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Askarinejad A, Esmaeili S, Dalili M, Biglari A, Kohansal E, Maleki M, Kalayinia S. Catecholaminergic polymorphic ventricular tachycardia (and seizure) caused by a novel homozygous likely pathogenic variant in CASQ2 gene. Gene 2024; 895:148012. [PMID: 37995796 DOI: 10.1016/j.gene.2023.148012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2023] [Accepted: 11/15/2023] [Indexed: 11/25/2023]
Abstract
BACKGROUND Although structural heart disease is frequently present among patients who experience sudden cardiac death (SCD), inherited arrhythmia syndromes can also play an important role in the occurrence of SCD. CPVT2, which is the second-most prevalent form of CPVT, arises from an abnormality in the CASQ2 gene. OBJECTIVE We represent a novel CASQ2 variant that causes CPVT2 and conduct a comprehensive review on this topic. METHODS The proband underwent Whole-exome sequencing (WES) in order to ascertain the etiology of CPVT. Subsequently, the process of segregating the available family members was carried out through the utilization of PCR and Sanger Sequencing. We searched the google scholar and PubMed/Medline for studies reporting CASQ2 variants, published up to May 10,2023. We used the following mesh term "Calsequestrin" and using free-text method with terms including "CASQ2","CASQ2 variants", and "CASQ2 mutation". RESULTS The CASQ2 gene was found to contain an autosomal recessive nonsense variant c.268_269insTA:p.Gly90ValfsTer4, which was identified by WES. This variant was determined to be the most probable cause of CPVT in the pedigree under investigation. CONCLUSION CASQ2 variants play an important role in pathogenesis of CPVT2. Notabely, based on results of our study and other findings in the literature the variant in this gene may cause an neurological signs in the patients with CPVT2. Further studies are needed for more details about the role of this gene in CPVT evaluation, diagnosis, and gene therapy.
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Affiliation(s)
- Amir Askarinejad
- Rajaie Cardiovascular Medical and Research Center, Iran University of Medical Sciences, Tehran, Iran University of Medical Sciences, Tehran, Iran
| | - Shiva Esmaeili
- Rajaie Cardiovascular Medical and Research Center, Iran University of Medical Sciences, Tehran, Iran University of Medical Sciences, Tehran, Iran
| | - Mohamad Dalili
- Rajaie Cardiovascular Medical and Research Center, Iran University of Medical Sciences, Tehran, Iran University of Medical Sciences, Tehran, Iran
| | - Alireza Biglari
- Rajaie Cardiovascular Medical and Research Center, Iran University of Medical Sciences, Tehran, Iran University of Medical Sciences, Tehran, Iran
| | - Erfan Kohansal
- Rajaie Cardiovascular Medical and Research Center, Iran University of Medical Sciences, Tehran, Iran University of Medical Sciences, Tehran, Iran
| | - Majid Maleki
- Cardiogenetic Research Center, Rajaie Cardiovascular Medical and Research Center, Iran University of Medical Sciences, Tehran, Iran
| | - Samira Kalayinia
- Cardiogenetic Research Center, Rajaie Cardiovascular Medical and Research Center, Iran University of Medical Sciences, Tehran, Iran.
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Bjelic M, Goldenberg I, Younis A, Chen AY, Huang DT, Yoruk A, Aktas MK, Rosero S, Cutter K, McNitt S, Sotoodehnia N, Kudenchuk PJ, Rea TD, Arking DE, Zareba W, Ackerman MJ, Goldenberg I. Risk Prediction in Male Adolescents With Congenital Long QT Syndrome: Implications for Sex-Specific Risk Stratification in Potassium Channel-Mediated Long QT Syndrome. J Am Heart Assoc 2024; 13:e028902. [PMID: 38240206 DOI: 10.1161/jaha.122.028902] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/18/2022] [Accepted: 07/06/2023] [Indexed: 02/07/2024]
Abstract
BACKGROUND Sex-specific risk management may improve outcomes in congenital long QT syndrome (LQTS). We recently developed a prediction score for cardiac events (CEs) and life-threatening events (LTEs) in postadolescent women with LQTS. In the present study, we aimed to develop personalized risk estimates for the burden of CEs and LTEs in male adolescents with potassium channel-mediated LQTS. METHODS AND RESULTS The prognostic model was derived from the LQTS Registry headquartered in Rochester, NY, comprising 611 LQT1 or LQT2 male adolescents from age 10 through 20 years, using the following variables: genotype/mutation location, QTc-specific thresholds, history of syncope, and β-blocker therapy. Anderson-Gill modeling was performed for the end point of CE burden (total number of syncope, aborted cardiac arrest, and appropriate defibrillator shocks). The applicability of the CE prediction model was tested for the end point of the first LTE (excluding syncope and adding sudden cardiac death) using Cox modeling. A total of 270 CEs occurred during follow-up. The genotype-phenotype risk prediction model identified low-, intermediate-, and high-risk groups, comprising 74%, 14%, and 12% of the study population, respectively. Compared with the low-risk group, high-risk male subjects experienced a pronounced 5.2-fold increased risk of recurrent CEs (P<0.001), whereas intermediate-risk patients had a 2.1-fold (P=0.004) increased risk . At age 20 years, the low-, intermediate-, and high-risk adolescent male patients had on average 0.3, 0.6, and 1.4 CEs per person, respectively. Corresponding 10-year adjusted probabilities for a first LTE were 2%, 6%, and 8%. CONCLUSIONS Personalized genotype-phenotype risk estimates can be used to guide sex-specific management in male adolescents with potassium channel-mediated LQTS.
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Affiliation(s)
- Milica Bjelic
- Clinical Cardiovascular Research Center, Division of Cardiology University of Rochester Medical Center Rochester NY USA
- Department of Anesthesiology St. Elizabeth's Medical Center Boston University School of Medicine Boston MA USA
| | - Ido Goldenberg
- Clinical Cardiovascular Research Center, Division of Cardiology University of Rochester Medical Center Rochester NY USA
- Department of Medicine, Rochester Regional Health Rochester NY USA
| | - Arwa Younis
- Clinical Cardiovascular Research Center, Division of Cardiology University of Rochester Medical Center Rochester NY USA
- Department of Cardiovascular Medicine Cleveland Clinic Cleveland OH USA
| | - Anita Y Chen
- Department of Biostatistics and Computational Biology University of Rochester Medical Center Rochester NY USA
| | - David T Huang
- Department of Medicine, Division of Cardiology University of Rochester Medical Center Rochester NY USA
| | - Ayhan Yoruk
- Division of Cardiology The University of California, San Francisco Medical Center San Francisco CA USA
| | - Mehmet K Aktas
- Department of Medicine, Division of Cardiology University of Rochester Medical Center Rochester NY USA
| | - Spencer Rosero
- Department of Medicine, Division of Cardiology University of Rochester Medical Center Rochester NY USA
| | - Kristina Cutter
- Clinical Cardiovascular Research Center, Division of Cardiology University of Rochester Medical Center Rochester NY USA
| | - Scott McNitt
- Clinical Cardiovascular Research Center, Division of Cardiology University of Rochester Medical Center Rochester NY USA
| | - Nona Sotoodehnia
- Department of Medicine, Division of Cardiology University of Washington Seattle WA USA
| | | | - Thomas D Rea
- Department of Medicine University of Washington Seattle WA USA
| | - Dan E Arking
- The McKusick-Nathans Institute, Department of Genetic Medicine John Hopkins University School of Medicine Baltimore MD USA
| | - Wojciech Zareba
- Clinical Cardiovascular Research Center, Division of Cardiology University of Rochester Medical Center Rochester NY USA
| | - Michael J Ackerman
- Departments of Cardiovascular Medicine, Pediatric and Adolescent Medicine, and Molecular Pharmacology & Experimental Therapeutics, Divisions of Heart Rhythm Services and Pediatric Cardiology, Windland Smith Rice Genetic Heart Rhythm Clinic and Windland Smith Rice Sudden Death Genomics Laboratory Mayo Clinic Rochester MN USA
| | - Ilan Goldenberg
- Clinical Cardiovascular Research Center, Division of Cardiology University of Rochester Medical Center Rochester NY USA
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Vokač D, Stangler Herodež Š, Krgović D, Kokalj Vokač N. The Role of Next-Generation Sequencing in the Management of Patients with Suspected Non-Ischemic Cardiomyopathy after Syncope or Termination of Sudden Arrhythmic Death. Genes (Basel) 2024; 15:72. [PMID: 38254962 PMCID: PMC10815304 DOI: 10.3390/genes15010072] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2023] [Revised: 12/29/2023] [Accepted: 01/03/2024] [Indexed: 01/24/2024] Open
Abstract
Cardiac arrhythmias and sudden death are frequent in patients with non-ischemic cardiomyopathy and can precede heart failure or additional symptoms where malignant cardiac arrhythmias are mostly the consequence of advanced cardiomyopathy and heart failure. Finding these subgroups and making an early diagnosis could be lifesaving. In our retrospective study, we are presenting arrhythmic types of frequent cardiomyopathies where an arrhythmogenic substrate is less well defined, as in ischemic or structural heart disease. In the period of 2 years, next-generation sequencing (NGS) tests along with standard clinical tests were performed in 208 patients (67 women and 141 men; mean age, 51.2 ± 19.4 years) without ischemic or an overt structural heart disease after syncope or aborted sudden cardiac death. Genetic variants were detected in 34.4% of the study population, with a significant proportion of pathogenic variants (P) (14.4%) and variants of unknown significance (VUS) (20%). Regardless of genotype, all patients were stratified according to clinical guidelines for aggressive treatment of sudden cardiac death with an implantable cardioverter defibrillator (ICD). The P variant identified by NGS serves for an accurate diagnosis and, thus, better prevention and specific treatment of patients and their relatives. Results in our study suggest that targeted sequencing of genes associated with cardiovascular disease is an important addendum for final diagnosis, allowing the identification of a molecular genetic cause in a vast proportion of patients for a definitive diagnosis and a more specific way of treatment. VUS in this target population poses a high risk and should be considered possibly pathogenic in reanalysis.
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Affiliation(s)
- Damijan Vokač
- Department of Cardiology and Angiology, Division of Internal Medicine, University Medical Centre Maribor, 2000 Maribor, Slovenia;
| | - Špela Stangler Herodež
- Clinical Institute for Genetic Diagnostics, University Medical Centre Maribor, 2000 Maribor, Slovenia; (Š.S.H.); (D.K.)
- Medical Faculty, University of Maribor, 2000 Maribor, Slovenia
| | - Danijela Krgović
- Clinical Institute for Genetic Diagnostics, University Medical Centre Maribor, 2000 Maribor, Slovenia; (Š.S.H.); (D.K.)
- Medical Faculty, University of Maribor, 2000 Maribor, Slovenia
| | - Nadja Kokalj Vokač
- Clinical Institute for Genetic Diagnostics, University Medical Centre Maribor, 2000 Maribor, Slovenia; (Š.S.H.); (D.K.)
