
| | - Kasper Karmark Iversen
- Department of Cardiology, Herlev-Gentofte Hospital, Copenhagen University Hospital, Borgmester Ib Juuls Vej 1, DK-2730 Herlev, Copenhagen, Denmark
| | - Henning Bundgaard
- Department of Cardiology, The Capital Regions Unit for Inherited Cardiac Diseases, The Heart Center, Rigshospitalet, Copenhagen University Hospital, Inge Lehmanns Vej 7, DK-2100 Copenhagen, Denmark
| | - Alex Hørby Christensen
- Department of Cardiology, Herlev-Gentofte Hospital, Copenhagen University Hospital, Borgmester Ib Juuls Vej 1, DK-2730 Herlev, Copenhagen, Denmark.,Department of Cardiology, The Capital Regions Unit for Inherited Cardiac Diseases, The Heart Center, Rigshospitalet, Copenhagen University Hospital, Inge Lehmanns Vej 7, DK-2100 Copenhagen, Denmark
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9
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Sawyer BL, Tristani-Firouzi M, Wells LE, Vatta M, Etheridge SP. Maternal mosaicism in long QT syndrome due to a pathogenic variant in KCNH2. HeartRhythm Case Rep 2021; 7:74-78. [PMID: 33665105 PMCID: PMC7897747 DOI: 10.1016/j.hrcr.2020.11.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
- Briana L. Sawyer
- Division of Pediatric Cardiology, Department of Pediatrics, University of Utah, Salt Lake City, Utah
| | - Martin Tristani-Firouzi
- Division of Pediatric Cardiology, Department of Pediatrics, University of Utah, Salt Lake City, Utah
| | - Layne E. Wells
- Department of Precision Genomics, Intermountain Primary Children’s Hospital, Salt Lake City, Utah
| | - Matteo Vatta
- Invitae Corporation, San Francisco, California
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, Indiana
| | - Susan P. Etheridge
- Division of Pediatric Cardiology, Department of Pediatrics, University of Utah, Salt Lake City, Utah
- Address reprint requests and correspondence: Dr Susan P. Etheridge, University of Utah Division of Pediatric Cardiology, Department of Pediatrics, 81 N. Mario Capecchi Dr, Salt Lake City, UT 84113.
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10
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Huang H, Chamness LM, Vanoye CG, Kuenze G, Meiler J, George AL, Schlebach JP, Sanders CR. Disease-linked supertrafficking of a potassium channel. J Biol Chem 2021; 296:100423. [PMID: 33600800 PMCID: PMC7988323 DOI: 10.1016/j.jbc.2021.100423] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Revised: 02/04/2021] [Accepted: 02/12/2021] [Indexed: 12/21/2022] Open
Abstract
Gain-of-function (GOF) mutations in the voltage-gated potassium channel subfamily Q member 1 (KCNQ1) can induce cardiac arrhythmia. In this study, it was tested whether any of the known human GOF disease mutations in KCNQ1 act by increasing the amount of KCNQ1 that reaches the cell surface-"supertrafficking." Seven of the 15 GOF mutants tested were seen to surface traffic more efficiently than the WT channel. Among these, we found that the levels of R231C KCNQ1 in the plasma membrane were fivefold higher than the WT channel. This was shown to arise from the combined effects of enhanced efficiency of translocon-mediated membrane integration of the S4 voltage-sensor helix and from enhanced post-translational folding/trafficking related to the energetic linkage of C231 with the V129 and F166 side chains. Whole-cell electrophysiology recordings confirmed that R231C KCNQ1 in complex with the voltage-gated potassium channel-regulatory subfamily E member 1 not only exhibited constitutive conductance but also revealed that the single-channel activity of this mutant is only 20% that of WT. The GOF phenotype associated with R231C therefore reflects the effects of supertrafficking and constitutive channel activation, which together offset reduced channel activity. These investigations show that membrane protein supertrafficking can contribute to human disease.
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Affiliation(s)
- Hui Huang
- Department of Biochemistry, Vanderbilt University, Nashville, Tennessee, USA; Center for Structural Biology, Vanderbilt University, Nashville, Tennessee, USA
| | - Laura M Chamness
- Department of Chemistry, Indiana University, Bloomington, Indiana, USA
| | - Carlos G Vanoye
- Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Georg Kuenze
- Departments of Chemistry and Pharmacology, Vanderbilt University, Nashville, Tennessee, USA; Department of Bioinformatics, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Jens Meiler
- Center for Structural Biology, Vanderbilt University, Nashville, Tennessee, USA; Departments of Chemistry and Pharmacology, Vanderbilt University, Nashville, Tennessee, USA; Department of Bioinformatics, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Alfred L George
- Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | | | - Charles R Sanders
- Department of Biochemistry, Vanderbilt University, Nashville, Tennessee, USA; Center for Structural Biology, Vanderbilt University, Nashville, Tennessee, USA; Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, USA.
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11
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Villafane J, Miller JR, Glickstein J, Johnson JN, Wagner J, Snyder CS, Filina T, Pomeroy SL, Sexson-Tejtel SK, Haxel C, Gottlieb J, Eghtesady P, Chowdhury D. Loss of Consciousness in the Young Child. Pediatr Cardiol 2021; 42:234-254. [PMID: 33388850 DOI: 10.1007/s00246-020-02498-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Accepted: 11/07/2020] [Indexed: 01/03/2023]
Abstract
In the very young child (less than eight years of age), transient loss of consciousness represents a diagnostic and management dilemma for clinicians. While most commonly benign, syncope may be due to cardiac dysfunction which can be life-threatening. It can be secondary to an underlying ion channelopathy, cardiac inflammation, cardiac ischemia, congenital heart disease, cardiomyopathy, or pulmonary hypertension. Patients with genetic disorders require careful evaluation for a cardiac cause of syncope. Among the noncardiac causes, vasovagal syncope is the most common etiology. Breath-holding spells are commonly seen in this age group. Other causes of transient loss of consciousness include seizures, neurovascular pathology, head trauma, psychogenic pseudosyncope, and factitious disorder imposed on another and other forms of child abuse. A detailed social, present, past medical, and family medical history is important when evaluating loss of consciousness in the very young. Concerning characteristics of syncope include lack of prodromal symptoms, no preceding postural changes or occurring in a supine position, after exertion or a loud noise. A family history of sudden unexplained death, ion channelopathy, cardiomyopathy, or congenital deafness merits further evaluation. Due to inherent challenges in diagnosis at this age, often there is a lower threshold for referral to a specialist.
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Affiliation(s)
- Juan Villafane
- Department of Pediatrics, University of Cincinnati and Cincinnati Children's Hospital, Cincinnati, OH, USA. .,Department of Pediatrics, 743 East Broadway, Suite 300, Louisville, KY, 40202, USA.
| | - Jacob R Miller
- Department of Surgery, Division of Cardiothoracic Surgery, St. Louis Children's Hospital, Washington University School of Medicine, St. Louis, MO, USA
| | - Julie Glickstein
- Department of Pediatrics, Columbia University Medical Center, New York-Presbyterian Hospital, New York, NY, USA
| | - Jonathan N Johnson
- Department of Pediatric and Adolescent Medicine, Division of Pediatric Cardiology, Mayo Clinic, Rochester, MN, USA
| | - Jonathan Wagner
- Department of Pediatrics, University of Missouri-Kansas City School of Medicine, Kansas City, MO, USA
| | - Chris S Snyder
- Congenital Heart Collaborative, Rainbow Babies and Children's Hospital, Case Western University, Cleveland, OH, USA
| | - Tatiana Filina
- Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Scott L Pomeroy
- Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | | | - Caitlin Haxel
- Department of Pediatrics, Children's Hospital of Colorado, University of Colorado School of Medicine, Aurora, CO, USA
| | | | - Pirooz Eghtesady
- Department of Surgery, Division of Cardiothoracic Surgery, St. Louis Children's Hospital, Washington University School of Medicine, St. Louis, MO, USA
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12
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Abstract
Congenital Long QT Syndrome (LQTS) is a dangerous arrhythmic disorder that can be diagnosed in children with bradycardia. It is characterised by a prolonged QT interval and torsades de pointes that may cause sudden death. Long QT syndrome is an ion channelopathy with complex molecular and physiological infrastructure. Unlike the acquired type, congenital LQTS has a genetic inheritance and it may be diagnosed by syncope, stress in activity, cardiac dysfunction, sudden death or sometimes incidentally. Permanent pacemaker implantation is required for LQTS with resistant bradycardia even in children to resolve symptoms and avoid sudden death.
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13
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Importance of Analysis of Arrhythmia Mechanism in Predicting Outcomes in Fetal Bradycardia: A Single-Centre Retrospective Study from a Dedicated Fetal Cardiology Unit in South India. JOURNAL OF FETAL MEDICINE 2020. [DOI: 10.1007/s40556-020-00264-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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14
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Moore JP, Gallotti RG, Shannon KM, Bos JM, Sadeghi E, Strasburger JF, Wakai RT, Horigome H, Clur SA, Hill AC, Shah MJ, Behere S, Sarquella-Brugada G, Czosek R, Etheridge SP, Fischbach P, Kannankeril PJ, Motonaga K, Landstrom AP, Williams M, Patel A, Dagradi F, Tan RB, Stephenson E, Krishna MR, Miyake CY, Lee ME, Sanatani S, Balaji S, Young ML, Siddiqui S, Schwartz PJ, Shivkumar K, Ackerman MJ. Genotype Predicts Outcomes in Fetuses and Neonates With Severe Congenital Long QT Syndrome. JACC Clin Electrophysiol 2020; 6:1561-1570. [PMID: 33213816 DOI: 10.1016/j.jacep.2020.06.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Revised: 05/26/2020] [Accepted: 06/02/2020] [Indexed: 11/16/2022]
Abstract
OBJECTIVES This study sought to determine the relationship between long QT syndrome (LQTS) subtype (LTQ1, LTQ2, LTQ3) and postnatal cardiac events (CEs). BACKGROUND LQTS presenting with 2:1 atrioventricular block or torsades de pointes in the fetus and/or neonate has been associated with risk for major CEs, but overall outcomes and predictors remain unknown. METHODS A retrospective study involving 25 international centers evaluated the course of fetuses/newborns diagnosed with congenital LQTS and either 2:1 atrioventricular block or torsades de pointes. The primary outcomes were age at first CE after dismissal from the newborn hospitalization and death and/or cardiac transplantation during follow-up. CE was defined as aborted cardiac arrest, appropriate shock from implantable cardioverter-defibrillator, or sudden cardiac death. RESULTS A total of 84 fetuses and/or neonates were identified with LQTS (12 as LQT1, 35 as LQT2, 37 as LQT3). Median gestational age at delivery was 37 weeks (interquartile range: 35 to 39 weeks) and age at hospital discharge was 3 weeks (interquartile range: 2 to 5 weeks). Fetal demise occurred in 2 and pre-discharge death in 1. Over a median of 5.2 years, there were 1 LQT1, 3 LQT2, and 23 LQT3 CEs (13 aborted cardiac arrests, 5 sudden cardiac deaths, and 9 appropriate shocks). One patient with LQT1 and 11 patients with LQT3 died or received cardiac transplant during follow-up. The only multivariate predictor of post-discharge CEs was LQT3 status (LQT3 vs. LQT2: hazard ratio: 8.4; 95% confidence interval: 2.6 to 38.9; p < 0.001), and LQT3, relative to LQT2, genotype predicted death and/or cardiac transplant (p < 0.001). CONCLUSIONS In this large multicenter study, fetuses and/or neonates with LQT3 but not those with LQT1 or LQT2 presenting with severe arrhythmias were at high risk of not only frequent, but lethal CEs.