- Medical Faculty, University of Maribor, 2000 Maribor, Slovenia
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Sun Q, Xie Z, Wang F, Guo J, Yan X. Case report of a child with long QT syndrome type 14 caused by CALM1 gene mutation and literature review. Mol Genet Genomic Med 2024; 12:e2287. [PMID: 37905352 PMCID: PMC10767591 DOI: 10.1002/mgg3.2287] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Revised: 08/24/2023] [Accepted: 09/07/2023] [Indexed: 11/02/2023] Open
Abstract
OBJECTIVE To analyze the clinical and genetic characteristics of a patient with long QT syndrome type 14 (long QT syndrome-14, LQT14, OMIM # 616247) caused by a de novo CALM1 mutation. METHODS The clinical data of the patient were collected, next-generation sequencing technology was used to determine the exome gene sequence of the patient, and the suspected pathogenic locus was verified by Sanger sequencing. RESULTS A 5-year and 9-month-old girl was admitted to the hospital due to a syncopal episode. During the attack, the main symptoms were loss of consciousness, cyanosis of the face and lips, and weakness of limbs. The child had multiple seizures in the past, all of which occurred after emotional excitement and activity. She was diagnosed with epilepsy for more than 3 years, but the effect of antiepileptic treatment was not satisfactory. The electrocardiogram was normal in the past. A month ago, convulsions occurred again after exercise, and the electrocardiogram showed QTc 496 ms. The treadmill test showed a significant prolongation of QTc after exercise, and the genetic results suggested a new heterozygous variant of CALM1, c.395A>G; p. (Asp132Gly). Consequently, she was diagnosed with LQT14 and treated with propranolol. During a follow-up of 15 months, there were no seizures or syncope. CONCLUSIONS This patient had multiple episodes of convulsions or syncope after emotional stimulation or activity, with intermittent prolongation of the QTc on routine ECG, marked prolongation of the QTc after exercise, and T-wave alternans, which differed from the LQT14 phenotype caused by the previous CALM1 mutation.
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Affiliation(s)
- Qiqing Sun
- Department of CardiologyChildren's Hospital Affiliated to Zhengzhou University, Zhengzhou Hospital of Beijing Children's HospitalZhengzhouChina
| | - Zhenhua Xie
- Henan Key Laboratory of Pediatric Inherited and Metabolic DiseasesChildren's Hospital Affiliated to Zhengzhou University, Zhengzhou Hospital of Beijing Children's HospitalZhengzhouChina
| | - Fangjie Wang
- Department of CardiologyChildren's Hospital Affiliated to Zhengzhou University, Zhengzhou Hospital of Beijing Children's HospitalZhengzhouChina
| | - Jun Guo
- Beijing Key Laboratory for Genetics of Birth DefectsBeijing Pediatric Research Institute, MOE Key Laboratory of Major Diseases in Children, Capital Medical University, Center of Rare Diseases, National Center for Children's Health, Beijing Children's Hospital, Capital Medical UniversityBeijingChina
| | - Xiaochen Yan
- Department of CardiologyChildren's Hospital Affiliated to Zhengzhou University, Zhengzhou Hospital of Beijing Children's HospitalZhengzhouChina
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Righi D, Porco L, Di Mambro C, Gnazzo M, Baban A, Paglia S, Silvetti MS, Novelli A, Tozzi AE, Drago F. Autosomal Recessive Long QT Syndrome: Clinical Aspects and Therapy. Pediatr Cardiol 2023; 44:1736-1740. [PMID: 37597120 DOI: 10.1007/s00246-023-03266-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Accepted: 08/04/2023] [Indexed: 08/21/2023]
Abstract
The autosomal recessive (AR) form of Long QT Syndrome (LQTS) is described both associated with deafness known as Jervell and Lange-Nielsen (JLN) syndrome, and without deafness (WD). The aim of the study is to report the characteristics of AR LQTS patients and the efficacy of the therapy. Data of all children with AR LQTS referred to the Bambino Gesù Children's Hospital IRCCS from September 2012 to September 2021were included. Three (30%) patients had compound heterozygosity and 7 (70%) had homozygous variants of the KCNQ1 gene, the latter showing deafness. Four patients (40%) presented aborted sudden cardiac death (aSCD): three with previous episodes of syncope (75%), the other without previous symptoms (16.6% of asymptomatic patients). An episode of aSCD occurred in 2/3 (66.7%) of WD and heterozygous patients, while in 2/7 (28%) JLN and homozygous patients and in 2/2 patients with QTC > 600 ms. All patients were treated with Nadolol. In 5 Mexiletine was added, shortening QTc and obtaining the disappearance of the T-wave alternance (TWA) in 3/3. Episodes of aSCD seem to be more frequent in LQTS patients with compound heterozygous variants and WD than in those with JLN and homozygous variants. Episodes of aSCD also appear more frequent in children with syncope or with QTc value > 600 ms, even on beta-blocker therapy, than in patients without syncope or with Qtc < 600 ms. However, our descriptive results should be confirmed by larger studies. Moreover, Mexiletine addition reduced QTc value and eliminated TWA.
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Affiliation(s)
- Daniela Righi
- Cardiac Arrhythmias Complex Unit, Department of Pediatric Cardiology, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy.
| | - Luigina Porco
- Cardiac Arrhythmias Complex Unit, Department of Pediatric Cardiology, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy
| | - Corrado Di Mambro
- Cardiac Arrhythmias Complex Unit, Department of Pediatric Cardiology, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy
| | - Maria Gnazzo
- Laboratory of Medical Genetics, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy
| | - Anwar Baban
- Cardiac Arrhythmias Complex Unit, Department of Pediatric Cardiology, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy
| | - Simone Paglia
- Cardiac Arrhythmias Complex Unit, Department of Pediatric Cardiology, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy
| | - Massimo Stefano Silvetti
- Cardiac Arrhythmias Complex Unit, Department of Pediatric Cardiology, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy
| | - Antonio Novelli
- Laboratory of Medical Genetics, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy
| | - Alberto Eugenio Tozzi
- Predictive and Preventive Medicine Research Unit, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy
| | - Fabrizio Drago
- Cardiac Arrhythmias Complex Unit, Department of Pediatric Cardiology, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy
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d’Apolito M, Santoro F, Santacroce R, Cordisco G, Ragnatela I, D’Arienzo G, Pellegrino PL, Brunetti ND, Margaglione M. A Novel DLG1 Variant in a Family with Brugada Syndrome: Clinical Characteristics and In Silico Analysis. Genes (Basel) 2023; 14:427. [PMID: 36833354 PMCID: PMC9957379 DOI: 10.3390/genes14020427] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2023] [Revised: 01/31/2023] [Accepted: 02/05/2023] [Indexed: 02/10/2023] Open
Abstract
BACKGROUND Brugada syndrome (BrS) is an inherited primary channelopathy syndrome associated to sudden cardiac death. Overall, variants have been identified in eighteen genes encoding for ion channel subunits and seven genes for regulatory proteins. Recently, a missense variant in DLG1 has been found within a BrS phenotype-positive patient. DLG1 encodes for synapse associated protein 97 (SAP97), a protein characterized by the presence of multiple domains for protein-protein interactions including PDZ domains. In cardiomyocytes, SAP97 interacts with Nav1.5, a PDZ binding motif of SCN5A and others potassium channel subunits. AIM OF THE STUDY To characterize the phenotype of an Italian family with BrS syndrome carrying a DLG1 variant. METHODS Clinical and genetic investigations were performed. Genetic testing was performed with whole-exome sequencing (WES) using the Illumina platform. According to the standard protocol, a variant found by WES was confirmed in all members of the family by bi-directional capillary Sanger resequencing. The effect of the variant was investigated by using in silico prediction of pathogenicity. RESULTS The index case was a 74-year-old man with spontaneous type 1 BrS ECG pattern that experienced syncope and underwent ICD implantation. WES of the index case, performed assuming a dominant mode of inheritance, identified a heterozygous variant, c.1556G>A (p.R519H), in the exon 15 of the DLG1 gene. In the pedigree investigation, 6 out of 12 family members had the variant. Carriers of the gene variant all had BrS ECG type 1 drug induced and showed heterogeneous cardiac phenotypes with two patients experiencing syncope during exercise and fever, respectively. The amino acid residue #519 lies near a PDZ domain and in silico analysis suggested a causal role for the variant. Modelling of the resulting protein structure predicted that the variant disrupts an H-bond and a likelihood of being pathogenic. As a consequence, it is likely that a conformational change affects protein functionality and the modulating role on ion channels. CONCLUSIONS A DLG1 gene variant identified was associated with BrS. The variant could modify the formation of multichannel protein complexes, affecting ion channels to specific compartments in cardiomyocytes.
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Affiliation(s)
- Maria d’Apolito
- Medical Genetics, Department of Clinical and Experimental Medicine, University of Foggia, 71122 Foggia, Italy
| | - Francesco Santoro
- Department of Medical and Surgical Sciences, University of Foggia, 71122 Foggia, Italy
- Cardiology Unit, Polyclinic Hospital of Foggia, 71122 Foggia, Italy
| | - Rosa Santacroce
- Medical Genetics, Department of Clinical and Experimental Medicine, University of Foggia, 71122 Foggia, Italy
| | - Giorgia Cordisco
- Medical Genetics, Department of Clinical and Experimental Medicine, University of Foggia, 71122 Foggia, Italy
| | - Ilaria Ragnatela
- Department of Medical and Surgical Sciences, University of Foggia, 71122 Foggia, Italy
| | | | | | - Natale Daniele Brunetti
- Department of Medical and Surgical Sciences, University of Foggia, 71122 Foggia, Italy
- Cardiology Unit, Polyclinic Hospital of Foggia, 71122 Foggia, Italy
| | - Maurizio Margaglione
- Medical Genetics, Department of Clinical and Experimental Medicine, University of Foggia, 71122 Foggia, Italy
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Abstract
IMPORTANCE Reflex syncope is the major cause of transient loss of consciousness, which affects one-third of the population, but effective treatment for individuals with severe syncope is lacking. Better understanding of reflex syncope predisposition may offer new therapeutic solutions. OBJECTIVES To determine the familial risk of syncope in first-, second-, and third-degree relatives of affected individuals and to explore the role of genes and family environment in reflex syncope. DESIGN, SETTING, AND PARTICIPANTS In this national population-based family cohort study, the Swedish multigeneration register was linked to 3 Swedish nationwide registers: hospital discharge, outpatient care, and primary care registers for the period from 1997 to 2015. Sibling pairs born to Swedish parents between 1948 and 2005 were included. Linkage was also made to half-siblings and cousins. Data analysis was performed from June to October 2020. EXPOSURES Register-based syncope diagnosis among relatives: pairs of twins, siblings, half-siblings, and cousins. MAIN OUTCOMES AND MEASURES Odds ratios for syncope were calculated for relatives (twins, siblings, half-siblings, and cousins) of individuals who had syncope compared with relatives of individuals without syncope for reference. Sensitivity analysis excluding families with definite nonreflex syncope diagnosis was performed. RESULTS Among the study population of 2 694 442 participants, 1 381 453 (51.3%) were male, and the median (interquartile range) age was 32 (22-43) years. The study population consisted of 24 020 twins, 1 546 108 siblings, 264 244 half-siblings, and 1 044 546 cousins. In total, 61 861 (2.30%) unique individuals were diagnosed with syncope. Sixty-two percent (38 226) of the syncope-positive individuals were female. The odds ratio (OR) for syncope was 2.39 (95% CI, 1.61-3.53) for twins, 1.81 (95% CI, 1.71-1.91) for siblings, 1.28 (95% CI, 1.20-1.37) for half-siblings, and 1.13 (95% CI, 1.10-1.17) for cousins of individuals with syncope. The OR was highest among male twins at 5.03 (95% CI, 2.57-9.85). The proportion of syncope-positive individuals was consistently higher in women vs men, regardless of degree of relationship (twins: 346 [2.88%] vs 193 [1.61%]; siblings: 22 111 [2.92%] vs 13 419 [1.70%], half-siblings: 4148 [3.44%] vs 2425 [1.93%], cousins: 14 498 [2.87%] vs 9246 [1.72%]). Exclusion of nonreflex syncope diagnoses did not change syncope risk in affected families. CONCLUSIONS AND RELEVANCE In this Swedish national population-based study, the risk of syncope among relatives of affected individuals was associated with the relationship degree and was strongest in twins and siblings, which suggests that there are genetic components of reflex syncope. Women were more likely to experience syncope independently of family relationship. A better understanding of genetic predisposition to reflex syncope may offer new therapeutic options in severely affected individuals.