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Affiliation(s)
- Jeremy P Moore
- Division of Pediatric Cardiology, University of California Los Angeles (UCLA) Medical Center, Los Angeles, California, USA; UCLA Cardiac Arrhythmia Center and Ahmanson Adult Congenital Heart Disease Center, UCLA Health System, Los Angeles, California, USA.
| | - Roberto G Gallotti
- Division of Pediatric Cardiology, University of California Los Angeles (UCLA) Medical Center, Los Angeles, California, USA; UCLA Cardiac Arrhythmia Center and Ahmanson Adult Congenital Heart Disease Center, UCLA Health System, Los Angeles, California, USA
| | - Kevin M Shannon
- Division of Pediatric Cardiology, University of California Los Angeles (UCLA) Medical Center, Los Angeles, California, USA; UCLA Cardiac Arrhythmia Center and Ahmanson Adult Congenital Heart Disease Center, UCLA Health System, Los Angeles, California, USA
| | - J Martijn Bos
- Department of Cardiovascular Medicine (Division of Heart Rhythm Services), Mayo Clinic, Rochester, Minnesota, USA; Division of Pediatric Cardiology, Department of Pediatric and Adolescent Medicine, Mayo Clinic, Rochester, Minnesota, USA; Department of Molecular Pharmacology and Experimental Therapeutics, Windland Smith Rice Sudden Death Genomics Laboratory, Mayo Clinic, Rochester, Minnesota, USA
| | - Elham Sadeghi
- Department of Pediatrics, Medical College of Wisconsin, Herma Heart Institute, Milwaukee, Wisconsin, USA
| | - Janette F Strasburger
- Department of Pediatrics, Medical College of Wisconsin, Herma Heart Institute, Milwaukee, Wisconsin, USA
| | - Ronald T Wakai
- Biomagnetism Laboratory, Department of Medical Physics, University of Wisconsin, Madison, Wisconsin, USA
| | | | - Sally-Ann Clur
- Department of Pediatric Cardiology, Emma Children's Hospital, Amsterdam University Medical Center, Amsterdam, the Netherlands
| | - Allison C Hill
- Division of Cardiology, Children's Hospital Los Angeles, Los Angeles, California, USA
| | - Maully J Shah
- Division of Cardiology, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - Shashank Behere
- Division of Cardiology, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - Georgia Sarquella-Brugada
- Arrhythmia, Inherited Cardiac Diseases Unit, Hospital Sant Joan de Déu, Barcelona, Spain; Medical Sciences Department, School of Medicine, University of Girona, Girona, Spain
| | - Richard Czosek
- The Heart Institute, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
| | - Susan P Etheridge
- Primary Children's Hospital, University of Utah School of Medicine, Salt Lake City, Utah, USA
| | - Peter Fischbach
- Division of Pediatric Cardiology, Children's Healthcare of Atlanta, Emory University, Atlanta, Georgia, USA
| | - Prince J Kannankeril
- Monroe Carrell Children's Hospital, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
| | - Kara Motonaga
- Division of Pediatric Cardiology, Stanford University, Palo Alto, California, USA
| | - Andrew P Landstrom
- Department of Pediatrics, Division of Cardiology, Duke University School of Medicine, Durham, North Carolina, USA; Department of Cell Biology, Duke University School of Medicine, Durham, North Carolina, USA
| | - Matthew Williams
- Division of Cardiology, Rady Children's Hospital, University of California San Diego, San Diego, California, USA
| | - Akash Patel
- Division of Pediatric Cardiology, University of California San Francisco Benioff Children's Hospital, University of California, San Francisco, California, USA
| | - Federica Dagradi
- Center for Cardiac Arrhythmias of Genetic Origin, Istituto di Ricovero e Cura a Carattere Scientifico, Istituto Auxologico Italiano, Milan, Italy
| | - Reina B Tan
- Division of Pediatric Cardiology, New York University Langone School of Medicine, New York, New York, USA
| | - Elizabeth Stephenson
- Labbatt Family Heart Centre, The Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada
| | | | - Christina Y Miyake
- Department of Pediatrics, Baylor College of Medicine, Houston, Texas, USA; Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, Texas, USA
| | - Michelle E Lee
- Department of Pediatrics, Baylor College of Medicine, Houston, Texas, USA; Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, Texas, USA
| | - Shubhayan Sanatani
- Division of Cardiology, British Columbia Children's Hospital, University of British Columbia, Vancouver, British Columbia, Canada
| | - Seshadri Balaji
- Division of Pediatric Cardiology, Oregon Health and Science University, Portland, Oregon, USA
| | - Ming-Lon Young
- Joe DiMaggio Children's Hospital Heart Institute, Memorial Healthcare System, Hollywood, Florida, USA
| | - Saad Siddiqui
- The Heart Institute for Children, Advocate Children's Hospital, Oak Lawn, Illinois, USA
| | - Peter J Schwartz
- Center for Cardiac Arrhythmias of Genetic Origin, Istituto di Ricovero e Cura a Carattere Scientifico, Istituto Auxologico Italiano, Milan, Italy; Department of Cardiology, Fondazione IRCCS Policlinico S. Matteo, Pavia, Italy; Molecular Cardiology Laboratory, Fondazione IRCCS Policlinico S. Matteo, Pavia, Italy
| | - Kalyanam Shivkumar
- Division of Pediatric Cardiology, University of California Los Angeles (UCLA) Medical Center, Los Angeles, California, USA; UCLA Cardiac Arrhythmia Center and Ahmanson Adult Congenital Heart Disease Center, UCLA Health System, Los Angeles, California, USA
| | - Michael J Ackerman
- Department of Cardiovascular Medicine (Division of Heart Rhythm Services), Mayo Clinic, Rochester, Minnesota, USA; Division of Pediatric Cardiology, Department of Pediatric and Adolescent Medicine, Mayo Clinic, Rochester, Minnesota, USA; Department of Molecular Pharmacology and Experimental Therapeutics, Windland Smith Rice Sudden Death Genomics Laboratory, Mayo Clinic, Rochester, Minnesota, USA
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15
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Lin Y, Zhao T, He S, Huang J, Liu Q, Yang Z, Qin J, Yu N, Lu H, Lin X. Compound and heterozygous mutations of KCNQ1 in long QT syndrome with familial history of unexplained sudden death: Identified by analysis of whole exome sequencing and predisposing genes. Ann Noninvasive Electrocardiol 2019; 25:e12694. [PMID: 31565860 PMCID: PMC7358849 DOI: 10.1111/anec.12694] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Accepted: 08/05/2019] [Indexed: 12/23/2022] Open
Abstract
Introduction Long QT syndrome (LQTS) increases the risk of life‐threatening arrhythmia in young individuals with structurally normal hearts. Sixteen genes such as the KCNQ1, KCNH2, and SCN5A have been reported for association with LQTS. Case presentation We identified the compound heterozygous mutations in the KCNQ1 gene at c. G527A (p.W176X) and c.G1765A (p.G589S) predicted as “damaging.” The in‐silico analysis showed that when compared to the characteristics of mRNA and protein of wild‐type KCNQ1, the mRNA of c.G527A mutation was significantly different in the centroid secondary structure. The subunit coded by W176X would lose the transmembrane domains S3–S6 and helices A‐D. The protein secondary structure of G589S was slightly shortened in helix structure; the protein physics‐chemical parameters of W176X and G589S significantly and slightly changed, respectively. Conclusions The compound heterozygous mutations of W176X and G589S coexisting in KCNQ1 gene of homologous chromosomes, resulting in more severe phenotype, are the likely pathogenic and genetic risks of LQTS and USD in this Chinese family.
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Affiliation(s)
- Yubi Lin
- Department of Cardiology and Cardiovascular Intervention, Interventional Medical Center, The Fifth Affiliated Hospital of Sun Yat-sen University, Zhuhai, China.,Guangdong Provincial Key Laboratory of Biomedical Imaging and Guangdong Provincial Engineering Research Center of Molecular Imaging, The Fifth Affiliated Hospital, Sun Yat-sen University, Zhuhai, China.,Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangdong Cardiovascular Institute, Guangdong Geriatrics Institute, Guangzhou, China
| | - Ting Zhao
- Department of Cardiology and Cardiovascular Intervention, Interventional Medical Center, The Fifth Affiliated Hospital of Sun Yat-sen University, Zhuhai, China
| | - Siqi He
- The Sixth Affiliated Hospital of Sun Yat-sen University, Guangzhou, China
| | - Jiana Huang
- The Sixth Affiliated Hospital of Sun Yat-sen University, Guangzhou, China
| | | | - Zhe Yang
- Department of Cardiology and Cardiovascular Intervention, Interventional Medical Center, The Fifth Affiliated Hospital of Sun Yat-sen University, Zhuhai, China
| | - Jiading Qin
- Department of Cardiology and Cardiovascular Intervention, Interventional Medical Center, The Fifth Affiliated Hospital of Sun Yat-sen University, Zhuhai, China
| | - Nan Yu
- Department of Clinical Laboratory, Zhujiang Hospital of Southern Medical University, Guangzhou, China
| | - Hongyun Lu
- Department of Endocrinology, The Fifth Affiliated Hospital of Sun Yat-sen University, Zhuhai, China
| | - Xiufang Lin
- Department of Cardiology and Cardiovascular Intervention, Interventional Medical Center, The Fifth Affiliated Hospital of Sun Yat-sen University, Zhuhai, China
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16
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Asatryan B, Medeiros-Domingo A. Molecular and genetic insights into progressive cardiac conduction disease. Europace 2019; 21:1145-1158. [DOI: 10.1093/europace/euz109] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2019] [Accepted: 03/27/2019] [Indexed: 12/14/2022] Open
Abstract
Abstract
Progressive cardiac conduction disease (PCCD) is often a primarily genetic disorder, with clinical and genetic overlaps with other inherited cardiac and metabolic diseases. A number of genes have been implicated in PCCD pathogenesis with or without structural heart disease or systemic manifestations. Precise genetic diagnosis contributes to risk stratification, better selection of specific therapy and allows familiar cascade screening. Cardiologists should be aware of the different phenotypes emerging from different gene-mutations and the potential risk of sudden cardiac death. Genetic forms of PCCD often overlap or coexist with other inherited heart diseases or manifest in the context of multisystem syndromes. Despite the significant advances in the knowledge of the genetic architecture of PCCD and overlapping diseases, in a measurable fraction of PCCD cases, including in familial clustering of disease, investigations of known cardiac disease-associated genes fail to reveal the underlying substrate, suggesting that new causal genes are yet to be discovered. Here, we provide insight into genetics and molecular mechanisms of PCCD and related diseases. We also highlight the phenotypic overlaps of PCCD with other inherited cardiac and metabolic diseases, present unmet challenges in clinical practice, and summarize the available therapeutic options for affected patients.
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Affiliation(s)
- Babken Asatryan
- Department of Cardiology, Inselspital, Bern University Hospital, Freiburgstrasse 8, Bern, Switzerland
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17
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Wilders R, Verkerk AO. Long QT Syndrome and Sinus Bradycardia-A Mini Review. Front Cardiovasc Med 2018; 5:106. [PMID: 30123799 PMCID: PMC6085426 DOI: 10.3389/fcvm.2018.00106] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2018] [Accepted: 07/16/2018] [Indexed: 12/16/2022] Open
Abstract
Congenital long-QT syndrome (LQTS) is an inherited cardiac disorder characterized by the prolongation of ventricular repolarization, susceptibility to Torsades de Pointes (TdP), and a risk for sudden death. Various types of congenital LQTS exist, all due to specific defects in ion channel-related genes. Interestingly, almost all of the ion channels affected by the various types of LQTS gene mutations are also expressed in the human sinoatrial node (SAN). It is therefore not surprising that LQTS is frequently associated with a change in basal heart rate (HR). However, current data on how the LQTS-associated ion channel defects result in impaired human SAN pacemaker activity are limited. In this mini-review, we provide an overview of known LQTS mutations with effects on HR and the underlying changes in expression and kinetics of ion channels. Sinus bradycardia has been reported in relation to a large number of LQTS mutations. However, the occurrence of both QT prolongation and sinus bradycardia on a family basis is almost completely limited to LQTS types 3 and 4 (LQT3 and Ankyrin-B syndrome, respectively). Furthermore, a clear causative role of this sinus bradycardia in cardiac events seems reserved to mutations underlying LQT3.
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Affiliation(s)
- Ronald Wilders
- Department of Medical Biology, Amsterdam University Medical Centers, Amsterdam, Netherlands
| | - Arie O Verkerk
- Department of Medical Biology, Amsterdam University Medical Centers, Amsterdam, Netherlands.,Department of Experimental Cardiology, Amsterdam University Medical Centers, Amsterdam, Netherlands
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18
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Wang J, Wang X, Ma Z, Yun K, Liu J, Chen D, Liu Z, Shi J, Li Z, Gao C, Du Q, Zhang G. A SNaPshot assay for detection of 45 mutations in the SCN5A gene in the Chinese Han Population. Electrophoresis 2018; 39:2270-2276. [DOI: 10.1002/elps.201800096] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2018] [Revised: 05/25/2018] [Accepted: 05/30/2018] [Indexed: 11/07/2022]
Affiliation(s)
- Jiaqi Wang
- School of Forensic Medicine; Shanxi Medical University; Taiyuan P. R. China
| | - Xudong Wang
- Forensic Science Engineering Research Center of Universities in Chongqing; Chongqing P. R. China
| | - Zhihua Ma
- Key Laboratory of Criminal Science and Technology of Chongqing City; Chongqing P. R. China
| | - Keming Yun
- School of Forensic Medicine; Shanxi Medical University; Taiyuan P. R. China
| | - Jinding Liu
- School of Forensic Medicine; Shanxi Medical University; Taiyuan P. R. China
| | - Deqing Chen
- School of Forensic Medicine; Shanxi Medical University; Taiyuan P. R. China
| | - Zidong Liu
- School of Forensic Medicine; Shanxi Medical University; Taiyuan P. R. China
| | - Jie Shi
- School of Forensic Medicine; Shanxi Medical University; Taiyuan P. R. China
| | - Zeqin Li
- School of Forensic Medicine; Shanxi Medical University; Taiyuan P. R. China
| | - Cairong Gao
- School of Forensic Medicine; Shanxi Medical University; Taiyuan P. R. China
| | - Qiuxiang Du
- School of Forensic Medicine; Shanxi Medical University; Taiyuan P. R. China
| | - Gengqian Zhang
- School of Forensic Medicine; Shanxi Medical University; Taiyuan P. R. China
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19
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Stramba-Badiale M, Karnad DR, Goulene KM, Panicker GK, Dagradi F, Spazzolini C, Kothari S, Lokhandwala YY, Schwartz PJ. For neonatal ECG screening there is no reason to relinquish old Bazett’s correction. Eur Heart J 2018; 39:2888-2895. [DOI: 10.1093/eurheartj/ehy284] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/22/2018] [Accepted: 04/27/2018] [Indexed: 11/12/2022] Open
Affiliation(s)
- Marco Stramba-Badiale
- Pediatric Arrhythmias Center, IRCCS Istituto Auxologico Italiano, Via Ariosto 9, 20145 Milan, Italy
| | - Dilip R Karnad
- Cardiac Safety Services, IQVIA, Research and Report Department, 602, VI Floor, Natraj, M. V. Road Junction, Western Express Highway, Andheri East, Mumbai 400 069, India
| | - Karine M Goulene
- Pediatric Arrhythmias Center, IRCCS Istituto Auxologico Italiano, Via Ariosto 9, 20145 Milan, Italy
| | - Gopi Krishna Panicker
- Cardiac Safety Services, IQVIA, Research and Report Department, 602, VI Floor, Natraj, M. V. Road Junction, Western Express Highway, Andheri East, Mumbai 400 069, India
| | - Federica Dagradi
- Center for Cardiac Arrhythmias of Genetic Origin, IRCCS Istituto Auxologico Italiano, Via Pier Lombardo 22, 20135 Milan, Italy
| | - Carla Spazzolini
- Center for Cardiac Arrhythmias of Genetic Origin, IRCCS Istituto Auxologico Italiano, Via Pier Lombardo 22, 20135 Milan, Italy
| | - Snehal Kothari
- Cardiac Safety Services, IQVIA, Research and Report Department, 602, VI Floor, Natraj, M. V. Road Junction, Western Express Highway, Andheri East, Mumbai 400 069, India
| | - Yash Y Lokhandwala
- Heart Institute (Cardiology, Cardiovascular & Thoracic Surgery), Dr Balabhai Nanavati Hospital, Swami Vivekanand Marg, Vile Parle West, Mumbai 400056, India
| | - Peter J Schwartz
- Center for Cardiac Arrhythmias of Genetic Origin, IRCCS Istituto Auxologico Italiano, Via Pier Lombardo 22, 20135 Milan, Italy
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20
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Deyawe A, Kasimova MA, Delemotte L, Loussouarn G, Tarek M. Studying Kv Channels Function using Computational Methods. Methods Mol Biol 2018; 1684:321-341. [PMID: 29058202 DOI: 10.1007/978-1-4939-7362-0_24] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
In recent years, molecular modeling techniques, combined with MD simulations, provided significant insights on voltage-gated (Kv) potassium channels intrinsic properties. Among the success stories are the highlight of molecular level details of the effects of mutations, the unraveling of several metastable intermediate states, and the influence of a particular lipid, PIP2, in the stability and the modulation of Kv channel function. These computational studies offered a detailed view that could not have been reached through experimental studies alone. With the increase of cross disciplinary studies, numerous experiments provided validation of these computational results, which endows an increase in the reliability of molecular modeling for the study of Kv channels. This chapter offers a description of the main techniques used to model Kv channels at the atomistic level.
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Affiliation(s)
- Audrey Deyawe
- Structure et Réactivité des Systèmes Moléculaires Complexes, CNRS, Université de Lorraine, Nancy, France
| | - Marina A Kasimova
- Structure et Réactivité des Systèmes Moléculaires Complexes, CNRS, Université de Lorraine, Nancy, France
| | - Lucie Delemotte
- Structure et Réactivité des Systèmes Moléculaires Complexes, CNRS, Université de Lorraine, Nancy, France
| | - Gildas Loussouarn
- L'institut du thorax, Inserm, CNRS, Université de Nantes, Nantes, France
| | - Mounir Tarek
- Structure et Réactivité des Systèmes Moléculaires Complexes, CNRS, Université de Lorraine, Nancy, France.
- CNRS, Unité Mixte de Recherches 7565, Université de Lorraine, Boulevard des Aiguillettes, BP 70239, 54506, Vandoeuvre-lès-Nancy, France.
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21
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Effect of age and gender on the QTc-interval in healthy individuals and patients with long-QT syndrome. Trends Cardiovasc Med 2017; 28:64-75. [PMID: 28869094 DOI: 10.1016/j.tcm.2017.07.012] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/11/2017] [Revised: 07/26/2017] [Accepted: 07/27/2017] [Indexed: 12/15/2022]
Abstract
Age- and gender-related differences in QTc-interval are most likely the result of changes in sex-specific hormones. Although the exact mechanisms and pathophysiology of sex hormones on the QTc-interval are not known, testosterone appears to shorten the QTc-interval. In females, however, there is a more complex interaction between progesterone and estrogen. In patients with an impaired repolarization, such as long-QT syndrome (LQTS), the effect of these sex hormones on the QTc-interval is more pronounced with a differing sensitivity between the LQTS genotypes.
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22
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Bdier AY, Al-Ghamdi S, Verma PK, Dagriri K, Alshehri B, Jiman OA, Ahmed SE, Wilde AAM, Bhuiyan ZA, Al-Aama JY. Autosomal recessive long QT syndrome, type 1 in eight families from Saudi Arabia. Mol Genet Genomic Med 2017; 5:592-601. [PMID: 28944242 PMCID: PMC5606890 DOI: 10.1002/mgg3.305] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2017] [Revised: 05/18/2017] [Accepted: 05/22/2017] [Indexed: 01/08/2023] Open
Abstract
Background One of the most common primary cardiac arrhythmia syndromes is autosomal dominant long QT syndrome, type 1 (LQT1), chiefly caused by mono‐allelic mutations in the KCNQ1 gene. Bi‐allelic mutations in the KCNQ1 gene are causal to Jervell and Lange‐Nielsen syndrome (JLNS), characterized by severe and early‐onset arrhythmias with prolonged QTc interval on surface ECG and sensorineural deafness. Occasionally, bi‐allelic mutations in KCNQ1 are also found in patients without any deafness, referred to as autosomal recessive long QT syndrome, type 1 (AR LQT1). Methods We used Sanger sequencing to detect the pathogenic mutations in KCNQ1 gene in eight families from Saudi Arabia with autosomal recessive LQT1. Results We have detected pathogenic mutations in all eight families, two of the mutations are founder mutations, which are c.387‐5T>A and p.Val172Met/p.Arg293Cys (in cis). QTc and cardiac phenotype was found to be pronounced in all the probands comparable to the cardiac phenotype in JLNS patients. Heterozygous carriers for these mutations did not exhibit any clinical phenotype, but a significant number of them have sinus bradycardia. Conclusion To the best of our knowledge, this is the first description of a large series of patients with familial autosomal recessive LQT, type 1. These mutations could be used for targeted screening in cardiac arrhythmia patients in Saudi Arabia and in people of Arabic ancestry.
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Affiliation(s)
- Amnah Y Bdier
- Department of Biological SciencesFaculty of ScienceKing Abdulaziz UniversityJeddahSaudi Arabia.,Princess Al Jawhara Albrahim Center of Excellence in Research of Hereditary DisordersKing Abdulaziz UniversityJeddahSaudi Arabia
| | - Saleh Al-Ghamdi
- Department of Genetic MedicineKing Abdulaziz UniversityJeddahSaudi Arabia
| | - Prashant K Verma
- Princess Al Jawhara Albrahim Center of Excellence in Research of Hereditary DisordersKing Abdulaziz UniversityJeddahSaudi Arabia.,Department of CardiologyNGHRiyadhSaudi Arabia
| | - Khalid Dagriri
- Department of Pediatric CardiologyPrince Sultan Cardiac CenterRiyadhSaudi Arabia
| | - Bandar Alshehri
- Princess Al Jawhara Albrahim Center of Excellence in Research of Hereditary DisordersKing Abdulaziz UniversityJeddahSaudi Arabia
| | - Omamah A Jiman
- Department of Genetic MedicineKing Abdulaziz UniversityJeddahSaudi Arabia
| | - Sherif E Ahmed
- Department of Biological SciencesFaculty of ScienceKing Abdulaziz UniversityJeddahSaudi Arabia.,Princess Al Jawhara Albrahim Center of Excellence in Research of Hereditary DisordersKing Abdulaziz UniversityJeddahSaudi Arabia.,Department of GeneticsFaculty of AgricultureAin shams UniversityCairoEgypt
| | - Arthur A M Wilde
- Department of CardiologyAcademic Medical CenterUniversity of AmsterdamAmsterdamthe Netherlands
| | - Zahurul A Bhuiyan
- Laboratoire de Génétique MoléculaireService de médecine génétiqueCHUVLausanneSwitzerland
| | - Jumana Y Al-Aama
- Princess Al Jawhara Albrahim Center of Excellence in Research of Hereditary DisordersKing Abdulaziz UniversityJeddahSaudi Arabia.,Department of CardiologyNGHRiyadhSaudi Arabia
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23
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Vink AS, Clur SAB, Geskus RB, Blank AC, De Kezel CCA, Yoshinaga M, Hofman N, Wilde AAM, Blom NA. Effect of Age and Sex on the QTc Interval in Children and Adolescents With Type 1 and 2 Long-QT Syndrome. Circ Arrhythm Electrophysiol 2017; 10:CIRCEP.116.004645. [PMID: 28356306 DOI: 10.1161/circep.116.004645] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/05/2016] [Accepted: 01/26/2017] [Indexed: 01/16/2023]
Abstract
BACKGROUND In congenital long-QT syndrome, age, sex, and genotype have been associated with cardiac events, but their effect on the trend in QTc interval has never been established. We, therefore, aimed to assess the effect of age and sex on the QTc interval in children and adolescents with type 1 (LQT1) and type 2 (LQT2) long-QT syndrome. METHODS AND RESULTS QTc intervals of 12-lead resting electrocardiograms were determined, and trends over time were analyzed using a linear mixed-effects model. The study included 278 patients with a median follow-up of 4 years (interquartile range, 1-9) and a median number of 6 (interquartile range, 2-10) electrocardiograms per patient. Both LQT1 and LQT2 male patients showed QTc interval shortening after the onset of puberty. In LQT2 male patients, this was preceded by a progressive QTc interval prolongation. In LQT1, after the age of 12 years, male patients had a significantly shorter QTc interval than female patients. In LQT2, during the first years of life and from 14 to 26 years, male patients had a significantly shorter QTc interval than female patients. On the contrary, between 5 and 14 years, LQT2 male patients had significantly longer QTc interval than LQT2 female patients. CONCLUSIONS There is a significant effect of age and sex on the QTc interval in long-QT syndrome, with a unique pattern per genotype. The age of 12 to 14 years is an important transitional period. In the risk stratification and management of long-QT syndrome patients, clinicians should be aware of these age-, sex-, and genotype-related trends in QTc interval and especially the important role of the onset of puberty.