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Affiliation(s)
- Artur Fedorowski
- Department of Clinical Sciences, Lund University, Malmö, Sweden
- Department of Cardiology, Skåne University Hospital, Malmö, Sweden
| | - Mirnabi Pirouzifard
- Center for Primary Health Care Research, Lund University/Region Skåne, Malmö, Sweden
| | - Jan Sundquist
- Center for Primary Health Care Research, Lund University/Region Skåne, Malmö, Sweden
- Stanford Prevention Research Center, Stanford University School of Medicine, Palo Alto, California
| | - Kristina Sundquist
- Center for Primary Health Care Research, Lund University/Region Skåne, Malmö, Sweden
- Stanford Prevention Research Center, Stanford University School of Medicine, Palo Alto, California
| | - Richard Sutton
- Department of Cardiology, Skåne University Hospital, Malmö, Sweden
- National Heart and Lung Institute, Imperial College, Department of Cardiology, London, United Kingdom
| | - Bengt Zöller
- Center for Primary Health Care Research, Lund University/Region Skåne, Malmö, Sweden
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Das BB, Chan KC. Syncope in a Child with Pulmonary Hypertension and Positive Gene Tests for Hereditary Hemorrhagic Telangiectasia and Long QT Syndrome. Cardiovasc Hematol Agents Med Chem 2020; 18:70-76. [PMID: 31657683 DOI: 10.2174/1871525717666191028102503] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2019] [Revised: 10/17/2019] [Accepted: 10/17/2019] [Indexed: 06/10/2023]
Abstract
We present a 10-year-old boy with syncope who was found to have long-QT syndrome and severe Pulmonary Hypertension (PH) both in the absence of a secondary cause; to our knowledge, this is the first report with this unusual coexistence. His genetic tests were positive for hereditary hemorrhagic telangiectasia and Long QT Syndrome (LQTS) without any family history of PH or LQTS. We demonstrated that digital subtraction pulmonary angiography was more useful compared to CT angiogram to demonstrate pulmonary vascular changes which correlated with a noresponse to acute vasoreactivity testing during right heart catheterization. He has been stable for the last 2 years on Ambrisentan, Sildenafil, and Nadolol without recurrence of symptoms.
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Affiliation(s)
- Bibhuti B Das
- Department of Pediatric Cardiology, Baylor College of Medicine, Texas Children's Hospital, Austin Specialty Care, Austin, TX 78759, United States
| | - Kak-Chen Chan
- Joe DiMaggio Children's Hospital Heart Institute, Memorial Healthcare System, Hollywood, FL 33021, United States
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Abou Ziki MD, Seidelmann SB, Smith E, Atteya G, Jiang Y, Fernandes RG, Marieb MA, Akar JG, Mani A. Deleterious protein-altering mutations in the SCN10A voltage-gated sodium channel gene are associated with prolonged QT. Clin Genet 2018; 93:741-751. [PMID: 28407228 PMCID: PMC5640462 DOI: 10.1111/cge.13036] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2017] [Revised: 03/27/2017] [Accepted: 04/09/2017] [Indexed: 12/19/2022]
Abstract
BACKGROUND Long QT syndrome (LQT) is a pro-arrhythmogenic condition with life-threatening complications. Fifteen genes have been associated with congenital LQT, however, the genetic causes remain unknown in more than 20% of cases. MATERIALS AND METHODS Eighteen patients with history of palpitations, pre-syncope, syncope and prolonged QT were referred to the Yale Cardiovascular Genetics Program. All subjects underwent whole-exome sequencing (WES) followed by confirmatory Sanger sequencing. Mutation burden analysis was carried out using WES data from 16 subjects with no identifiable cause of LQT. RESULTS Deleterious and novel SCN10A mutations were identified in 3 of the 16 patients (19%) with idiopathic LQT. These included 2 frameshifts and 1 missense variants (p.G810fs, p.R1259Q, and p.P1877fs). Further analysis identified 2 damaging SCN10A mutations with allele frequencies of approximately 0.2% (p.R14L and p.R1268Q) in 2 independent cases. None of the SCN10A mutation carriers had mutations in known arrhythmia genes. Damaging SCN10A mutations (p.R209H and p.R485C) were also identified in the 2 subjects on QT prolonging medications. CONCLUSION Our findings implicate SCN10A in LQT. The presence of frameshift mutations suggests loss-of-function as the underlying disease mechanism. The common association with atrial fibrillation suggests a unique mechanism of disease for this LQT gene.
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Affiliation(s)
- Maen D. Abou Ziki
- Section of Cardiovascular Medicine, Department of Internal Medicine, Yale University School of Medicine, New Haven, CT, 06510
| | - Sara B. Seidelmann
- Section of Cardiovascular Medicine, Department of Internal Medicine, Yale University School of Medicine, New Haven, CT, 06510
- Cardiovascular Division, Department of Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA, 02115
| | - Emily Smith
- Section of Cardiovascular Medicine, Department of Internal Medicine, Yale University School of Medicine, New Haven, CT, 06510
| | - Gourg Atteya
- Section of Cardiovascular Medicine, Department of Internal Medicine, Yale University School of Medicine, New Haven, CT, 06510
| | - Yuexin Jiang
- Section of Cardiovascular Medicine, Department of Internal Medicine, Yale University School of Medicine, New Haven, CT, 06510
| | - Rodolfo Gil Fernandes
- Section of Cardiovascular Medicine, Department of Internal Medicine, Yale University School of Medicine, New Haven, CT, 06510
| | - Mark A. Marieb
- Section of Cardiovascular Medicine, Department of Internal Medicine, Yale University School of Medicine, New Haven, CT, 06510
| | - Joseph G. Akar
- Section of Cardiovascular Medicine, Department of Internal Medicine, Yale University School of Medicine, New Haven, CT, 06510
| | - Arya Mani
- Section of Cardiovascular Medicine, Department of Internal Medicine, Yale University School of Medicine, New Haven, CT, 06510
- Deparetment of Genetics, Yale University School of Medicine, New Haven, CT, 06510
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10
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Dressler FF, Brado J, Odening KE. Electromechanical heterogeneity in the heart : A key to long QT syndrome? Herzschrittmacherther Elektrophysiol 2018; 29:43-47. [PMID: 29234865 DOI: 10.1007/s00399-017-0544-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2017] [Accepted: 11/24/2017] [Indexed: 06/07/2023]
Abstract
In the healthy heart, physiological heterogeneities in structure and in electrical and mechanical activity are crucial for normal, efficient excitation and pumping. Alterations of heterogeneity have been linked to arrhythmogenesis in various cardiac disorders such as long QT syndrome (LQTS). This inherited arrhythmia disorder is caused by mutations in different ion channel genes and is characterized by (heterogeneously) prolonged cardiac repolarization and increased risk for ventricular tachycardia, syncope and sudden cardiac death. Cardiac electrical and mechanical function are not independent of each other but interact in a bidirectional manner by electromechanical and mechano-electrical coupling. Therefore, changes in either process will affect the other. Recent experimental and clinical evidence suggests that LQTS, which is primarily considered an "electrical" disorder, also exhibits features of disturbed mechanical function and heterogeneity, which in turn appears to correlate with the risk of arrhythmia in the individual patient. In this review, we give a short overview of the current knowledge about physiological and pathological, long QT-related electrical and mechanical heterogeneity in the heart. Also, their respective roles for future risk prediction approaches in LQTS are discussed.
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Affiliation(s)
- F F Dressler
- Department of Cardiology and Angiology I, Heart Center, University of Freiburg, Hugstetter Str. 55, 79106, Freiburg, Germany
- Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - J Brado
- Department of Cardiology and Angiology I, Heart Center, University of Freiburg, Hugstetter Str. 55, 79106, Freiburg, Germany
- Faculty of Medicine, University of Freiburg, Freiburg, Germany
- Medizinische Klinik und Poliklinik I, Klinikum der Universität München, Munich, Germany
| | - K E Odening
- Department of Cardiology and Angiology I, Heart Center, University of Freiburg, Hugstetter Str. 55, 79106, Freiburg, Germany.
- Faculty of Medicine, University of Freiburg, Freiburg, Germany.
- Institute for Experimental Cardiovascular Medicine, Heart Center, University of Freiburg, Freiburg, Germany.
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11
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Wang J, Dai GY, Qin YM. [Identification of an SCN5A mutation in a Chinese pedigree with a history of syncope]. Zhonghua Er Ke Za Zhi 2017; 55:393-394. [PMID: 28482396 DOI: 10.3760/cma.j.issn.0578-1310.2017.05.019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
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12
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LI GUOLIANG, SHI RUI, WU JINE, HAN WENQI, ZHANG AIFENG, CHENG GONG, XUE XIAOLIN, SUN CHAOFENG. Association of the hERG mutation with long-QT syndrome type 2, syncope and epilepsy. Mol Med Rep 2016; 13:2467-75. [PMID: 26847485 PMCID: PMC4768985 DOI: 10.3892/mmr.2016.4859] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2014] [Accepted: 08/04/2015] [Indexed: 01/08/2023] Open
Abstract
Mutations in the human ether‑à‑go‑go‑related gene (hERG) are responsible for long‑QT syndrome (LQTS) type 2 (LQT2). In the present study, a heterozygous missense mutation (A561V) linked to LQT2, syncope and epilepsy was identified in the S5/pore region of the hERG protein. The mutation, A561V, was prepared and subcloned into hERG‑pcDNA3.0. Mutant plasmids were co‑transfected into HEK‑293 cells, which stably express wild‑type (WT) hERG, in order to mimic a heterozygous genotype, and the whole‑cell current was recorded using a patch‑clamp technique. Confocal microscopy was performed to evaluate the membrane distribution of the hERG channel protein using a green fluorescent protein tagged to the N‑terminus of hERG. A561V‑hERG decreased the amplitude of the WT‑hERG currents in a concentration‑dependent manner. In addition, A561V‑hERG resulted in alterations to activation, inactivation and recovery from inactivation in the hERG protein channels. Further evaluation of hERG membrane localization indicated that the A561V‑hERG mutant protein was unable to travel to the plasma membrane, which resulted in a trafficking‑deficient WT‑hERG protein. In conclusion, A561V‑hERG exerts a potent dominant‑negative effect on WT‑hERG channels, resulting in decreased hERG currents and impairment of hERG membrane localization. This may partially elucidate the clinical manifestations of LQTS patients who carry the A561V mutation.
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Affiliation(s)
- GUOLIANG LI
- Department of Cardiovascular Medicine, The First Affiliated Hospital of Xi'an Jiaotong University Health Science Center, Xi'an, Shaanxi 710061, P.R. China
| | - RUI SHI
- Department of Cardiovascular Medicine, The First Affiliated Hospital of Xi'an Jiaotong University Health Science Center, Xi'an, Shaanxi 710061, P.R. China
| | - JINE WU
- Department of Cardiovascular Medicine, The First Affiliated Hospital of Xi'an Jiaotong University Health Science Center, Xi'an, Shaanxi 710061, P.R. China
| | - WENQI HAN
- Department of Cardiovascular Medicine, The First Affiliated Hospital of Xi'an Jiaotong University Health Science Center, Xi'an, Shaanxi 710061, P.R. China
| | - AIFENG ZHANG
- Department of Cardiovascular Medicine, The Second Affiliated Hospital of Xi'an Jiaotong University Health Science Center, Xi'an, Shaanxi 710004, P.R. China
| | - GONG CHENG
- Department of Cardiovascular Medicine, Shaanxi Provincial People's Hospital, Xi'an, Shaanxi 710068, P.R. China
| | - XIAOLIN XUE
- Department of Cardiovascular Medicine, The First Affiliated Hospital of Xi'an Jiaotong University Health Science Center, Xi'an, Shaanxi 710061, P.R. China
| | - CHAOFENG SUN
- Department of Cardiovascular Medicine, The First Affiliated Hospital of Xi'an Jiaotong University Health Science Center, Xi'an, Shaanxi 710061, P.R. China
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Ichikawa M, Ohno S, Fujii Y, Ozawa J, Sonoda K, Fukuyama M, Kato K, Kimura H, Itoh H, Hayashi H, Horie M. Multigenerational Inheritance of Long QT Syndrome Type 2 in a Japanese Family. Intern Med 2016; 55:259-62. [PMID: 26831020 DOI: 10.2169/internalmedicine.55.6014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Congenital long QT syndrome (LQTS) is an important cause of sudden cardiac death in young people without any other structural disease. Mutations in the genes encoding the cardiac ion channels or associated proteins have been shown to result in ion channel dysfunction and thereby causing LQTS. We investigated a Japanese family with LQTS for four generations, with the female family members showing severe symptoms. We performed genetic tests for LQTS-related genes and identified a heterozygous KCNH2 mutation (p.K638del). In the family, the KCNH2 mutation had a very high multigenerational inheritance, and female genotype positives showed more severe phenotypes.
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Affiliation(s)
- Mari Ichikawa
- Department of Cardiovascular and Respiratory Medicine, Shiga University of Medical Science, Japan
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Ghouse J, Have CT, Weeke P, Bille Nielsen J, Ahlberg G, Balslev-Harder M, Appel EV, Skaaby T, Olesen SP, Grarup N, Linneberg A, Pedersen O, Haunsø S, Hastrup Svendsen J, Hansen T, Kanters JK, Salling Olesen M. Rare genetic variants previously associated with congenital forms of long QT syndrome have little or no effect on the QT interval. Eur Heart J 2015; 36:2523-9. [PMID: 26159999 DOI: 10.1093/eurheartj/ehv297] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/16/2015] [Accepted: 06/04/2015] [Indexed: 11/15/2022] Open
Abstract
AIMS We studied whether variants previously associated with congenital long QT syndrome (cLQTS) have an effect on the QTc interval in a Danish population sample. Furthermore, we assessed whether carriers of variants in cLQTS-associated genes are more prone to experience syncope compared with non-carriers and whether carriers have an increased mortality compared with non-carriers. METHODS AND RESULTS All genetic variants previously associated with cLQTS were surveyed using the Human Gene Mutation Database. We screened a Danish population-based sample with available whole-exome sequencing data (n = 870) and genotype array data (n = 6161) for putative cLQTS genetic variants. In total, 33 of 1358 variants previously reported to associate with cLQTS were identified. Of these, 10 variants were found in 8 or more individuals. Electrocardiogram results showed normal mean QTc intervals in carriers compared with non-carriers. Syncope data analysis between variant and non-variant carriers showed that 4 of 227 (1.8%) and 95 of 5861 (1.6%) individuals, respectively, had experienced syncope during follow-up (P = 0.80). There was no significant difference in overall mortality rates between carriers [7/217 (3.2%)] and non-carriers [301/6453 (4.7%)] (P = 0.24). CONCLUSION We present QTc data and register data, indicating that 26 cLQTS-associated variants neither had any effect on the QTc intervals nor on syncope propensity or overall mortality. Based on the frequency of individual gene variants, we suggest that the 10 variants frequently identified, assumed to relate to cLQTS, are less likely to associate with a dominant monogenic form of the disease.
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Affiliation(s)
- Jonas Ghouse
- The Danish National Research Foundation Centre for Cardiac Arrhythmia, Copenhagen, Denmark Laboratory of Molecular Cardiology, Department of Cardiology, The Heart Centre, University Hospital of Copenhagen, Rigshospitalet, 9312, Juliane Mariesvej 20, Copenhagen OE 2100, Denmark
| | - Christian Theil Have
- The Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Peter Weeke
- The Danish National Research Foundation Centre for Cardiac Arrhythmia, Copenhagen, Denmark Laboratory of Molecular Cardiology, Department of Cardiology, The Heart Centre, University Hospital of Copenhagen, Rigshospitalet, 9312, Juliane Mariesvej 20, Copenhagen OE 2100, Denmark
| | - Jonas Bille Nielsen
- The Danish National Research Foundation Centre for Cardiac Arrhythmia, Copenhagen, Denmark Laboratory of Molecular Cardiology, Department of Cardiology, The Heart Centre, University Hospital of Copenhagen, Rigshospitalet, 9312, Juliane Mariesvej 20, Copenhagen OE 2100, Denmark
| | - Gustav Ahlberg
- The Danish National Research Foundation Centre for Cardiac Arrhythmia, Copenhagen, Denmark Laboratory of Molecular Cardiology, Department of Cardiology, The Heart Centre, University Hospital of Copenhagen, Rigshospitalet, 9312, Juliane Mariesvej 20, Copenhagen OE 2100, Denmark
| | - Marie Balslev-Harder
- The Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Emil Vincent Appel
- The Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Tea Skaaby
- Research Centre for Prevention and Health, The Capital Region, Copenhagen, Denmark
| | - Søren-Peter Olesen
- The Danish National Research Foundation Centre for Cardiac Arrhythmia, Copenhagen, Denmark
| | - Niels Grarup
- The Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Allan Linneberg
- Research Centre for Prevention and Health, The Capital Region, Copenhagen, Denmark Department of Clinical Experimental Research, Glostrup University Hospital, Denmark Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark
| | - Oluf Pedersen
- The Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Stig Haunsø
- The Danish National Research Foundation Centre for Cardiac Arrhythmia, Copenhagen, Denmark Laboratory of Molecular Cardiology, Department of Cardiology, The Heart Centre, University Hospital of Copenhagen, Rigshospitalet, 9312, Juliane Mariesvej 20, Copenhagen OE 2100, Denmark Department of Medicine and Surgery, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Jesper Hastrup Svendsen
- The Danish National Research Foundation Centre for Cardiac Arrhythmia, Copenhagen, Denmark Laboratory of Molecular Cardiology, Department of Cardiology, The Heart Centre, University Hospital of Copenhagen, Rigshospitalet, 9312, Juliane Mariesvej 20, Copenhagen OE 2100, Denmark Department of Medicine and Surgery, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Torben Hansen
- The Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Jørgen Kim Kanters
- Laboratory of Experimental Cardiology, Department of Biomedicine, University of Copenhagen, Copenhagen, Denmark Department of Cardiology, Herlev and Gentofte University Hospitals, Copenhagen, Denmark
| | - Morten Salling Olesen
- The Danish National Research Foundation Centre for Cardiac Arrhythmia, Copenhagen, Denmark Laboratory of Molecular Cardiology, Department of Cardiology, The Heart Centre, University Hospital of Copenhagen, Rigshospitalet, 9312, Juliane Mariesvej 20, Copenhagen OE 2100, Denmark
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Nyegaard M, Overgaard MT, Søndergaard MT, Vranas M, Behr ER, Hildebrandt LL, Lund J, Hedley PL, Camm AJ, Wettrell G, Fosdal I, Christiansen M, Børglum AD. Mutations in calmodulin cause ventricular tachycardia and sudden cardiac death. Am J Hum Genet 2012; 91:703-12. [PMID: 23040497 DOI: 10.1016/j.ajhg.2012.08.015] [Citation(s) in RCA: 281] [Impact Index Per Article: 23.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2012] [Revised: 04/03/2012] [Accepted: 08/15/2012] [Indexed: 01/13/2023] Open
Abstract
Catecholaminergic polymorphic ventricular tachycardia (CPVT) is a devastating inherited disorder characterized by episodic syncope and/or sudden cardiac arrest during exercise or acute emotion in individuals without structural cardiac abnormalities. Although rare, CPVT is suspected to cause a substantial part of sudden cardiac deaths in young individuals. Mutations in RYR2, encoding the cardiac sarcoplasmic calcium channel, have been identified as causative in approximately half of all dominantly inherited CPVT cases. Applying a genome-wide linkage analysis in a large Swedish family with a severe dominantly inherited form of CPVT-like arrhythmias, we mapped the disease locus to chromosome 14q31-32. Sequencing CALM1 encoding calmodulin revealed a heterozygous missense mutation (c.161A>T [p.Asn53Ile]) segregating with the disease. A second, de novo, missense mutation (c.293A>G [p.Asn97Ser]) was subsequently identified in an individual of Iraqi origin; this individual was diagnosed with CPVT from a screening of 61 arrhythmia samples with no identified RYR2 mutations. Both CALM1 substitutions demonstrated compromised calcium binding, and p.Asn97Ser displayed an aberrant interaction with the RYR2 calmodulin-binding-domain peptide at low calcium concentrations. We conclude that calmodulin mutations can cause severe cardiac arrhythmia and that the calmodulin genes are candidates for genetic screening of individual cases and families with idiopathic ventricular tachycardia and unexplained sudden cardiac death.
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Affiliation(s)
- Mette Nyegaard
- Department of Biomedicine, Aarhus University, DK-8000 Aarhus, Denmark.
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16
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Sano Y, Shimizu F, Kawai M, Omoto M, Negoro K, Kurokawa T, Fujisawa H, Suzuki M, Okayama N, Suehiro Y, Hinoda Y, Kanda T. p.Arg332Cys mutation of NOTCH3 gene in two unrelated Japanese families with CADASIL. Intern Med 2011; 50:2833-8. [PMID: 22082899 DOI: 10.2169/internalmedicine.50.5418] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy is a cerebrovasuclar disease caused by NOTCH3 mutations, usually localized to exons 3 and 4. This report describes the clinical and neuroradiological findings of 2 subjects of two unrelated Japanese families who shared a common p.Arg332Cys mutation. The subject from family A presented syncope attacks as the sole clinical presentation at the beginning of his disease course. The subject from family B showed recurrent ischemic attacks, followed by a large intracranial hemorrhage. This is the first report to describe the detailed phenotypes of patients with a rare p.Arg332Cys mutation in Japan.