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Affiliation(s)
- Arja S Vink
- From the Department of Cardiology, Heart Centre (A.S.V., N.H., A.A.M.W.), Department of Pediatric Cardiology, Emma Children's Hospital (A.S.V., S.-A.B.C., N.A.B.), and Department of Clinical Epidemiology, Biostatistics and Bioinformatics (R.B.G.), Academic Medical Centre, Amsterdam, The Netherlands; Department of Pediatric Cardiology, Wilhelmina Children's Hospital, University Medical Centre Utrecht, The Netherlands (A.C.B.); Department of Pediatrics, Elisabeth-TweeSteden Hospital, Tilburg, The Netherlands (C.C.A.D.K.); Department of Pediatrics, National Hospital Organization Kagoshima Medical Center, Japan (M.Y.); and Department of Pediatric Cardiology, Willem-Alexander Children's Hospital, University Medical Centre Leiden, The Netherlands (N.A.B.).
| | - Sally-Ann B Clur
- From the Department of Cardiology, Heart Centre (A.S.V., N.H., A.A.M.W.), Department of Pediatric Cardiology, Emma Children's Hospital (A.S.V., S.-A.B.C., N.A.B.), and Department of Clinical Epidemiology, Biostatistics and Bioinformatics (R.B.G.), Academic Medical Centre, Amsterdam, The Netherlands; Department of Pediatric Cardiology, Wilhelmina Children's Hospital, University Medical Centre Utrecht, The Netherlands (A.C.B.); Department of Pediatrics, Elisabeth-TweeSteden Hospital, Tilburg, The Netherlands (C.C.A.D.K.); Department of Pediatrics, National Hospital Organization Kagoshima Medical Center, Japan (M.Y.); and Department of Pediatric Cardiology, Willem-Alexander Children's Hospital, University Medical Centre Leiden, The Netherlands (N.A.B.)
| | - Ronald B Geskus
- From the Department of Cardiology, Heart Centre (A.S.V., N.H., A.A.M.W.), Department of Pediatric Cardiology, Emma Children's Hospital (A.S.V., S.-A.B.C., N.A.B.), and Department of Clinical Epidemiology, Biostatistics and Bioinformatics (R.B.G.), Academic Medical Centre, Amsterdam, The Netherlands; Department of Pediatric Cardiology, Wilhelmina Children's Hospital, University Medical Centre Utrecht, The Netherlands (A.C.B.); Department of Pediatrics, Elisabeth-TweeSteden Hospital, Tilburg, The Netherlands (C.C.A.D.K.); Department of Pediatrics, National Hospital Organization Kagoshima Medical Center, Japan (M.Y.); and Department of Pediatric Cardiology, Willem-Alexander Children's Hospital, University Medical Centre Leiden, The Netherlands (N.A.B.)
| | - Andreas C Blank
- From the Department of Cardiology, Heart Centre (A.S.V., N.H., A.A.M.W.), Department of Pediatric Cardiology, Emma Children's Hospital (A.S.V., S.-A.B.C., N.A.B.), and Department of Clinical Epidemiology, Biostatistics and Bioinformatics (R.B.G.), Academic Medical Centre, Amsterdam, The Netherlands; Department of Pediatric Cardiology, Wilhelmina Children's Hospital, University Medical Centre Utrecht, The Netherlands (A.C.B.); Department of Pediatrics, Elisabeth-TweeSteden Hospital, Tilburg, The Netherlands (C.C.A.D.K.); Department of Pediatrics, National Hospital Organization Kagoshima Medical Center, Japan (M.Y.); and Department of Pediatric Cardiology, Willem-Alexander Children's Hospital, University Medical Centre Leiden, The Netherlands (N.A.B.)
| | - Charlotte C A De Kezel
- From the Department of Cardiology, Heart Centre (A.S.V., N.H., A.A.M.W.), Department of Pediatric Cardiology, Emma Children's Hospital (A.S.V., S.-A.B.C., N.A.B.), and Department of Clinical Epidemiology, Biostatistics and Bioinformatics (R.B.G.), Academic Medical Centre, Amsterdam, The Netherlands; Department of Pediatric Cardiology, Wilhelmina Children's Hospital, University Medical Centre Utrecht, The Netherlands (A.C.B.); Department of Pediatrics, Elisabeth-TweeSteden Hospital, Tilburg, The Netherlands (C.C.A.D.K.); Department of Pediatrics, National Hospital Organization Kagoshima Medical Center, Japan (M.Y.); and Department of Pediatric Cardiology, Willem-Alexander Children's Hospital, University Medical Centre Leiden, The Netherlands (N.A.B.)
| | - Masao Yoshinaga
- From the Department of Cardiology, Heart Centre (A.S.V., N.H., A.A.M.W.), Department of Pediatric Cardiology, Emma Children's Hospital (A.S.V., S.-A.B.C., N.A.B.), and Department of Clinical Epidemiology, Biostatistics and Bioinformatics (R.B.G.), Academic Medical Centre, Amsterdam, The Netherlands; Department of Pediatric Cardiology, Wilhelmina Children's Hospital, University Medical Centre Utrecht, The Netherlands (A.C.B.); Department of Pediatrics, Elisabeth-TweeSteden Hospital, Tilburg, The Netherlands (C.C.A.D.K.); Department of Pediatrics, National Hospital Organization Kagoshima Medical Center, Japan (M.Y.); and Department of Pediatric Cardiology, Willem-Alexander Children's Hospital, University Medical Centre Leiden, The Netherlands (N.A.B.)
| | - Nynke Hofman
- From the Department of Cardiology, Heart Centre (A.S.V., N.H., A.A.M.W.), Department of Pediatric Cardiology, Emma Children's Hospital (A.S.V., S.-A.B.C., N.A.B.), and Department of Clinical Epidemiology, Biostatistics and Bioinformatics (R.B.G.), Academic Medical Centre, Amsterdam, The Netherlands; Department of Pediatric Cardiology, Wilhelmina Children's Hospital, University Medical Centre Utrecht, The Netherlands (A.C.B.); Department of Pediatrics, Elisabeth-TweeSteden Hospital, Tilburg, The Netherlands (C.C.A.D.K.); Department of Pediatrics, National Hospital Organization Kagoshima Medical Center, Japan (M.Y.); and Department of Pediatric Cardiology, Willem-Alexander Children's Hospital, University Medical Centre Leiden, The Netherlands (N.A.B.)
| | - Arthur A M Wilde
- From the Department of Cardiology, Heart Centre (A.S.V., N.H., A.A.M.W.), Department of Pediatric Cardiology, Emma Children's Hospital (A.S.V., S.-A.B.C., N.A.B.), and Department of Clinical Epidemiology, Biostatistics and Bioinformatics (R.B.G.), Academic Medical Centre, Amsterdam, The Netherlands; Department of Pediatric Cardiology, Wilhelmina Children's Hospital, University Medical Centre Utrecht, The Netherlands (A.C.B.); Department of Pediatrics, Elisabeth-TweeSteden Hospital, Tilburg, The Netherlands (C.C.A.D.K.); Department of Pediatrics, National Hospital Organization Kagoshima Medical Center, Japan (M.Y.); and Department of Pediatric Cardiology, Willem-Alexander Children's Hospital, University Medical Centre Leiden, The Netherlands (N.A.B.)
| | - Nico A Blom
- From the Department of Cardiology, Heart Centre (A.S.V., N.H., A.A.M.W.), Department of Pediatric Cardiology, Emma Children's Hospital (A.S.V., S.-A.B.C., N.A.B.), and Department of Clinical Epidemiology, Biostatistics and Bioinformatics (R.B.G.), Academic Medical Centre, Amsterdam, The Netherlands; Department of Pediatric Cardiology, Wilhelmina Children's Hospital, University Medical Centre Utrecht, The Netherlands (A.C.B.); Department of Pediatrics, Elisabeth-TweeSteden Hospital, Tilburg, The Netherlands (C.C.A.D.K.); Department of Pediatrics, National Hospital Organization Kagoshima Medical Center, Japan (M.Y.); and Department of Pediatric Cardiology, Willem-Alexander Children's Hospital, University Medical Centre Leiden, The Netherlands (N.A.B.)
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Smith JD, Vinocur JM. Atypical long QT syndrome phenotype in heterozygous/homozygous KCNQ1 Ala590Thr. HeartRhythm Case Rep 2017; 3:219-223. [PMID: 28491806 PMCID: PMC5419811 DOI: 10.1016/j.hrcr.2017.01.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
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Ioakeimidis NS, Papamitsou T, Meditskou S, Iakovidou-Kritsi Z. Sudden infant death syndrome due to long QT syndrome: a brief review of the genetic substrate and prevalence. ACTA ACUST UNITED AC 2017; 24:6. [PMID: 28316956 PMCID: PMC5348737 DOI: 10.1186/s40709-017-0063-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2016] [Accepted: 03/02/2017] [Indexed: 01/30/2023]
Abstract
The pathophysiological mechanisms which lead to sudden infant death syndrome (SIDS) are not completely understood. Cardiac channelopathies are a well-established causative factor with long QT syndrome (LQTS) being the most frequent one, accounting for approximately 12% of SIDS cases. The genetic substrate of the above arrhythmogenic syndrome has been thoroughly described but only specific gene mutations or polymorphisms have been identified as SIDS causative. The review will focus on the prevalence of LQTS-induced SIDS or near-SIDS cases and the mutations held responsible. A literature search was performed in PubMed and Scopus electronic databases. Search terms used were: long QT syndrome, channelopathies, QT prolongation, cardiac ion channels. The above-mentioned search terms were always combined with the term: sudden infant death syndrome. Study types considered eligible were: case–control, family pedigree analysis, case reports. The prevalence of LQTS-induced SIDS according to six broad genetic studies ranges from 3.9 to 20.6%, with an average of 12%. Since LQTS can be effectively managed, LQTS-related SIDS cases could be prevented, provided that a screening method is efficient enough to detect all the affected infants.
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Affiliation(s)
- Nikolaos S Ioakeimidis
- Laboratory of Histology and Embryology, Faculty of Medicine, Aristotle University of Thessaloniki, Aristotle University of Thessaloniki Campus, 54124 Thessaloníki, Greece
| | - Theodora Papamitsou
- Laboratory of Histology and Embryology, Faculty of Medicine, Aristotle University of Thessaloniki, Aristotle University of Thessaloniki Campus, 54124 Thessaloníki, Greece
| | - Soultana Meditskou
- Laboratory of Histology and Embryology, Faculty of Medicine, Aristotle University of Thessaloniki, Aristotle University of Thessaloniki Campus, 54124 Thessaloníki, Greece
| | - Zafiroula Iakovidou-Kritsi
- Laboratory of Medical Biology-Genetics, Faculty of Medicine, Aristotle University of Thessaloniki, Aristotle University of Thessaloniki Campus, 54124 Thessaloníki, Greece
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26
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Fernández-Falgueras A, Sarquella-Brugada G, Brugada J, Brugada R, Campuzano O. Cardiac Channelopathies and Sudden Death: Recent Clinical and Genetic Advances. BIOLOGY 2017; 6:biology6010007. [PMID: 28146053 PMCID: PMC5372000 DOI: 10.3390/biology6010007] [Citation(s) in RCA: 69] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/22/2016] [Revised: 01/17/2017] [Accepted: 01/20/2017] [Indexed: 12/19/2022]
Abstract
Sudden cardiac death poses a unique challenge to clinicians because it may be the only symptom of an inherited heart condition. Indeed, inherited heart diseases can cause sudden cardiac death in older and younger individuals. Two groups of familial diseases are responsible for sudden cardiac death: cardiomyopathies (mainly hypertrophic cardiomyopathy, dilated cardiomyopathy, and arrhythmogenic cardiomyopathy) and channelopathies (mainly long QT syndrome, Brugada syndrome, short QT syndrome, and catecholaminergic polymorphic ventricular tachycardia). This review focuses on cardiac channelopathies, which are characterized by lethal arrhythmias in the structurally normal heart, incomplete penetrance, and variable expressivity. Arrhythmias in these diseases result from pathogenic variants in genes encoding cardiac ion channels or associated proteins. Due to a lack of gross structural changes in the heart, channelopathies are often considered as potential causes of death in otherwise unexplained forensic autopsies. The asymptomatic nature of channelopathies is cause for concern in family members who may be carrying genetic risk factors, making the identification of these genetic factors of significant clinical importance.
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Affiliation(s)
| | | | - Josep Brugada
- Arrhythmias Unit, Hospital Sant Joan de Déu, University of Barcelona, Barcelona 08950, Spain.
| | - Ramon Brugada
- Cardiovascular Genetics Center, IDIBGI, Girona 17190, Spain.
- Medical Sciences Department, School of Medicine, University of Girona, Girona 17071, Spain.
- Familial Cardiomyopathies Unit, Hospital Josep Trueta, Girona 17007, Spain.
| | - Oscar Campuzano
- Cardiovascular Genetics Center, IDIBGI, Girona 17190, Spain.
- Medical Sciences Department, School of Medicine, University of Girona, Girona 17071, Spain.