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Affiliation(s)
- Yasuteru Sano
- Department of Neurology and Clinical Neuroscience, Yamaguchi University Graduate School of Medicine, Japan
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17
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TAN ZN, DENG W, LUO YY, LI H, SUN SX, MENG SR, XU DL, PENG J. [Early repolarization syndrome and recurrent syncope in two Chinese pedigrees]. Zhonghua Xin Xue Guan Bing Za Zhi 2010; 38:801-804. [PMID: 21092648] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
OBJECTIVE to investigate the clinical characteristics in two families with early repolarization syndrome (ERS) and recurrent syncope. METHOD all family members including the probands were screened with routine clinical examination, electrocardiography, echocardiography, Holter recording, chest x-ray, head-up tilt test and blood biochemistry. RESULTS there was no clinical evidence of organic heart disease in all members from the two families. Proband 1 showed recurrent syncope, ERS and repeated torsade de pointes ventricular tachycardia and ventricular fibrillation were documented with resting ECG. ERS was detected in one brother, one nephew and one son from him and all were free of cardiac events including syncope, cardiac arrest and sudden cardiac death. Proband 2 showed recurrent syncope, ERS and ST segment arched upward elevation in V(1)-V(3) were documented by ECG. His father suffered sudden cardiac death at the age of 65 and asymptomatic ERS was detected in one of his nephew. CONCLUSIONS ERS is not always linked with benign clinical course and can sometimes lead to repeated syncope, torsade de pointes ventricular tachycardia and ventricular fibrillation. Pedigree research is of importance for ERS.
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Affiliation(s)
- Zhen-ni TAN
- Department of Cardiology, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China
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Medeiros-Domingo A, Bhuiyan ZA, Tester DJ, Hofman N, Bikker H, van Tintelen JP, Mannens MM, Wilde AA, Ackerman MJ. The RYR2-encoded ryanodine receptor/calcium release channel in patients diagnosed previously with either catecholaminergic polymorphic ventricular tachycardia or genotype negative, exercise-induced long QT syndrome: a comprehensive open reading frame mutational analysis. J Am Coll Cardiol 2009; 54:2065-74. [PMID: 19926015 PMCID: PMC2880864 DOI: 10.1016/j.jacc.2009.08.022] [Citation(s) in RCA: 203] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/05/2009] [Revised: 08/28/2009] [Accepted: 08/30/2009] [Indexed: 12/20/2022]
Abstract
OBJECTIVES This study was undertaken to determine the spectrum and prevalence of mutations in the RYR2-encoded cardiac ryanodine receptor in cases with exertional syncope and normal corrected QT interval (QTc). BACKGROUND Mutations in RYR2 cause type 1 catecholaminergic polymorphic ventricular tachycardia (CPVT1), a cardiac channelopathy with increased propensity for lethal ventricular dysrhythmias. Most RYR2 mutational analyses target 3 canonical domains encoded by <40% of the translated exons. The extent of CPVT1-associated mutations localizing outside of these domains remains unknown as RYR2 has not been examined comprehensively in most patient cohorts. METHODS Mutational analysis of all RYR2 exons was performed using polymerase chain reaction, high-performance liquid chromatography, and deoxyribonucleic acid sequencing on 155 unrelated patients (49% females, 96% Caucasian, age at diagnosis 20 +/- 15 years, mean QTc 428 +/- 29 ms), with either clinical diagnosis of CPVT (n = 110) or an initial diagnosis of exercise-induced long QT syndrome but with QTc <480 ms and a subsequent negative long QT syndrome genetic test (n = 45). RESULTS Sixty-three (34 novel) possible CPVT1-associated mutations, absent in 400 reference alleles, were detected in 73 unrelated patients (47%). Thirteen new mutation-containing exons were identified. Two-thirds of the CPVT1-positive patients had mutations that localized to 1 of 16 exons. CONCLUSIONS Possible CPVT1 mutations in RYR2 were identified in nearly one-half of this cohort; 45 of the 105 translated exons are now known to host possible mutations. Considering that approximately 65% of CPVT1-positive cases would be discovered by selective analysis of 16 exons, a tiered targeting strategy for CPVT genetic testing should be considered.
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Affiliation(s)
| | - Zahurul A. Bhuiyan
- Department of Clinical Genetics, Academic Medical Center, University of Amsterdam, Netherlands
| | - David J. Tester
- Department of Molecular Pharmacology & Experimental Therapeutics, Mayo Clinic, Rochester MN USA
| | - Nynke Hofman
- Department of Clinical Genetics, Academic Medical Center, University of Amsterdam, Netherlands
| | - Hennie Bikker
- Department of Clinical Genetics, Academic Medical Center, University of Amsterdam, Netherlands
| | - J Peter van Tintelen
- Department of Genetics, University Medical Center Groningen, University of Groningen, the Netherlands
| | - Marcel M.A.M Mannens
- Department of Clinical Genetics, Academic Medical Center, University of Amsterdam, Netherlands
| | - Arthur A.M. Wilde
- Department of Clinical Genetics, Academic Medical Center, University of Amsterdam, Netherlands
- Department of Cardiology and Heart Failure Research Centre, Academic Medical Center, University of Amsterdam, Netherlands
| | - Michael J. Ackerman
- Department of Molecular Pharmacology & Experimental Therapeutics, Mayo Clinic, Rochester MN USA
- Department of Medicine/Division of Cardiovascular Diseases, Mayo Clinic, Rochester MN USA
- Department of Pediatrics/Division of Pediatric Cardiology, Mayo Clinic, Rochester MN USA
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Abstract
OBJECTIVES To identify patients at risk of sudden cardiac death (SCD) by analysis of clinical history. DESIGN A retrospective study of the Swedish cohort of 15-35 year olds having suffered an SCD during 1992-1999 and having undergone a forensic autopsy (162 individuals). We sought information in forensic, police and medical records and from interviews with family members. RESULTS Syncope/presyncope, chest pain, palpitations or dyspnoea were present in 92/162, unspecific symptoms such as fatigue, influenza, headache or nightmares in 35/162. Syncope/presyncope was most common (42/162). In 74 seeking medical attention, 32 had an ECG recorded (24 pathological). In 26 subjects there was a family history of SCD. CONCLUSIONS The patient seeking medical advice before suffering an SCD is characterized by one to three of the following: 1) cardiac-related symptoms or non-specific symptoms often after an infectious disease, 2) a pathological ECG, 3) a family history of SCD. In 6 out of 10 a cardiac diagnosis was not considered. We conclude that symptoms preceding SCD were common but often misinterpreted.
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Affiliation(s)
- Aase Wisten
- Department of Internal Medicine, Sunderby Hospital, Luleå, Sweden.
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20
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Abstract
This paper describes a family of nine siblings of whom five suffer from the surdocardiac syndrome. All five are deaf-mute and have medical histories typical of the syndrome, with frequent syncopal attacks during the childhood, often caused by stress. Two of these five siblings have not suffered more than single attacks since puberty and are still alive. The other three had had continuous frequent attacks into adult years and died in connection with syncopes at 20, 27 and 37 years of age. The diagnosis, pathogenesis, treatment and genetics of the syndrome are discussed.
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Abstract
Paroxysmal losses of consciousness and other episodic neurological symptoms have many causes. Distinguishing epileptic from non-epileptic disorders is fundamental to diagnosis, but even this basic dichotomy is often challenging and is certainly not new. In 1907, the British neurologist William Richard Gowers published his book The Border-land of Epilepsy in which he discussed paroxysmal conditions "in the border-land of epilepsy-near it, but not of it" and their clinical differentiation from epilepsy itself. Now, a century later, we revisit the epilepsy borderland, focusing on syncope, migraine, vertigo, parasomnias, and some rarer paroxysmal disorders. For each condition, we review the clinical distinction from epileptic seizures. We then integrate current understanding of the molecular pathophysiology of these disorders into this clinical framework. This analysis shows that, although the clinical manifestations of paroxysmal disorders are highly heterogeneous, striking similarities in molecular pathophysiology are seen among many epileptic and non-epileptic paroxysmal phenomena.
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Affiliation(s)
- Douglas E Crompton
- Epilepsy Research Centre, Department of Medicine (Neurology), University of Melbourne, Austin Health, Heidelberg, Victoria, Australia
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22
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Akkerhuis JM, Baars HF, Marcelis CLM, Akkerhuis KM, Wilde AAM. [Congenital long QT-syndrome: the cause of recurrent syncope and sudden death at a young age]. Ned Tijdschr Geneeskd 2007; 151:2357-2364. [PMID: 18019210] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Congenital long QT-syndrome (LQTS) was diagnosed in three patients. The first patient, a 10-year-old girl, presented with recurrent episodes of syncope during swimming and was diagnosed with type 1 LQTS. The second patient, a 36-year-old asymptomatic man, was accidentally diagnosed with type 2 LQTS. His family history revealed syncope and sudden death at a young age after auditory stimuli. Type 3 LQTS was diagnosed post-mortem in a 16-year-old boy who died during his sleep. All clinical diagnoses were confirmed by genetic testing. Congenital LQTS is one of the leading causes of sudden cardiac death at a young age. Mutations in genes encoding for myocardial ion channel proteins lead to a prolonged QT-interval and abnormal ST-T segments in the 12-lead ECG. Patients may present with syncope or sudden cardiac death caused by ventricular tachyarrhythmias. Genotype-specific differences in ECG-abnormalities and triggers for cardiac events may help to distinguish the type of LQTS and make possible the initiation of genotype-specific treatment before the results of genetic testing are known. Identification of the genetic substrate by genetic testing, genotype-specific treatment, and the possibility of treatment with an implantable cardioverter-defibrillator have all led to dramatic improvement in the prognosis of patients with LQTS. Therefore, young patients with unexplained recurrent syncope after specific stimuli and those with atypical forms of epilepsy should be referred for cardiologic evaluation in a specialised centre.
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Zhang Y, Zhou N, Jiang W, Peng J, Wan H, Huang C, Xie Z, Huang CLH, Grace AA, Ma A. A missense mutation (G604S) in the S5/pore region of HERG causes long QT syndrome in a Chinese family with a high incidence of sudden unexpected death. Eur J Pediatr 2007; 166:927-33. [PMID: 17171344 DOI: 10.1007/s00431-006-0346-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/14/2006] [Accepted: 10/12/2006] [Indexed: 10/23/2022]
Abstract
Long QT syndrome (LQTS) is characterized by abnormalities in cardiac repolarization that lead to prolongation of the electrocardiographic (ECG) QT interval. Mutations in the human ether-a-go-go-related gene (HERG, KCNH2) cause the chromosome 7-linked LQT2 form of congenital LQTS, which is characterized by a prolonged QT interval and a bifid T-wave with an increased susceptibility to life-threatening cardiac arrhythmias, especially in children. We describe the genotypic and phenotypic pedigree of a large Chinese family (n = 36) in which 11 members were diagnosed with LQTS on the basis of typical ECG patterns for LQT2. Symptomatic syncopal episodes appeared in seven members of this family at a young age; an additional four members had died suddenly at ages of 18, 19, 24 and 70 years, respectively. Screening for SCN5A and HERG candidate genes identified a heterozygous missense mutation 1810G-->A in exon 7 of HERG that leads to the substitution of the amino acid glycine by serine (G604S); this mutation was located in the S5/pore region of the HERG protein and was associated with a malignant phenotype. Ten of the family members carrying the mutation showed a prolongation of the corrected QT interval (QTc), and seven of these had experienced multiple syncopal episodes. The retrospective examination of documented ECG records revealed that one family member who had died suddenly also had a prolonged QT interval. This study is the first to demonstrate a close correlation between clinical phenotype and genotype with a 100% penetrance based on the pedigree of a Chinese family with LQT2.
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Affiliation(s)
- Yanmin Zhang
- Department of Pediatrics, First Affiliated Hospital, Cardiovascular Ion Channel Disease Laboratory, Ministry of Education, Medical College of Xi'an Jiaotong University, Xi'an, Shaanxi, People's Republic of China.