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27
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Ozawa J, Ohno S, Hisamatsu T, Itoh H, Makiyama T, Suzuki H, Saitoh A, Horie M. Pediatric Cohort With Long QT Syndrome - KCNH2 Mutation Carriers Present Late Onset But Severe Symptoms. Circ J 2016; 80:696-702. [PMID: 26823142 DOI: 10.1253/circj.cj-15-0933] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
BACKGROUND In children with long QT syndrome (LQTS), risk factors for cardiac events have been reported, but age-, gender- and genotype-related differences in prognosis remain unknown in Asian countries. METHODS AND RESULTS The study examined clinical prognosis at age between 1 and 20 years in 496 LQTS patients who were genotyped as either of LQT1-3 (male, n=206). Heterozygous mutations were observed in 3 major responsible genes:KCNQ1in271,KCNH2in 192, andSCN5Ain 33 patients. LQTS-associated events were classified into 3 categories: (1) syncope (n=133); (2) repetitive torsade de pointes (TdP, n=3); and (3) cardiopulmonary arrest (CPA, n=4). The risk of cardiac events was significantly lower in LQT1 girls than boys≤12 years (HR, 0.55), whereas LQT2 female patients ≥13 years had the higher risk of cardiac events than male patients (HR, 4.60). Patients in the repetitive TdP or CPA group included 1 LQT1 female patient, 1 LQT2 male patient, and 5 LQT2 female patients. All LQT2 patients in these groups had TdP repeatedly immediately after the antecedent event. In addition, all 5 female LQT2 patients in these groups had the event after or near puberty. CONCLUSIONS Female LQT2 children might have repeated TdP shortly after prior events, especially after puberty. (Circ J 2016; 80: 696-702).
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Affiliation(s)
- Junichi Ozawa
- Department of Cardiovascular and Respiratory Medicine, Shiga University of Medical Science
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28
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Cuneo BF, Strasburger JF. We only find what we look for: fetal heart rate and the diagnosis of long-QT syndrome. Circ Arrhythm Electrophysiol 2015; 8:760-2. [PMID: 26286300 PMCID: PMC4552049 DOI: 10.1161/circep.115.003196] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Long QT syndrome (LQTS), an inherited channelopathy, is a common cause of arrhythmic death in infants, children and young adults. Although many LQTS genes have been identified, most (~75%) of LQTS mutations are found in KCNQ1, KCNH2 or SCN5A. In most cases, treatment for LQTS is successful and modifies the risk of life-threatening arrhythmias; thus, making the correct diagnosis is important. The diagnosis of LQTS is made by the measurement of a prolonged QT interval on the standard ECG; family history or characteristic arrhythmia features are used to strengthen the diagnosis and genetic testing confirms the diagnosis.
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Affiliation(s)
- Bettina F Cuneo
- From the Children's Hospital Colorado Heart Institute, Department of Pediatrics, The University of Colorado School of Medicine, Aurora (B.F.C.); and Division of Cardiology, Department of Pediatrics, Children's Hospital of Wisconsin, The Medical College of Wisconsin, Milwaukee (J.F.S.).
| | - Janette F Strasburger
- From the Children's Hospital Colorado Heart Institute, Department of Pediatrics, The University of Colorado School of Medicine, Aurora (B.F.C.); and Division of Cardiology, Department of Pediatrics, Children's Hospital of Wisconsin, The Medical College of Wisconsin, Milwaukee (J.F.S.)
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29
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Winbo A, Fosdal I, Lindh M, Diamant UB, Persson J, Wettrell G, Rydberg A. Third Trimester Fetal Heart Rate Predicts Phenotype and Mutation Burden in the Type 1 Long QT Syndrome. Circ Arrhythm Electrophysiol 2015; 8:806-14. [DOI: 10.1161/circep.114.002552] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/05/2014] [Accepted: 05/08/2015] [Indexed: 11/16/2022]
Affiliation(s)
- Annika Winbo
- From the Department of Clinical Sciences, Pediatrics (A.W., M.L., J.P., A.R.) and Department of Public Health and Clinical Medicine, Heart Centre (U.-B.D.), Umeå University, Umeå, Sweden; Pediatric Clinic, Visby Hospital, Visby, Sweden (I.F.); Department of Pediatrics and Pediatric Cardiology, University of Lund, Lund, Sweden (G.W.); and Department of Physiology, University of Auckland, Auckland, New Zealand (A.W.)
| | - Inger Fosdal
- From the Department of Clinical Sciences, Pediatrics (A.W., M.L., J.P., A.R.) and Department of Public Health and Clinical Medicine, Heart Centre (U.-B.D.), Umeå University, Umeå, Sweden; Pediatric Clinic, Visby Hospital, Visby, Sweden (I.F.); Department of Pediatrics and Pediatric Cardiology, University of Lund, Lund, Sweden (G.W.); and Department of Physiology, University of Auckland, Auckland, New Zealand (A.W.)
| | - Maria Lindh
- From the Department of Clinical Sciences, Pediatrics (A.W., M.L., J.P., A.R.) and Department of Public Health and Clinical Medicine, Heart Centre (U.-B.D.), Umeå University, Umeå, Sweden; Pediatric Clinic, Visby Hospital, Visby, Sweden (I.F.); Department of Pediatrics and Pediatric Cardiology, University of Lund, Lund, Sweden (G.W.); and Department of Physiology, University of Auckland, Auckland, New Zealand (A.W.)
| | - Ulla-Britt Diamant
- From the Department of Clinical Sciences, Pediatrics (A.W., M.L., J.P., A.R.) and Department of Public Health and Clinical Medicine, Heart Centre (U.-B.D.), Umeå University, Umeå, Sweden; Pediatric Clinic, Visby Hospital, Visby, Sweden (I.F.); Department of Pediatrics and Pediatric Cardiology, University of Lund, Lund, Sweden (G.W.); and Department of Physiology, University of Auckland, Auckland, New Zealand (A.W.)
| | - Johan Persson
- From the Department of Clinical Sciences, Pediatrics (A.W., M.L., J.P., A.R.) and Department of Public Health and Clinical Medicine, Heart Centre (U.-B.D.), Umeå University, Umeå, Sweden; Pediatric Clinic, Visby Hospital, Visby, Sweden (I.F.); Department of Pediatrics and Pediatric Cardiology, University of Lund, Lund, Sweden (G.W.); and Department of Physiology, University of Auckland, Auckland, New Zealand (A.W.)
| | - Göran Wettrell
- From the Department of Clinical Sciences, Pediatrics (A.W., M.L., J.P., A.R.) and Department of Public Health and Clinical Medicine, Heart Centre (U.-B.D.), Umeå University, Umeå, Sweden; Pediatric Clinic, Visby Hospital, Visby, Sweden (I.F.); Department of Pediatrics and Pediatric Cardiology, University of Lund, Lund, Sweden (G.W.); and Department of Physiology, University of Auckland, Auckland, New Zealand (A.W.)
| | - Annika Rydberg
- From the Department of Clinical Sciences, Pediatrics (A.W., M.L., J.P., A.R.) and Department of Public Health and Clinical Medicine, Heart Centre (U.-B.D.), Umeå University, Umeå, Sweden; Pediatric Clinic, Visby Hospital, Visby, Sweden (I.F.); Department of Pediatrics and Pediatric Cardiology, University of Lund, Lund, Sweden (G.W.); and Department of Physiology, University of Auckland, Auckland, New Zealand (A.W.)
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30
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Polyunsaturated fatty acid analogs act antiarrhythmically on the cardiac IKs channel. Proc Natl Acad Sci U S A 2015; 112:5714-9. [PMID: 25901329 DOI: 10.1073/pnas.1503488112] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Polyunsaturated fatty acids (PUFAs) affect cardiac excitability. Kv7.1 and the β-subunit KCNE1 form the cardiac IKs channel that is central for cardiac repolarization. In this study, we explore the prospects of PUFAs as IKs channel modulators. We report that PUFAs open Kv7.1 via an electrostatic mechanism. Both the polyunsaturated acyl tail and the negatively charged carboxyl head group are required for PUFAs to open Kv7.1. We further show that KCNE1 coexpression abolishes the PUFA effect on Kv7.1 by promoting PUFA protonation. PUFA analogs with a decreased pKa value, to preserve their negative charge at neutral pH, restore the sensitivity to open IKs channels. PUFA analogs with a positively charged head group inhibit IKs channels. These different PUFA analogs could be developed into drugs to treat cardiac arrhythmias. In support of this possibility, we show that PUFA analogs act antiarrhythmically in embryonic rat cardiomyocytes and in isolated perfused hearts from guinea pig.
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31
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Schweigmann U, Biliczki P, Ramirez RJ, Marschall C, Takac I, Brandes RP, Kotzot D, Girmatsion Z, Hohnloser SH, Ehrlich JR. Elevated heart rate triggers action potential alternans and sudden death. translational study of a homozygous KCNH2 mutation. PLoS One 2014; 9:e103150. [PMID: 25140878 PMCID: PMC4139196 DOI: 10.1371/journal.pone.0103150] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2014] [Accepted: 06/27/2014] [Indexed: 01/08/2023] Open
Abstract
BACKGROUND Long QT syndrome (LQTS) leads to arrhythmic events and increased risk for sudden cardiac death (SCD). Homozygous KCNH2 mutations underlying LQTS-2 have previously been termed "human HERG knockout" and typically express severe phenotypes. We studied genotype-phenotype correlations of an LQTS type 2 mutation identified in the homozygous index patient from a consanguineous Turkish family after his brother died suddenly during febrile illness. METHODS AND RESULTS Clinical work-up, DNA sequencing, mutagenesis, cell culture, patch-clamp, in silico mathematical modelling, protein biochemistry, confocal microscopy were performed. Genetic analysis revealed a homozygous C-terminal KCNH2 mutation (p.R835Q) in the index patient (QTc ∼506 ms with notched T waves). Parents were I° cousins - both heterozygous for the mutation and clinically unremarkable (QTc ∼447 ms, father and ∼396 ms, mother). Heterologous expression of KCNH2-R835Q showed mildly reduced current amplitudes. Biophysical properties of ionic currents were also only nominally changed with slight acceleration of deactivation and more negative V50 in R835Q-currents. Protein biochemistry and confocal microscopy revealed similar expression patterns and trafficking of WT and R835Q, even at elevated temperature. In silico analysis demonstrated mildly prolonged ventricular action potential duration (APD) compared to WT at a cycle length of 1000 ms. At a cycle length of 350 ms M-cell APD remained stable in WT, but displayed APD alternans in R835Q. CONCLUSION Kv11.1 channels affected by the C-terminal R835Q mutation display mildly modified biophysical properties, but leads to M-cell APD alternans with elevated heart rate and could precipitate SCD under specific clinical circumstances associated with high heart rates.
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Affiliation(s)
| | - Peter Biliczki
- Division of Clinical Electrophysiology, Goethe University, Frankfurt, Germany
- Div. of Cardiology, Deutsche Klinik für Diagnostik, Wiesbaden, Germany
| | - Rafael J. Ramirez
- Center for Arrhythmia Research, University of Michigan, Ann Arbor, Michigan, United States of America
| | | | - Ina Takac
- Institute of Cardiovascular Physiology, Goethe University, Frankfurt, Germany
| | - Ralf P. Brandes
- Institute of Cardiovascular Physiology, Goethe University, Frankfurt, Germany
| | - Dieter Kotzot
- Section for Human Genetics, Innsbruck Medical University, Innsbruck, Austria
| | - Zenawit Girmatsion
- Division of Clinical Electrophysiology, Goethe University, Frankfurt, Germany
| | - Stefan H. Hohnloser
- Division of Clinical Electrophysiology, Goethe University, Frankfurt, Germany
| | - Joachim R. Ehrlich
- Division of Clinical Electrophysiology, Goethe University, Frankfurt, Germany
- Div. of Cardiology, Deutsche Klinik für Diagnostik, Wiesbaden, Germany
- * E-mail:
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32
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Anuwutnavin S, Wanitpongpan P, Chungsomprasong P, Soongswang J, Srisantiroj N, Wataganara T. Fetal long QT syndrome manifested as atrioventricular block and ventricular tachycardia: a case report and a review of the literature. Pediatr Cardiol 2014; 34:1955-62. [PMID: 22987108 DOI: 10.1007/s00246-012-0507-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/10/2012] [Accepted: 08/26/2012] [Indexed: 11/30/2022]
Abstract
Fetal onset of congenital long QT syndrome (LQTS) is a rare manifestation, and prenatal diagnosis is difficult. This report describes a boy who presented with both atrioventricular (AV) block and ventricular tachycardia during the antenatal period. The early postnatal electrocardiogram showed prolongation of the QT interval and AV block, subsequently leading to a polymorphic ventricular tachycardia torsade de pointes. This unique feature of congenital LQTS has a poor outcome, but the boy was successfully treated with beta-blockers and implantation of an automated cardioverter-defibrillator. The intrauterine manifestation of fetal AV block and ventricular tachycardia should raise a high suspicion of congenital LQTS, and the strong association with a malignant clinical course should warrant special evaluation. The literature on the prenatal diagnosis, fetal therapy, and neonatal outcome of this condition also are reviewed.