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Abstract
Norepinephrine is frequently elevated in postural tachycardia syndrome (POTS), a syndrome of heterogeneous etiology characterized by a >30 beats/min increase in heart rate with standing. Norepinephrine is synthesized from dopamine by dopamine-β-hydroxylase (DBH). The results of a preliminary study suggested that the T allele frequency of the DBH −1021C→T polymorphism is elevated in POTS. This allele correlates with low DBH activity and might predict reduced serum DBH activity in patients with POTS. To test the hypothesis that low DBH activity and the underlying −1021C→T polymorphism are associated with increased susceptibility to POTS, we measured serum DBH activity in POTS and determined its relationship to the DBH genotype and plasma norepinephrine. Serum DBH was similar for 83 normal volunteers and 42 patients with POTS: median (range) = 22.5 (0.5–94.2) and 19.6 (0.1–68.8) nmol·min−1·ml−1, respectively ( P = 0.282). The genotype frequencies for 254 control and 157 POTS patients were not different between groups (∼63% CC genotype and ∼5% TT genotype, P = 0.319). The T allele associated with lower serum DBH in both groups [control serum DBH = 15.7 (SD 12.3) and 35.1 nmol·min−1·ml−1(SD 18.6) for T carriers and noncarriers, respectively; POTS serum DBH = 8.2 (SD 5.6) and 28.5 nmol·min−1·ml−1(SD 14.7) for T carriers and noncarriers, respectively]. High DBH in POTS was linked to elevated plasma levels of norepinephrine. Although DBH activity and genotype are unlikely to be primary determinants of susceptibility to POTS, differences in DBH activity in POTS may reflect differences in the level of sympathetic activation.
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Affiliation(s)
- Emily M Garland
- Autonomic Dysfunction Center, AA3228 Medical Center North, Vanderbilt University, Nashville, TN 37232-2195, USA.
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Márquez MF, Hernández-Pacheco G, Hermosillo AG, Gómez JR, Cárdenas M, Vargas-Alarcón G. The Arg389Gly beta1-adrenergic receptor gene polymorphism and susceptibility to faint during head-up tilt test. Europace 2007; 9:585-8. [PMID: 17463065 DOI: 10.1093/europace/eum059] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
AIMS To investigate the association of the Gly389 allele with positive head-up tilt test (HUT) in a Mexican Mestizo population. METHODS AND RESULTS HUT results were compared between carriers (one or two copies of the Gly389 allele) and non-carriers (Arg389Arg genotype) of the Gly389 allele of the beta(1)AR gene in 50 patients with unexplained syncope. Thirty-three patients (66%) had a positive HUT. Patients with a positive HUT had a higher Gly389 allele frequency compared with those with a negative test (30.3 vs. 3%; OR 13; pC = 0.012). Moreover, when comparing positive HUT in passive drug-free phase, positive HUT in pharmacological (nitrate) phase, and negative (both phases), a decreasing gradient in the frequencies of the Gly389 allele was found among the three groups: 45.4, 22.7, and 3%, respectively. CONCLUSION An association of positive tilt table testing to a single nucleotide polymorphism with a Gly to Arg switch at position 389 of the beta(1)AR was found. This polymorphism may contribute to susceptibility to faint during orthostatic challenge.
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Affiliation(s)
- M F Márquez
- Department of Electrocardiology, Instituto Nacional de Cardiología Ignacio Chávez, Mexico City, Mexico
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Betge S, Schulze-Bahr E, Fitzek C, Pfeifer R, Figulla HR, Witte OW, Isenmann S. Long-QT-Syndrom als Differenzialdiagnose einer Grand-Mal-Epilepsie. Nervenarzt 2006; 77:1210-7. [PMID: 16969682 DOI: 10.1007/s00115-006-2118-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
A 24-year-old female with a history of epileptic seizures was admitted after prolonged cardiac resuscitation. The clinical course together with additional examinations led to the diagnosis of severe hypoxic cerebral damage, with poor prognosis for neurological outcome. In her initial ECG, as in the ECGs of several family members, QT prolongation was diagnosed. Meticulous history taking and ensuing genetic analysis led to the diagnosis of familial long QT syndrome (LQTS) with a mutation in the LQT-2 gene (HERG). In retrospect, the previous seizure episodes have to be considered cardiac syncopes. Two family members had previously died suddenly, and ECG and genetic analysis revealed that a total of eight family members were affected. These relatives were prophylactically treated with beta blockers or supplied with automated implantable cardioverter defibrillating devices. The literature concerning LQTS, diagnosis and prognosis of cerebral hypoxic damage, and differentiation between seizures and cardiac syncopes is discussed.
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Affiliation(s)
- S Betge
- Klinik für Innere Medizin I, Universitätsklinikum der Friedrich-Schiller-Universität, Jena, Deutschland
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O'Leary DD, Hughson RL, Shoemaker JK, Greaves DK, Watenpaugh DE, Macias BR, Hargens AR. Heterogeneity of responses to orthostatic stress in homozygous twins. J Appl Physiol (1985) 2006; 102:249-54. [PMID: 17008441 DOI: 10.1152/japplphysiol.00240.2006] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Early analysis into the role of genetics on cardiovascular regulation has been accomplished by comparing blood pressure and heart rate in homozygous twins during unstressed, resting physiological conditions. However, many variables, including cognitive and environmental factors, contribute to the regulation of cardiovascular hemodynamics. Therefore, the purpose of this study was to determine the hemodynamic response of identical twins to an orthostatic stress, ranging from supine rest to presyncope. Heart rate, arterial blood pressure, middle cerebral artery blood velocity, an index of cerebrovascular resistance, cardiac output, total peripheral resistance, and end-tidal carbon dioxide were measured in 16 healthy monozygotic twin pairs. Five minutes of supine resting baseline data were collected, followed by 5 min of 60 degrees head-up tilt. After 5 min of head-up tilt, lower body negative pressure was applied in increments of 10 mmHg every 3 min until the onset of presyncope, at which time the subject was returned to the supine position for a 5-min recovery period. The data indicate that cardiovascular regulation under orthostatic stress demonstrates a significant degree of variance between identical twins, despite similar orthostatic tolerance. As the level of stress increases, so does the difference in the cardiovascular response within a twin pair. The elevated variance with increasing stress may be due to an increase in the role of environmental factors, as the influential role of genetics nears a functional limit. Therefore, although orthostatic tolerance times were very similar between identical twins, the mechanism involved in sustaining cardiovascular function during increasing stress was different.
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Affiliation(s)
- D D O'Leary
- Department of Community Health Sciences, Brock University, St. Catharines, Ontario, Canada.
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Lucas KE, Armenian HK, Petersen GM, Rowe PC. Familial aggregation of fainting in a case–control study of neurally mediated hypotension patients who present with unexplained chronic fatigue. ACTA ACUST UNITED AC 2006; 8:846-51. [PMID: 16920765 DOI: 10.1093/europace/eul092] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
AIMS We hypothesized that family history of fainting is a risk factor for adult-onset neurally mediated hypotension (NMH) in patients who present with chronic fatigue rather than fainting. METHODS AND RESULTS A nested case-control study of Gulf War veterans gathered fainting histories directly from 197 first-degree relatives of 16 fatigued NMH cases, 26 fatigued controls, and 17 healthy controls. NMH status was determined by tilt testing. Female relatives of fatigued controls reported more fainting than female relatives of cases (P<0.01); there were no significant differences in the frequency of fainting in male relatives by case or control status, or in either gender by age at first faint or by familial relationship to the proband. The odds of NMH patients giving any family history of fainting were 0.56 (95% CI 0.15, 2.07). Recurrence risks calculated using lifetime prevalences of fainting in male military personnel of similar age to our participants were low (1.5-1.7) and did not differ by case or control status. CONCLUSION Family history of fainting is not a risk factor for adult-onset NMH in fatigued veterans. Our findings may differ from other studies of familial aggregation in NMH because of study methods or because NMH-fatiguers may differ from NMH-fainters.
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Affiliation(s)
- Katherine E Lucas
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, 615 N. Wolfe Street, E6148, Baltimore, MD 21205, USA.
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di Barletta MR, Viatchenko-Karpinski S, Nori A, Memmi M, Terentyev D, Turcato F, Valle G, Rizzi N, Napolitano C, Gyorke S, Volpe P, Priori SG. Clinical phenotype and functional characterization of CASQ2 mutations associated with catecholaminergic polymorphic ventricular tachycardia. Circulation 2006; 114:1012-9. [PMID: 16908766 DOI: 10.1161/circulationaha.106.623793] [Citation(s) in RCA: 154] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Four distinct mutations in the human cardiac calsequestrin gene (CASQ2) have been linked to catecholaminergic polymorphic ventricular tachycardia (CPVT). The mechanisms leading to the clinical phenotype are still poorly understood because only 1 CASQ2 mutation has been characterized in vitro. METHODS AND RESULTS We identified a homozygous 16-bp deletion at position 339 to 354 leading to a frame shift and a stop codon after 5aa (CASQ2(G112+5X)) in a child with stress-induced ventricular tachycardia and cardiac arrest. The same deletion was also identified in association with a novel point mutation (CASQ2(L167H)) in a highly symptomatic CPVT child who is the first CPVT patient carrier of compound heterozygous CASQ2 mutations. We characterized in vitro the properties of CASQ2 mutants: CASQ2(G112+5X) did not bind Ca2+, whereas CASQ2(L167H) had normal calcium-binding properties. When expressed in rat myocytes, both mutants decreased the sarcoplasmic reticulum Ca2+-storing capacity and reduced the amplitude of I(Ca)-induced Ca2+ transients and of spontaneous Ca2+ sparks in permeabilized myocytes. Exposure of myocytes to isoproterenol caused the development of delayed afterdepolarizations in CASQ2(G112+5X). CONCLUSIONS CASQ2(L167H) and CASQ2(G112+5X) alter CASQ2 function in cardiac myocytes, which leads to reduction of active sarcoplasmic reticulum Ca2+ release and calcium content. In addition, CASQ2(G112+5X) displays altered calcium-binding properties and leads to delayed afterdepolarizations. We conclude that the 2 CASQ2 mutations identified in CPVT create distinct abnormalities that lead to abnormal intracellular calcium regulation, thus facilitating the development of tachyarrhythmias.
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Postma AV, Denjoy I, Kamblock J, Alders M, Lupoglazoff JM, Vaksmann G, Dubosq-Bidot L, Sebillon P, Mannens MMAM, Guicheney P, Wilde AAM. Catecholaminergic polymorphic ventricular tachycardia: RYR2 mutations, bradycardia, and follow up of the patients. J Med Genet 2006; 42:863-70. [PMID: 16272262 PMCID: PMC1735955 DOI: 10.1136/jmg.2004.028993] [Citation(s) in RCA: 203] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
BACKGROUND The aim of the study was to assess underlying genetic cause(s), clinical features, and response to therapy in catecholaminergic polymorphic ventricular tachycardia (CPVT) probands. METHODS AND RESULTS We identified 13 missense mutations in the cardiac ryanodine receptor (RYR2) in 12 probands with CPVT. Twelve were new, of which two are de novo mutations. A further 11 patients were silent gene carriers, suggesting that some mutations are associated with low penetrance. A marked resting sinus bradycardia off drugs was observed in all carriers. On beta blocker treatment, 98% of the RYR2 mutation carriers remained symptom free with a median follow up of 2 (range: 2-37) years. CONCLUSION CPVT patients with RYR2 mutation have bradycardia regardless of the site of the mutation, which could direct molecular diagnosis in (young) patients without structural heart disease presenting with syncopal events and a slow heart rate but with normal QTc at resting ECG. Treatment with beta blockers has been very effective in our CPVT patients during initial or short term follow up. Given the risk of sudden death and the efficacy of beta blocker therapy, the identification of large numbers of RYR2 mutations thus calls for genetic screening, early diagnosis, and subsequent preventive strategies.