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Affiliation(s)
- Sanitra Anuwutnavin
- Division of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, Faculty of Medicine Siriraj Hospital, Mahidol University, 2 Prannok Road, Bangkoknoi, Bangkok, 10700, Thailand,
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33
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Kinoshita K, Komatsu T, Nishide K, Hata Y, Hisajima N, Takahashi H, Kimoto K, Aonuma K, Tsushima E, Tabata T, Yoshida T, Mori H, Nishida K, Yamaguchi Y, Ichida F, Fukurotani K, Inoue H, Nishida N. A590T mutation in KCNQ1 C-terminal helix D decreases IKs channel trafficking and function but not Yotiao interaction. J Mol Cell Cardiol 2014; 72:273-80. [PMID: 24713462 DOI: 10.1016/j.yjmcc.2014.03.019] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/01/2013] [Revised: 02/28/2014] [Accepted: 03/26/2014] [Indexed: 12/21/2022]
Abstract
KCNQ1 encodes the α subunit of the voltage-gated channel that mediates the cardiac slow delayed rectifier K(+) current (IKs). Here, we report a KCNQ1 allele encoding an A590T mutation [KCNQ1(A590T)] found in a 39-year-old female with a mild QT prolongation. A590 is located in the C-terminal α helical region of KCNQ1 that mediates subunit tetramerization, membrane trafficking, and interaction with Yotiao. This interaction is known to be required for the proper modulation of IKs by cAMP. Since previous studies reported that mutations in the vicinity of A590 impair IKs channel surface expression and function, we examined whether and how the A590T mutation affects the IKs channel. Electrophysiological measurements in HEK-293T cells showed that the A590T mutation caused a reduction in IKs density and a right-shift of the current-voltage relation of channel activation. Immunocytochemical and immunoblot analyses showed the reduced cell surface expression of KCNQ1(A590T) subunit and its rescue by coexpression of the wild-type KCNQ1 [KCNQ1(WT)] subunit. Moreover, KCNQ1(A590T) subunit interacted with Yotiao and had a cAMP-responsiveness comparable to that of KCNQ1(WT) subunit. These findings indicate that the A590 of KCNQ1 subunit plays important roles in the maintenance of channel surface expression and function via a novel mechanism independent of interaction with Yotiao.
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Affiliation(s)
- Koshi Kinoshita
- Department of Legal Medicine, Graduate School of Medical and Pharmaceutical Sciences, University of Toyama, 2630 Sugitani, Toyama, Toyama 930-0194, Japan
| | - Takuto Komatsu
- Laboratory for Neural Information Technology, Graduate School of Sciences and Engineering, University of Toyama, 3190 Gofuku, Toyama, Toyama 930-8555, Japan
| | - Kohki Nishide
- Laboratory for Neural Information Technology, Graduate School of Sciences and Engineering, University of Toyama, 3190 Gofuku, Toyama, Toyama 930-8555, Japan
| | - Yukiko Hata
- Department of Legal Medicine, Graduate School of Medical and Pharmaceutical Sciences, University of Toyama, 2630 Sugitani, Toyama, Toyama 930-0194, Japan
| | - Nozomi Hisajima
- Laboratory for Neural Information Technology, Graduate School of Sciences and Engineering, University of Toyama, 3190 Gofuku, Toyama, Toyama 930-8555, Japan
| | - Hiroyuki Takahashi
- Laboratory for Neural Information Technology, Graduate School of Sciences and Engineering, University of Toyama, 3190 Gofuku, Toyama, Toyama 930-8555, Japan
| | - Katsuya Kimoto
- Laboratory for Neural Information Technology, Graduate School of Sciences and Engineering, University of Toyama, 3190 Gofuku, Toyama, Toyama 930-8555, Japan
| | - Kei Aonuma
- Laboratory for Neural Information Technology, Graduate School of Sciences and Engineering, University of Toyama, 3190 Gofuku, Toyama, Toyama 930-8555, Japan
| | - Eikichi Tsushima
- Laboratory for Neural Information Technology, Graduate School of Sciences and Engineering, University of Toyama, 3190 Gofuku, Toyama, Toyama 930-8555, Japan
| | - Toshihide Tabata
- Laboratory for Neural Information Technology, Graduate School of Sciences and Engineering, University of Toyama, 3190 Gofuku, Toyama, Toyama 930-8555, Japan
| | - Tomoyuki Yoshida
- Department of Molecular Neurosciences, Graduate School of Medical and Pharmaceutical Sciences, University of Toyama, 2630 Sugitani, Toyama, Toyama 930-0194, Japan
| | - Hisashi Mori
- Department of Molecular Neurosciences, Graduate School of Medical and Pharmaceutical Sciences, University of Toyama, 2630 Sugitani, Toyama, Toyama 930-0194, Japan
| | - Kunihiro Nishida
- Second Department of Internal Medicine, Graduate School of Medical and Pharmaceutical Sciences, University of Toyama, 2630 Sugitani, Toyama, Toyama 930-0194, Japan
| | - Yoshiaki Yamaguchi
- Second Department of Internal Medicine, Graduate School of Medical and Pharmaceutical Sciences, University of Toyama, 2630 Sugitani, Toyama, Toyama 930-0194, Japan
| | - Fukiko Ichida
- Department of Pediatrics, Graduate School of Medical and Pharmaceutical Sciences, University of Toyama, 2630 Sugitani, Toyama, Toyama 930-0194, Japan
| | - Kenkichi Fukurotani
- Laboratory for Neural Information Technology, Graduate School of Sciences and Engineering, University of Toyama, 3190 Gofuku, Toyama, Toyama 930-8555, Japan
| | - Hiroshi Inoue
- Second Department of Internal Medicine, Graduate School of Medical and Pharmaceutical Sciences, University of Toyama, 2630 Sugitani, Toyama, Toyama 930-0194, Japan
| | - Naoki Nishida
- Department of Legal Medicine, Graduate School of Medical and Pharmaceutical Sciences, University of Toyama, 2630 Sugitani, Toyama, Toyama 930-0194, Japan.
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Frolov RV, Singh S. Celecoxib and ion channels: a story of unexpected discoveries. Eur J Pharmacol 2014; 730:61-71. [PMID: 24630832 DOI: 10.1016/j.ejphar.2014.02.032] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2013] [Revised: 01/28/2014] [Accepted: 02/18/2014] [Indexed: 10/25/2022]
Abstract
Celecoxib (Celebrex), a highly popular selective inhibitor of cyclooxygenase-2, can modulate ion channels and alter functioning of neurons and myocytes at clinically relevant concentrations independently of cyclooxygenase inhibition. In experimental systems varying from Drosophila to primary mammalian and human cell lines, celecoxib inhibits many voltage-activated Na(+), Ca(2+), and K(+) channels, including NaV1.5, L- and T-type Ca(2+) channels, KV1.5, KV2.1, KV4.3, KV7.1, KV11.1 (hERG), while stimulating other K(+) channels-KV7.2-5 and, possibly, KV11.1 (hERG) channels under certain conditions. In this review, we summarize the information currently available on the effects of celecoxib on ion channels, examine mechanistic aspects of drug action and the concomitant changes at the cellular and organ levels, and discuss these findings in the therapeutic context.
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Affiliation(s)
- Roman V Frolov
- Department of Physical Sciences, Division of Biophysics, University of Oulu, PO Box 3000, 90014 Oulun Yliopisto, Finland.
| | - Satpal Singh
- Department of Pharmacology and Toxicology, State University of New York at Buffalo, Buffalo, NY 14214, USA
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Christiansen M, Hedley PL, Theilade J, Stoevring B, Leren TP, Eschen O, Sørensen KM, Tybjærg-Hansen A, Ousager LB, Pedersen LN, Frikke-Schmidt R, Aidt FH, Hansen MG, Hansen J, Bloch Thomsen PE, Toft E, Henriksen FL, Bundgaard H, Jensen HK, Kanters JK. Mutations in Danish patients with long QT syndrome and the identification of a large founder family with p.F29L in KCNH2. BMC MEDICAL GENETICS 2014; 15:31. [PMID: 24606995 PMCID: PMC4007532 DOI: 10.1186/1471-2350-15-31] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/04/2013] [Accepted: 02/18/2014] [Indexed: 01/08/2023]
Abstract
Background Long QT syndrome (LQTS) is a cardiac ion channelopathy which presents clinically with palpitations, syncope or sudden death. More than 700 LQTS-causing mutations have been identified in 13 genes, all of which encode proteins involved in the execution of the cardiac action potential. The most frequently affected genes, covering > 90% of cases, are KCNQ1, KCNH2 and SCN5A. Methods We describe 64 different mutations in 70 unrelated Danish families using a routine five-gene screen, comprising KCNQ1, KCNH2 and SCN5A as well as KCNE1 and KCNE2. Results Twenty-two mutations were found in KCNQ1, 28 in KCNH2, 9 in SCN5A, 3 in KCNE1 and 2 in KCNE2. Twenty-six of these have only been described in the Danish population and 18 are novel. One double heterozygote (1.4% of families) was found. A founder mutation, p.F29L in KCNH2, was identified in 5 “unrelated” families. Disease association, in 31.2% of cases, was based on the type of mutation identified (nonsense, insertion/deletion, frameshift or splice-site). Functional data was available for 22.7% of the missense mutations. None of the mutations were found in 364 Danish alleles and only three, all functionally characterised, were recorded in the Exome Variation Server, albeit at a frequency of < 1:1000. Conclusion The genetic etiology of LQTS in Denmark is similar to that found in other populations. A large founder family with p.F29L in KCNH2 was identified. In 48.4% of the mutations disease causation was based on mutation type or functional analysis.
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Affiliation(s)
- Michael Christiansen
- Department of Clinical Biochemistry, Immunology and Genetics, Statens Serum Institut, Ørestads Boulevard 5, 2300S, Copenhagen, Denmark.
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Bhuiyan ZA, Al-Shahrani S, Al-Aama J, Wilde AAM, Momenah TS. Congenital Long QT Syndrome: An Update and Present Perspective in Saudi Arabia. Front Pediatr 2013; 1:39. [PMID: 24400285 PMCID: PMC3864249 DOI: 10.3389/fped.2013.00039] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/15/2013] [Accepted: 11/05/2013] [Indexed: 12/14/2022] Open
Abstract
Primary cardiac arrhythmias are often caused by defects, predominantly in the genes responsible for generation of cardiac electrical potential, i.e., cardiac rhythm generation. Due to the variability in underlying genetic defects, type, and location of the mutations and putative modifiers, clinical phenotypes could be moderate to severe, even absent in many individuals. Clinical presentation and severity could be quite variable, syncope, or sudden cardiac death could also be the first and the only manifestation in a patient who had previously no symptoms at all. Despite usual familial occurrence of such cardiac arrhythmias, disease causal genetic defects could also be de novo in significant number of patients. Long QT syndrome (LQTS) is the most eloquently investigated primary cardiac rhythm disorder. A genetic defect can be identified in ∼70% of definitive LQTS patients, followed by Catecholaminergic Polymorphic Ventricular Tachycardia (CPVT) and Brugada syndrome (BrS), where a genetic defect is found in <40% cases. In addition to these widely investigated hereditary arrhythmia syndromes, there remain many other relatively less common arrhythmia syndromes, where researchers also have unraveled the genetic etiology, e.g., short QT syndrome (SQTS), sick sinus syndrome (SSS), cardiac conduction defect (CCD), idiopathic ventricular fibrillation (IVF), early repolarization syndrome (ERS). There exist also various other ill-defined primary cardiac rhythm disorders with strong genetic and familial predisposition. In the present review we will focus on the genetic basis of LQTS and its clinical management. We will also discuss the presently available genetic insight in this context from Saudi Arabia.
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Affiliation(s)
- Zahurul A. Bhuiyan
- Laboratoire de Génétique Moléculaire, Service de Génétique Médicale, Centre Hospitalier Universitaire Vaudois, Lausanne, Switzerland
| | - Safar Al-Shahrani
- Department of Pediatrics, Faculty of Medicine, King Khalid University, Abha, Saudi Arabia
| | - Jumana Al-Aama
- Princess Al Jawhara Albrahim Center of Excellence in Research of Hereditary Disorders, Jeddah, Saudi Arabia
- Department of Genetic Medicine, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Arthur A. M. Wilde
- Princess Al Jawhara Albrahim Center of Excellence in Research of Hereditary Disorders, Jeddah, Saudi Arabia
- Department of Cardiology, Academic Medical Center, University of Amsterdam, Amsterdam, Netherlands
| | - Tarek S. Momenah
- Department of Pediatric Cardiology, King Fahad Medical City, Riyadh, Saudi Arabia
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D'Argenio V, Frisso G, Precone V, Boccia A, Fienga A, Pacileo G, Limongelli G, Paolella G, Calabrò R, Salvatore F. DNA sequence capture and next-generation sequencing for the molecular diagnosis of genetic cardiomyopathies. J Mol Diagn 2013; 16:32-44. [PMID: 24183960 DOI: 10.1016/j.jmoldx.2013.07.008] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2012] [Revised: 07/03/2013] [Accepted: 07/30/2013] [Indexed: 12/15/2022] Open
Abstract
Hypertrophic cardiomyopathy is a relatively frequent disease with a prevalence of 0.2% worldwide and a remarkable genetic heterogeneity, with more than 30 causative genes reported to date. Current PCR-based strategies are inadequate for genomic investigations involving many candidate genes. Here, we report a next-generation sequencing procedure associated with DNA sequence capture that is able to sequence 202 cardiomyopathy-related genes simultaneously. We developed a complementary data analysis pipeline to select and prioritize genetic variants. The overall procedure can screen a large number of target genes simultaneously, thereby potentially revealing new disease-causing and modifier genes. By using this procedure, we analyzed hypertrophic cardiomyopathy patients in a shorter time and at a lower cost than with current procedures. The specificity of the next-generation sequencing-based procedure is at least as good as other techniques routinely used for mutation searching, and the sensitivity is much better. Analysis of the results showed some novel variants potentially involved in the pathogenesis of hypertrophic cardiomyopathy: a missense mutation in MYH7 and a nonsense variant in INS-IGF2 (patient 1), a splicing variant in MYBPC3 and an indel/frameshift variant in KCNQ1 (patient 2), and two concomitant variations in CACNA1C (patient 3). Sequencing of DNA from the three patients within a pool allowed detection of most variants identified in each individual patient, indicating that this approach is a feasible and cost-effective procedure.
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Affiliation(s)
- Valeria D'Argenio
- CEINGE-Biotecnologie Avanzate, Naples, Italy; Department of Molecular Medicine and Medical Biotechnologies, University of Naples Federico II, Naples, Italy
| | - Giulia Frisso
- CEINGE-Biotecnologie Avanzate, Naples, Italy; Department of Molecular Medicine and Medical Biotechnologies, University of Naples Federico II, Naples, Italy
| | - Vincenza Precone
- CEINGE-Biotecnologie Avanzate, Naples, Italy; Department of Molecular Medicine and Medical Biotechnologies, University of Naples Federico II, Naples, Italy
| | | | - Antonella Fienga
- Department of Molecular Medicine and Medical Biotechnologies, University of Naples Federico II, Naples, Italy
| | - Giuseppe Pacileo
- Cardiomyopathy and Inherited Heart Disease Clinic, UOC Cardiology, Second University of Naples, Naples, Italy
| | - Giuseppe Limongelli
- Cardiomyopathy and Inherited Heart Disease Clinic, UOC Cardiology, Second University of Naples, Naples, Italy
| | - Giovanni Paolella
- CEINGE-Biotecnologie Avanzate, Naples, Italy; Department of Molecular Medicine and Medical Biotechnologies, University of Naples Federico II, Naples, Italy
| | - Raffaele Calabrò
- Cardiomyopathy and Inherited Heart Disease Clinic, UOC Cardiology, Second University of Naples, Naples, Italy
| | - Francesco Salvatore
- CEINGE-Biotecnologie Avanzate, Naples, Italy; IRCCS-Fondazione SDN, Naples, Italy.
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Cuneo BF, Etheridge SP, Horigome H, Sallee D, Moon-Grady A, Weng HY, Ackerman MJ, Benson DW. Arrhythmia phenotype during fetal life suggests long-QT syndrome genotype: risk stratification of perinatal long-QT syndrome. Circ Arrhythm Electrophysiol 2013; 6:946-51. [PMID: 23995044 DOI: 10.1161/circep.113.000618] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
BACKGROUND Fetal arrhythmias characteristic of long QT syndrome (LQTS) include torsades de pointes (TdP) and/or 2° atrioventricular block, but sinus bradycardia, defined as fetal heart rate<3% for gestational age, is most common. We hypothesized that prenatal rhythm phenotype might predict LQTS genotype and facilitate improved risk stratification and management. METHOD AND RESULTS Records of subjects exhibiting fetal LQTS arrhythmias were reviewed. Fetal echocardiograms, neonatal ECG, and genetic testing were evaluated. We studied 43 subjects exhibiting fetal LQTS arrhythmias: TdP±2° atrioventricular block (group 1, n=7), isolated 2° atrioventricular block (group 2, n=4), and sinus bradycardia (group 3, n=32). Mutations in known LQTS genes were found in 95% of subjects tested. SCN5A mutations occurred in 71% of group 1, whereas 91% of subjects with KCNQ1 mutations were in group 3. Small numbers of subjects with KCNH2 mutations (n=4) were scattered in all 3 groups. Age at presentation did not differ among groups, and most subjects (n=42) were live-born with gestational ages of 37.5±2.8 weeks (mean±SD). However, those with TdP were typically delivered earlier. Prenatal treatment in group 1 terminated (n=2) or improved (n=4) TdP. The neonatal heart rate-corrected QT interval (mean±SE) of group 1 (664.7±24.9) was longer than neonatal heart rate-corrected QT interval in both group 2 (491.2±27.6; P=0.004) and group 3 (483.1±13.7; P<0.001). Despite medical and pacemaker therapy, postnatal cardiac arrest (n=4) or sudden death (n=1) was common among subjects with fetal/neonatal TdP. CONCLUSIONS Rhythm phenotypes of fetal LQTS have genotype-suggestive features that, along with heart rate-corrected QT interval duration, may risk stratify perinatal management.
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Affiliation(s)
- Bettina F Cuneo
- Department of Pediatrics, Rosalind Franklin School of Medicine and Science, North Chicago, IL
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Dobrzynski H, Anderson RH, Atkinson A, Borbas Z, D'Souza A, Fraser JF, Inada S, Logantha SJRJ, Monfredi O, Morris GM, Moorman AFM, Nikolaidou T, Schneider H, Szuts V, Temple IP, Yanni J, Boyett MR. Structure, function and clinical relevance of the cardiac conduction system, including the atrioventricular ring and outflow tract tissues. Pharmacol Ther 2013; 139:260-88. [PMID: 23612425 DOI: 10.1016/j.pharmthera.2013.04.010] [Citation(s) in RCA: 109] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2013] [Accepted: 03/28/2013] [Indexed: 01/01/2023]
Abstract
It is now over 100years since the discovery of the cardiac conduction system, consisting of three main parts, the sinus node, the atrioventricular node and the His-Purkinje system. The system is vital for the initiation and coordination of the heartbeat. Over the last decade, immense strides have been made in our understanding of the cardiac conduction system and these recent developments are reviewed here. It has been shown that the system has a unique embryological origin, distinct from that of the working myocardium, and is more extensive than originally thought with additional structures: atrioventricular rings, a third node (so called retroaortic node) and pulmonary and aortic sleeves. It has been shown that the expression of ion channels, intracellular Ca(2+)-handling proteins and gap junction channels in the system is specialised (different from that in the ordinary working myocardium), but appropriate to explain the functioning of the system, although there is continued debate concerning the ionic basis of pacemaking. We are beginning to understand the mechanisms (fibrosis and remodelling of ion channels and related proteins) responsible for dysfunction of the system (bradycardia, heart block and bundle branch block) associated with atrial fibrillation and heart failure and even athletic training. Equally, we are beginning to appreciate how naturally occurring mutations in ion channels cause congenital cardiac conduction system dysfunction. Finally, current therapies, the status of a new therapeutic strategy (use of a specific heart rate lowering drug) and a potential new therapeutic strategy (biopacemaking) are reviewed.
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Frolov RV, Bagati A, Casino B, Singh S. Potassium channels in Drosophila: historical breakthroughs, significance, and perspectives. J Neurogenet 2013. [PMID: 23181728 DOI: 10.3109/01677063.2012.744990] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Drosophila has enabled important breakthroughs in K(+) channel research, including identification and fi rst cloning of a voltage-activated K(+) channel, Shaker, a founding member of the K(V)1 family. Drosophila has also helped in discovering other K(+) channels, such as Shab, Shaw, Shal, Eag, Sei, Elk, and also Slo, a Ca(2+) - and voltage-dependent K(+) channel. These findings have contributed significantly to our understanding of ion channels and their role in physiology. Drosophila continues to play an important role in ion channel studies, benefiting from an unparalleled arsenal of genetic tools and availability of tens of thousands of genetically modified strains. These tools allow deletion, expression, or misexpression of almost any gene in question with temporal and spatial control. The combination of these tools and resources with the use of forward genetic approach in Drosophila further enhances its strength as a model system. There are many areas in which Drosophila can further help our understanding of ion channels and their function. These include signaling pathways involved in regulating and modulating ion channels, basic information on channels and currents where very little is currently known, and the role of ion channels in physiology and pathology.
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Affiliation(s)
- Roman V Frolov
- Department of Pharmacology and Toxicology, State University of New York at Buffalo, Buffalo, New York 14214-3000, USA
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Mitchell JL, Cuneo BF, Etheridge SP, Horigome H, Weng HY, Benson DW. Fetal Heart Rate Predictors of Long QT Syndrome. Circulation 2012; 126:2688-95. [DOI: 10.1161/circulationaha.112.114132] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Background—
Fetal long QT syndrome (LQTS) is associated with complex arrhythmias including torsades de pointes and 2° atrioventricular block. Sinus bradycardia has also been associated with fetal LQTS, but little is known of this rhythm manifestation. Our purpose was to characterize the fetal heart rate (FHR)/gestational age (GA) profile of fetal LQTS.
Methods and Results—
We ascertained fetal LQTS subjects by family history (Group 1) or fetal arrhythmia referral (Group 2). We compared FHR in LQTS subjects versus normal fetuses. To identify FHR predictors of LQTS, we calculated a bradycardia index as % of LQTS FHR recordings either ≤110 beats per minute (obstetric standard) or ≤3
rd
percentile for GA. Among 42 LQTS subjects, 26 were in Group 1 and 16 in Group 2. There were 536 normal fetuses. The bradycardia index was only 15% for FHR ≤110 beats per minute, but 66% for FHR ≤3rd percentile for GA. Ten fetuses with complex arrhythmias also had severe and sustained sinus bradycardia throughout gestation. Identifying a fetal proband in Group 2 resulted in LQTS diagnosis in 9 unsuspected members of 6 families.
Conclusions—
FHR varies by GA in both normal and LQTS fetuses. Postnatal evaluation of neonates with FHR ≤3
rd
percentile for GA may improve ascertainment of LQTS in fetuses, neonates, and undiagnosed family members.
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Affiliation(s)
- Jason L. Mitchell
- From the Heart Institute for Children, Oak Lawn, IL (J.L.M., B.F.C.); Primary Children's Medical Center, The University of Utah, Salt Lake City (S.P.E., H.-Y.W.); the Department of Pediatrics, University of Tskuba, Tskuba, Ibaraki, Japan (H.H.); and Cincinnati Children's Hospital Medical Center, The University of Cincinnati Medical School, Cincinnati, OH (D.W.B.)
| | - Bettina F. Cuneo
- From the Heart Institute for Children, Oak Lawn, IL (J.L.M., B.F.C.); Primary Children's Medical Center, The University of Utah, Salt Lake City (S.P.E., H.-Y.W.); the Department of Pediatrics, University of Tskuba, Tskuba, Ibaraki, Japan (H.H.); and Cincinnati Children's Hospital Medical Center, The University of Cincinnati Medical School, Cincinnati, OH (D.W.B.)
| | - Susan P. Etheridge
- From the Heart Institute for Children, Oak Lawn, IL (J.L.M., B.F.C.); Primary Children's Medical Center, The University of Utah, Salt Lake City (S.P.E., H.-Y.W.); the Department of Pediatrics, University of Tskuba, Tskuba, Ibaraki, Japan (H.H.); and Cincinnati Children's Hospital Medical Center, The University of Cincinnati Medical School, Cincinnati, OH (D.W.B.)
| | - Hitoshi Horigome
- From the Heart Institute for Children, Oak Lawn, IL (J.L.M., B.F.C.); Primary Children's Medical Center, The University of Utah, Salt Lake City (S.P.E., H.-Y.W.); the Department of Pediatrics, University of Tskuba, Tskuba, Ibaraki, Japan (H.H.); and Cincinnati Children's Hospital Medical Center, The University of Cincinnati Medical School, Cincinnati, OH (D.W.B.)
| | - Hsin-Yi Weng
- From the Heart Institute for Children, Oak Lawn, IL (J.L.M., B.F.C.); Primary Children's Medical Center, The University of Utah, Salt Lake City (S.P.E., H.-Y.W.); the Department of Pediatrics, University of Tskuba, Tskuba, Ibaraki, Japan (H.H.); and Cincinnati Children's Hospital Medical Center, The University of Cincinnati Medical School, Cincinnati, OH (D.W.B.)
| | - D. Woodrow Benson
- From the Heart Institute for Children, Oak Lawn, IL (J.L.M., B.F.C.); Primary Children's Medical Center, The University of Utah, Salt Lake City (S.P.E., H.-Y.W.); the Department of Pediatrics, University of Tskuba, Tskuba, Ibaraki, Japan (H.H.); and Cincinnati Children's Hospital Medical Center, The University of Cincinnati Medical School, Cincinnati, OH (D.W.B.)