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Haunsø S, Christiansen M, Kjeldsen KP. [Cardiac syncope--unexpected sudden cardiac death]. Ugeskr Laeger 2006; 168:2536. [PMID: 16824405] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
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Bundgaard H, Havndrup O, Christiansen M, Andersen PS, Jensen HK, Svendsen JH, Kjeldsen KP. [Long QT syndrome--genes, mechanisms and risks. Indication for genetic family screening?]. Ugeskr Laeger 2006; 168:2537-42. [PMID: 16824406] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Inherited long QT syndrome (LQTS) is a cardiac disease characterised by episodes of ventricular tachyarrhythmia, presenting as syncope or sudden death. Untreated, the annual mortality rate is 1-2%. Sudden death has been reported as the first manifestation of the disease in some cases. Therefore, early (pre-symptomatic) diagnosis and management may save lives. However, clinically false negative relatives are also at risk of sudden death. On this basis we conclude assessment of relatives should be extended with genetic testing.
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Affiliation(s)
- Henning Bundgaard
- H:S Rigshospitalet, Hjertecentret, Statens Serum Institut, Klinisk Biokemisk Afdeling, og Arhus Universitetshospital, Skejby Sygehus, Hjertemedicinsk Afdeling.
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Terentyev D, Nori A, Santoro M, Viatchenko-Karpinski S, Kubalova Z, Gyorke I, Terentyeva R, Vedamoorthyrao S, Blom NA, Valle G, Napolitano C, Williams SC, Volpe P, Priori SG, Gyorke S. Abnormal interactions of calsequestrin with the ryanodine receptor calcium release channel complex linked to exercise-induced sudden cardiac death. Circ Res 2006; 98:1151-8. [PMID: 16601229 DOI: 10.1161/01.res.0000220647.93982.08] [Citation(s) in RCA: 148] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Catecholaminergic polymorphic ventricular tachycardia (CPVT) is a familial arrhythmogenic disorder associated with mutations in the cardiac ryanodine receptor (RyR2) and cardiac calsequestrin (CASQ2) genes. Previous in vitro studies suggested that RyR2 and CASQ2 interact as parts of a multimolecular Ca(2+)-signaling complex; however, direct evidence for such interactions and their potential significance to myocardial function remain to be determined. We identified a novel CASQ2 mutation in a young female with a structurally normal heart and unexplained syncopal episodes. This mutation results in the nonconservative substitution of glutamine for arginine at amino acid 33 of CASQ2 (R33Q). Adenoviral-mediated expression of CASQ2(R33Q) in adult rat myocytes led to an increase in excitation-contraction coupling gain and to more frequent occurrences of spontaneous propagating (Ca2+ waves) and local Ca2+ signals (sparks) with respect to control cells expressing wild-type CASQ2 (CASQ2WT). As revealed by a Ca2+ indicator entrapped inside the sarcoplasmic reticulum (SR) of permeabilized myocytes, the increased occurrence of spontaneous Ca2+ sparks and waves was associated with a dramatic decrease in intra-SR [Ca2+]. Recombinant CASQ2WT and CASQ2R33Q exhibited similar Ca(2+)-binding capacities in vitro; however, the mutant protein lacked the ability of its WT counterpart to inhibit RyR2 activity at low luminal [Ca2+] in planar lipid bilayers. We conclude that the R33Q mutation disrupts interactions of CASQ2 with the RyR2 channel complex and impairs regulation of RyR2 by luminal Ca2+. These results show that intracellular Ca2+ cycling in normal heart relies on an intricate interplay of CASQ2 with the proteins of the RyR2 channel complex and that disruption of these interactions can lead to cardiac arrhythmia.
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Affiliation(s)
- Dmitry Terentyev
- Department of Physiology and Cell Biology, Heart and Lung Research Institute, Ohio State University, Columbus, OH 43210, USA
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Sánchez Navarro JJ, Monge Aramburu JM, Pérez-Macías Martín OM. Historia familiar con síndrome de Brugada: a propósito de un caso. Rev Clin Esp 2006; 206:112-4. [PMID: 16527176 DOI: 10.1157/13085368] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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35
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Spring PJ, Kok C, Nicholson GA, Ing AJ, Spies JM, Bassett ML, Cameron J, Kerlin P, Bowler S, Tuck R, Pollard JD. Autosomal dominant hereditary sensory neuropathy with chronic cough and gastro-oesophageal reflux: clinical features in two families linked to chromosome 3p22-p24. ACTA ACUST UNITED AC 2006; 128:2797-810. [PMID: 16311270 DOI: 10.1093/brain/awh653] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Autosomal dominant hereditary sensory neuropathy (HSN I) is a clinically and genetically heterogeneous group of disorders, and in some families it is due to mutations in the serine palmitoyltransferase (SPTLC1) gene. We have characterized two families with HSN I associated with cough and gastro-oesophageal reflux (GOR). From a large Australian family, 27 individuals and from a smaller family, 11 individuals provided clinical information and blood for genetic analysis. Affected individuals had an adult onset of paroxysmal cough, GOR and distal sensory loss. Cough could be triggered by noxious odours or by pressure in the external auditory canal (Arnold's ear-cough reflex). Other features included throat clearing, hoarse voice, cough syncope and sensorineural hearing loss. Neurophysiological and pathological studies demonstrated a sensory axonal neuropathy. Gastric emptying studies were normal, and autonomic function and sweat tests were either normal or showed distal hypohidrosis. Cough was likely to be due to a combination of denervation hypersensitivity of the upper airways and oesophagus, and prominent GOR. Most affected individuals were shown on 24 h ambulatory oesophageal pH monitoring to have multiple episodes of GOR, closely temporally associated with coughing. Hoarse voice was probably attributable to acid-induced laryngeal damage, and there was no evidence of vocal cord palsy. No other cause for cough was found on most respiratory or otorhinological studies. Linkage to chromosome 3p22-p24 has been found in both families, with no evidence of linkage to loci for known HSN I, autosomal dominant hereditary motor and sensory neuropathy, hereditary GOR or triple A syndrome. These families represent a genetically novel variant of HSN I, with a distinctive cough owing to involvement of the upper aerodigestive tract.
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Affiliation(s)
- Penelope J Spring
- Institute of Clinical Neurosciences, Royal Prince Alfred Hospital and University of Sydney, Australia.
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Meregalli PG, Wilde AAM, Tan HL. Pathophysiological mechanisms of Brugada syndrome: depolarization disorder, repolarization disorder, or more? Cardiovasc Res 2006; 67:367-78. [PMID: 15913579 DOI: 10.1016/j.cardiores.2005.03.005] [Citation(s) in RCA: 264] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/25/2005] [Revised: 03/08/2005] [Accepted: 03/10/2005] [Indexed: 10/25/2022] Open
Abstract
After its recognition as a distinct clinical entity, Brugada syndrome is increasingly recognized worldwide as an important cause of sudden cardiac death. Brugada syndrome exhibits autosomal dominant inheritance with SCN5A, which encodes the cardiac sodium channel, as the only gene with a proven involvement in 20-30% of patients. Its signature feature is ST segment elevation in right precordial ECG leads and predisposition to malignant ventricular tachyarrhythmias. The pathophysiological mechanism of ST elevation and ventricular tachyarrhythmia, two phenomena strongly related, is controversial. Here, we review clinical and experimental studies as they provide evidence to support or disprove the two hypotheses on the mechanism of Brugada syndrome that currently receive the widest support: (1) nonuniform abbreviation of right ventricular epicardial action potentials ("repolarization disorder"), (2) conduction delay in the right ventricular outflow tract ("depolarization disorder"). We also propose a schematic representation of the depolarization disorder hypothesis. Moreover, we review recent evidence to suggest that other derangements may also contribute to the pathophysiology of Brugada syndrome, in particular, right ventricular structural derangements. In reviewing these studies, we conclude that, similar to most diseases, it is likely that Brugada syndrome is not fully explained by one single mechanism. Rather than adhering to the notion that Brugada syndrome is a monofactorial disease, we should aim for clarification of the contribution of various pathophysiological mechanisms in individual Brugada syndrome patients and tailor therapy considering each of these mechanisms.
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Affiliation(s)
- Paola G Meregalli
- Department of Cardiology, Room M0-105, Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands
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Probst V, Evain S, Gournay V, Marie A, Schott JJ, Boisseau P, LE Marec H. Monomorphic Ventricular Tachycardia Due to Brugada Syndrome Successfully Treated by Hydroquinidine Therapy in a 3-Year-Old Child. J Cardiovasc Electrophysiol 2006; 17:97-100. [PMID: 16426410 DOI: 10.1111/j.1540-8167.2005.00329.x] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Mutations in the SCN5A gene can cause Brugada syndrome, a genetically inherited form of idiopathic ventricular fibrillation. We describe the case of a 3-year-old child with a structurally normal heart presenting with monomorphic ventricular tachycardia. Her electrocardiogram suggested a Brugada syndrome and the diagnosis was confirmed by the identification of a Brugada syndrome in her mother and in two other family members. Genetic study led to the identification of a c.2516T-->C SCN5A mutation. The child was treated with quinidine therapy without recurrence of arrhythmic events for a time period of 16 months.
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Affiliation(s)
- Vincent Probst
- Department of Cardiology and Unité INSERM U533, Institut du thorax, CHU de Nantes, Nantes, France.
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Bracha HS, Yoshioka DT, Masukawa NK, Stockman DJJ. Evolution of the human fear-circuitry and acute sociogenic pseudoneurological symptoms: the Neolithic balanced-polymorphism hypothesis. J Affect Disord 2005; 88:119-29. [PMID: 16111764 DOI: 10.1016/j.jad.2005.05.013] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/10/2004] [Accepted: 05/16/2005] [Indexed: 11/28/2022]
Abstract
In light of the increasing threat of large-scale massacres such as terrorism against non-combatants (civilians), more attention is warranted not only to posttraumatic stress disorder (PTSD) but also to acute sociogenic pseudoneurological ("conversion") symptoms, especially epidemic sociogenic symptoms. We posit that conversion disorders are etiologically related to specific evolutionary pressures (inescapable threats to life) in the late stage of the human environment of evolutionary adaptedness (EEA). Bracha et al. have recently argued that from the neuroevolutionary perspective, medically unexplained efferent vasovagal syncope and medically unexplained craniofacial musculoskeletal pain in young otherwise healthy individuals, may be taxonomized as stress and fear-circuitry disorders. In the present article, we extend neuroevolutionary perspectives to acute pseudoneurological sociogenic ("conversive") symptoms: psychogenic non-epileptic attacks ("pseudoseizures"), epidemic sociogenic disorders (DSM-IV-TR Epidemic "Hysteria"), conversive motor deficits (pseudo-paralysis and pseudo-cerebellar symptoms), and psychogenic blindness. We hypothesize that these perplexing pseudoneurological stress-triggered symptoms, which constitute psychopathology in extant humans, are traceable to allele-variant polymorphisms which spread during the Neolithic EEA. During Neolithic warfare, conversive symptoms may have increased the survival odds for some non-combatants by visually (i.e., "non-verbally") signaling to predatory conspecifics that one does not present a danger. This is consistent with the age and sex pattern of conversive disorders. Testable and falsifiable predictions are presented; e.g., at the genome-transcriptome interface, one of the major oligogenic loci involved in conversive spectrum disorders may carry a developmentally sensitive allele in a stable polymorphism (balanced polymorphism) in which the gene expression mechanism is gradually suppressed by pleiotropic androgens especially dehydroxyepiandrosterone sulfate (DHEA-S). Taxonomic implications for the much-needed rapprochement between the forthcoming Diagnostic and Statistical Manual for Mental Disorders, Fifth Edition (DSM-V) and the International Classification of Diseases (ICD) are discussed.