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Aidery P, Kisselbach J, Schweizer PA, Becker R, Katus HA, Thomas D. Impaired ion channel function related to a common KCNQ1 mutation — Implications for risk stratification in long QT syndrome 1. Gene 2012; 511:26-33. [DOI: 10.1016/j.gene.2012.09.041] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2012] [Revised: 09/05/2012] [Accepted: 09/11/2012] [Indexed: 11/28/2022]
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Jalal Z, Bordachar P, Labrousse L, Mondoly P, Ritter P, Thambo JB. Stimulation cardiaque en pédiatrie : indications, stratégies d’implantation, évolution, techniques d’avenir. ARCHIVES OF CARDIOVASCULAR DISEASES SUPPLEMENTS 2012. [DOI: 10.1016/s1878-6480(12)70825-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Jurkat-Rott K, Groome J, Lehmann-Horn F. Pathophysiological role of omega pore current in channelopathies. Front Pharmacol 2012; 3:112. [PMID: 22701429 PMCID: PMC3372090 DOI: 10.3389/fphar.2012.00112] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2012] [Accepted: 05/23/2012] [Indexed: 12/12/2022] Open
Abstract
In voltage-gated cation channels, a recurrent pattern for mutations is the neutralization of positively charged residues in the voltage-sensing S4 transmembrane segments. These mutations cause dominant ion channelopathies affecting many tissues such as brain, heart, and skeletal muscle. Recent studies suggest that the pathogenesis of associated phenotypes is not limited to alterations in the gating of the ion-conducting alpha pore. Instead, aberrant so-called omega currents, facilitated by the movement of mutated S4 segments, also appear to contribute to symptoms. Surprisingly, these omega currents conduct cations with varying ion selectivity and are activated in either a hyperpolarized or depolarized voltage range. This review gives an overview of voltage sensor channelopathies in general and focuses on pathogenesis of skeletal muscle S4 disorders for which current knowledge is most advanced.
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Es-Salah-Lamoureux Z, Xiong PY, Goodchild SJ, Ahern CA, Fedida D. Blockade of permeation by potassium but normal gating of the G628S nonconducting hERG channel mutant. Biophys J 2011; 101:662-70. [PMID: 21806934 DOI: 10.1016/j.bpj.2011.06.028] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2011] [Revised: 06/10/2011] [Accepted: 06/17/2011] [Indexed: 12/21/2022] Open
Abstract
G628S is a mutation in the signature sequence that forms the selectivity filter of the human ether-a-go-go-related gene (hERG) channel (GFG) and is associated with long-QT2 syndrome. G628S channels are known to have a dominant-negative effect on hERG currents, and the mutant is therefore thought to be nonfunctional. This study aims to assess the physiological mechanism that prevents the surface-expressing G628S channels from conducting ions. We used voltage-clamp fluorimetry along with two-microelectrode voltage clamping in Xenopus oocytes to confirm that the channels express well at the surface, and to show that they are actually functional, with activation kinetics comparable to that of wild-type, and that the mutation leads to a reduced selectivity to potassium. Although ionic currents are not detected in physiological solutions, removing extracellular K(+) results in the appearance of an inward Na(+)-dependent current. Using whole-cell patch clamp in mammalian transfected cells, we demonstrate that the G628S channels conduct Na(+), but that this can be blocked by both intracellular and higher-than-physiological extracellular K(+). Using solutions devoid of K(+) allows the appearance of nA-sized Na(+) currents with activation and inactivation gating analogous to wild-type channels. The G628S channels are functionally conducting but are normally blocked by intracellular K(+).
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Affiliation(s)
- Zeineb Es-Salah-Lamoureux
- Department of Anesthesiology, Pharmacology, and Therapeutics, University of British Columbia, Vancouver, British Columbia, Canada
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Frolov RV, Ignatova II, Singh S. Inhibition of HERG potassium channels by celecoxib and its mechanism. PLoS One 2011; 6:e26344. [PMID: 22039467 PMCID: PMC3200315 DOI: 10.1371/journal.pone.0026344] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2011] [Accepted: 09/25/2011] [Indexed: 02/02/2023] Open
Abstract
BACKGROUND Celecoxib (Celebrex), a widely prescribed selective inhibitor of cyclooxygenase-2, can modulate ion channels independently of cyclooxygenase inhibition. Clinically relevant concentrations of celecoxib can affect ionic currents and alter functioning of neurons and myocytes. In particular, inhibition of Kv2.1 channels by celecoxib leads to arrhythmic beating of Drosophila heart and of rat heart cells in culture. However, the spectrum of ion channels involved in human cardiac excitability differs from that in animal models, including mammalian models, making it difficult to evaluate the relevance of these observations to humans. Our aim was to examine the effects of celecoxib on hERG and other human channels critically involved in regulating human cardiac rhythm, and to explore the mechanisms of any observed effect on the hERG channels. METHODS AND RESULTS Celecoxib inhibited the hERG, SCN5A, KCNQ1 and KCNQ1/MinK channels expressed in HEK-293 cells with IC(50)s of 6.0 µM, 7.5 µM, 3.5 µM and 3.7 µM respectively, and the KCND3/KChiP2 channels expressed in CHO cells with an IC(50) of 10.6 µM. Analysis of celecoxib's effects on hERG channels suggested gating modification as the mechanism of drug action. CONCLUSIONS The above channels play a significant role in drug-induced long QT syndrome (LQTS) and short QT syndrome (SQTS). Regulatory guidelines require that all new drugs under development be tested for effects on the hERG channel prior to first administration in humans. Our observations raise the question of celecoxib's potential to induce cardiac arrhythmias or other channel related adverse effects, and make a case for examining such possibilities.
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Affiliation(s)
- Roman V. Frolov
- Department of Pharmacology and Toxicology, State University of New York, Buffalo, New York, United States of America
- Division of Biophysics, Department of Physical Sciences, University of Oulu, Oulun Yliopisto, Finland
| | - Irina I. Ignatova
- Department of Pharmacology and Toxicology, State University of New York, Buffalo, New York, United States of America
- Division of Biophysics, Department of Physical Sciences, University of Oulu, Oulun Yliopisto, Finland
| | - Satpal Singh
- Department of Pharmacology and Toxicology, State University of New York, Buffalo, New York, United States of America
- * E-mail:
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Baruteau AE, Fouchard S, Behaghel A, Mabo P, Villain E, Thambo JB, Marçon F, Gournay V, Rouault F, Chantepie A, Guillaumont S, Godart F, Bonnet C, Fraisse A, Schleich JM, Lusson JR, Dulac Y, Leclercq C, Daubert JC, Schott JJ, Le Marec H, Probst V. Characteristics and long-term outcome of non-immune isolated atrioventricular block diagnosed in utero or early childhood: a multicentre study. Eur Heart J 2011; 33:622-9. [PMID: 21920962 DOI: 10.1093/eurheartj/ehr347] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
AIMS The natural history of congenital or childhood non-immune, isolated atrioventricular (AV) block is poorly defined. METHODS AND RESULTS We retrospectively studied 141 children with isolated, non-immune AV block diagnosed in utero, or up to 15 years of age, at 13 French medical centres, between 1980 and 2009. Patients with structural heart disease or maternal antibodies were excluded. Atrioventricular block was asymptomatic in 119 (84.4%) and complete in 100 (70.9%) patients. There was progression to complete AV block in 29/41 (70.7%) patients with incomplete AV block over 2.8 ± 3.4 years (1-155 months), but all patients with incomplete AV block may not have been included in the study. Narrow QRS complex was present in 18 of 26 patients (69.2%) with congenital, and 106 of 115 (92.2%) with childhood AV block. Pacemakers were implanted in 112 children (79.4%), during the first year of life in 18 (16.1%) and before 10 years of age in 90 (80.4%). The mean interval between diagnosis of AV block and pacemaker implants was 2.6 ± 3.9 years (0-300 months). The pacing indication was prophylactic in 70 children (62.5%). During a mean follow-up of 11.6 ± 6.7 years (1-32 years), no patient died or developed dilated cardiomyopathy (DCM). The long-term follow-up was uncomplicated in 127 children (90.1%). CONCLUSION In this large multicentre study, the long-term outcome of congenital or childhood non-immune, isolated AV block was favourable, regardless of the patient's age at the time of diagnosis. No patient died or developed DCM, and pacemaker-related complications were few.
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Prevalence of HCM and long QT syndrome mutations in young sudden cardiac death-related cases. Int J Legal Med 2011; 125:565-72. [PMID: 21499742 DOI: 10.1007/s00414-011-0572-7] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2010] [Accepted: 04/01/2011] [Indexed: 01/08/2023]
Abstract
Cardiomyopathies and channelopathies are major causes of sudden cardiac death. The genetic study of these diseases is difficult because of their heterogenic nature not only in their genetic traits but also in their phenotypic expression. The purpose of the present study is the analysis of a wide spectrum of previously known genetic mutations in key genes related to hypertrophic cardiomyopathy (HCM), long QT syndrome (LQTS), and Brugada syndrome (BrS) development. The samples studied include cases of sudden cardiac death (SCD) in young adults and their relatives in order to identify the real impact of genetic screening of SCD in forensic cases. Genetic screening of described variation in 16 genes implicated in the development of HCM and three more genes implicated in LQTS and BrS was performed by using MassARRAY technology. In addition, direct sequencing of the two most prevalent genes implicated in the development of SQTL type 1 and 2 was also carried out. Genetic screening allowed us to unmask four possibly pathogenic mutation carriers in the 49 SCD cases considered; carriers of mutation represent 9% (2/23) of the probands with structural anomalies found after autopsy and 7% (1/14) of the probands with structurally normal hearts after in depth autopsy protocol. One mutation was found among 12 of the recovered SCD cases considered. In people with direct family history of sudden cardiac death, but not themselves, 11 additional mutation carriers were found. Three different mutations were found in six of the 19 LQTS patients, representing three families and two different mutations were found among six patients with previous syncope. Genetic analysis in sudden cardiac death cases could help to elucidate the cause of death, but it also can help in the prevention of future deaths in families at risk. The study presented here shows the importance and relevance of genetic screening in patients with signs of cardiac hypertrophy and in family cases with more than one relative affected.
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Sarubbi B, Frisso G, Romeo E, Evangelista E, Cordella A, D'Alto M, Santarpia G, Russo MG, Salvatore F, Calabrò R. Efficacy of pharmacological treatment and genetic characterization in early diagnosed patients affected by long QT syndrome with impaired AV conduction. Int J Cardiol 2011; 149:109-13. [PMID: 21481956 DOI: 10.1016/j.ijcard.2010.12.099] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/24/2010] [Accepted: 12/29/2010] [Indexed: 10/18/2022]
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Furushima H, Chinushi M, Sato A, Aizawa Y, Kikuchi A, Takakuwa K, Tanaka K. Fetal atrioventricular block and postpartum augmentative QT prolongation in a patient with long-QT syndrome with KCNQ1 mutation. J Cardiovasc Electrophysiol 2011; 21:1170-3. [PMID: 20487114 DOI: 10.1111/j.1540-8167.2010.01758.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The case of a 32-year-old pregnant woman, who had had several syncopal episodes during swimming and running at 9 and 10 years of age and whose fetus had 2:1 AV block, is presented. The mother and baby had the same heterozygous single nucleotide substitution in KCNQ1 at T587M. After 27 weeks of gestation, the fetal 2:1 AV block disappeared, and 1:1 AV conduction resumed, with a fetal heart rate of 110-120 beats/min. The maternal electrocardiogram revealed a normal QTc interval (433 ms) without ST-T abnormalities at gestational week 23, but the QTc was 490 and 531 ms at 1 and 2 months postpartum, with biphasic T waves in leads V2 and V3. This case is the first report of fetal 2:1 AV block with KCNQ1 mutation (T587M) and unmasked maternal QT prolongation in the postpartum period.
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Affiliation(s)
- Hiroshi Furushima
- First Department of Internal Medicine, Niigata University School of Medicine, Asahimachi-dori, Niigata, Japan.
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