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Affiliation(s)
- H Stefan Bracha
- National Center for Posttraumatic Stress Disorder, Department of Veterans Affairs, Pacific Islands Health Care System, Spark M. Matsunaga Medical Center, 1132 Bishop St. #307, Honolulu, HI 96813, USA.
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Fazelifar AF, Arya A, Haghjoo M, Sadr-Ameli MA. Familial Atrial Standstill in Association with Dilated Cardiomyopathy. Pacing and Clinical Electrophysiology 2005; 28:1005-8. [PMID: 16176547 DOI: 10.1111/j.1540-8159.2005.00198.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
. Atrial standstill is an extremely uncommon arrhythmia that rarely appears to be familial and genetically determined. Atrial standstill has been associated with several conditions including, but not restricted to, congenital heart disease, valvular heart disease, conduction disturbances, Brugada syndrome, myocardial infarction, and amyloidosis. Only a few cases of familial clustering of atrial standstill have been reported so far. This report represents a family with atrial standstill associated with syncope, dilated cardiomyopathy, and sudden cardiac death.
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Affiliation(s)
- Amir Farjam Fazelifar
- Department of Pacemaker and Electrophysiology, Rajaie Cardiovascular Medical Center, Iran University of Medical Sciences, Mellat Park, Vali-Asr Avenue, Tehran 1996911151, Iran
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O'Riordan S, Patton M, Schon F. Treatment of drop episodes in Coffin–Lowry syndrome. J Neurol 2005; 253:109-10. [PMID: 16021355 DOI: 10.1007/s00415-005-0895-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2005] [Revised: 03/14/2005] [Accepted: 03/22/2005] [Indexed: 10/25/2022]
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Khositseth A, Tester DJ, Will ML, Bell CM, Ackerman MJ. Identification of a common genetic substrate underlying postpartum cardiac events in congenital long QT syndrome. Heart Rhythm 2005; 1:60-4. [PMID: 15851119 DOI: 10.1016/j.hrthm.2004.01.006] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/16/2003] [Accepted: 01/27/2004] [Indexed: 10/25/2022]
Abstract
OBJECTIVES The aim of this study was to elucidate the genetic basis for long QT syndrome (LQTS) in patients with a personal or family history of postpartum cardiac events. BACKGROUND The postpartum period is a time of increased arrhythmogenic susceptibility in women with LQTS. METHODS Between August 1997 and May 2003, 388 unrelated patients (260 females, average age at diagnosis, 23 years, and average QTc, 482 ms) were referred to Mayo Clinic's Sudden Death Genomics Laboratory for LQTS genetic testing. Comprehensive mutational analysis of the 5 LQTS-causing channel genes was performed. The postpartum period was defined as the 20 weeks after delivery. Cardiac events included sudden cardiac death, aborted cardiac arrest, and syncope. The presence of a personal and/or family history of cardiac events during postpartum period was determined by review of the medical records and/or phone interviews and was blinded to the status of genetic testing. RESULTS Fourteen patients (3.6% of cohort) had personal (n = 4) and/or family history (n = 11) of cardiac events during the defined postpartum period. Thirteen of 14 patients (93%) possessed an LQT2 mutation and 1 had an LQT1 mutation. Postpartum cardiac events were found more commonly in patients with LQT2 (13 of 80, 16%) than in patients with LQT1 (1 of 103, <1%, P = .0001). CONCLUSIONS There is a relatively gene-specific molecular basis underlying cardiac events during the postpartum period in LQTS. Along with previous gene-specific associations involving swimming and LQT1 as well as auditory triggers and LQT2, this association between postpartum cardiac events and LQT2 can facilitate strategic genotyping.
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Affiliation(s)
- Anant Khositseth
- Department of Pediatric and Adolescent Medicine/Division of Pediatric Cardiology, Mayo Clinic College of Medicine, Rochester, Minnesota 55905, USA
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Bracha HS, Bracha AS, Williams AE, Ralston TC, Matsukawa JM. The human fear-circuitry and fear-induced fainting in healthy individuals. Clin Auton Res 2005; 15:238-41. [PMID: 15944875 DOI: 10.1007/s10286-005-0245-z] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2004] [Accepted: 11/30/2004] [Indexed: 10/25/2022]
Abstract
The Paleolithic-Threat hypothesis reviewed here posits that habitual efferent fainting can be traced back to fear-induced allelic polymorphisms that were selected into some genomes of anatomically, mitochondrially, and neurally modern humans (Homo sapiens sapiens) in the Mid-Paleolithic because of the survival advantage they conferred during periods of inescapable threat. We posit that during Mid-Paleolithic warfare an encounter with "a stranger holding a sharp object" was consistently associated with threat to life. A heritable hardwired or firm-wired (prepotentiated) predisposition to abruptly increase vagal tone and collapse flaccidly rather than freeze or attempt to flee or fight in response to an approaching sharp object, a minor injury, or the sight of blood, may have evolved as an alternative stress-induced fear-circuitry response. Such a stable (balanced) polymorphism for the hemodynamically "paradoxical" flaccid-immobility in response to these stimuli may have increased some non-combatants' chances of survival. This is consistent with the unusual age and sex pattern of fear-induced fainting. The Paleolithic-Threat hypothesis also predicts a link to various hypo-androgenic states (e. g. low dehydroxy-epiandrosterone-sulfate. We offer five predictions testable via epidemiological, clinical, and ethological/ primatological methods. The Paleolithic-Threat hypothesis has implications for research in the aftermath of man-made disasters, such as terrorism against civilians, a traumatic event in which this hypothesis predicts epidemics of fear-induced fainting.
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Affiliation(s)
- H Stefan Bracha
- National Center for Posttraumatic Stress Disorder, Dept. of Veterans Affairs, Pacific Islands Health Care System, Spark M. Matsunaga Medical Center, Honolulu, HI 96813-2830, USA.
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Ackerman MJ. Cardiac causes of sudden unexpected death in children and their relationship to seizures and syncope: genetic testing for cardiac electropathies. Semin Pediatr Neurol 2005; 12:52-8. [PMID: 15929465 DOI: 10.1016/j.spen.2005.02.002] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
The sentinel descriptions of congenital long QT syndrome (LQTS) under the eponyms of Jervell and Lange-Nielsen syndrome and Romano-Ward syndrome were provided in 1957 and the early 1960s. In 1995, the discipline of cardiac channelopathies was birthed formally with the landmark discoveries of cardiac channel mutations as the pathogenic basis for LQTS. Over the past decade, the discipline has expanded considerably being comprised of at least a dozen distinct heritable arrhythmia syndromes, several disease-susceptibility genes, and hundreds of implicated mutations. Previously confined to the purview of research testing, diagnostic genetic testing for several channelopathies is now available for routine clinical use.
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Affiliation(s)
- Michael J Ackerman
- Long QT Syndrome Clinic and Sudden Death Genomics Laboratory, Mayo Clinic College of Medicine, Mayo Clinic, Rochester, MN, USA.
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Brugada P, Brugada R, Antzelevitch C, Brugada J. The Brugada Syndrome. Arch Mal Coeur Vaiss 2005; 98:115-22. [PMID: 15787302] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
In 1992 a syndrome was described consisting of syncopal episodes and/or (resuscitated) sudden death in patients with a structurally normal heart and a characte ristic electrocardiogram (ECG) displaying a pattern resembling a right bundle branch block with ST segment elevation in leads V1 to V3. The disease is genetically determined with an autosomal dominant pattern of transmission in 50% of the familial cases. Several different mutations have been identified affecting the structure, function and trafficking of the sodium channel. The syndrome is ubiquitous. Its incidence and prevalence are difficult to estimate, but this disease may cause 4 to 10 sudden deaths per 10,000 inhabitants per year representing the most frequent cause of natural death in males younger than 50 in South Asia. The disease has been linked to the sudden infant death syndrome (SIDS) and to the sudden unexpected death syndrome (SUDS) by showing that the electrocardiogram and mutations are the same as in Brugada syndrome. The diagnosis is easily made by means of the ECG when it is typical. There exist, however, patients with concealed and intermittent electrocardiographic forms that make the diagnosis difficult. The ECG can be modulated by changes in autonomic balance, body temperature, glucose level and the administration of antiarrhythmic, neuroleptic and antimalaria drugs. Beta adrenergic stimulation normalizes the ECG. Loss of the action potential dome in right ventricular epicardium but not in endocardium underlies the ST segment elevation. Electrical heterogeneity within right ventricular epicardium leads to the development of closely coupled extrasystoles via phase 2 reentry that precipitate ventricular ,fibrillation. Antiarrhythmic drugs do not prevent sudden death in symptomatic or asymptomatic individuals. Implantation of an automatic cardioverter-defibrillator is the only currently proven effective therapy. Patients with frequent electrical storms may even need cardiac transplantation as last resort.
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Affiliation(s)
- P Brugada
- Cardiovascular Research and Teaching Institute Aalst, Cardiovascular Centre, Belgium
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Abstract
The endothelins are peptides with vasoconstricting and growth-promoting properties. Endothelin-1 (ET-1) is known with its direct positive inotropic and chronotropic effects on isolated heart and with growth effects. The aim of this pilot study was to investigate the frequency distribution of the common polymorphism of the ET-1 gene and its possible relation with hemodynamic consequences of malignant ventricular arrhythmias in patients with structural heart disease. We studied 26 consecutive patients with malignant ventricular arrhythmias and implantable cardioverterdefibrillators with a mean age of 62.7 +/- 12.2 years and a mean left ventricular ejection fraction of 0.37 +/- 11.0. Taq polymorphism of ET-1 was detected using our original polymerase chain reaction method. The polymerase chain reaction product with a length of 358 basepairs (bp) (primers 5'-CAA ACC GAT GTC CTC TGT A-3' and 5'-ACC AAA CAC ATT TCC CTA TT-3') in its non-mutated form contains a target sequence for TaqI restrictive enzyme, while a mutated product loses this cleavage site. Of 26 patients, nine (34%) had recurrent palpitations and eight (30.8%) had syncopes during their malignant arrhythmias. Nineteen patients were given amiodarone after implantable cardioverter-defibrillator insertion and seven were not treated with amiodarone. Fifteen patients had (++), 11 (+-) and 0 (- -) ET-1 genotype. The risk for syncopes was associated with the (++) genotype of the ET-1 gene (P = 0.01). Patients receiving amiodarone had significantly higher frequency of the (++) genotype (P = 0.011). All our results indicate that the presence of the ET-1 genotype (++) in patients with structural heart disease, severe left ventricular dysfunction and malignant ventricular arrhythmias increases the risk for these patients of hemodynamic collapse during these arrhythmias.
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Affiliation(s)
- Milan Kozák
- Department of Cardiology and Medicine, Medical Faculty, Masaryk University, Brno, Czech Republic.
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Fox WC, Lockette W. Unexpected syncope and death during intense physical training: evolving role of molecular genetics. Aviat Space Environ Med 2003; 74:1223-30. [PMID: 14692463] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 04/27/2023]
Abstract
Special operations forces (SOF) undergo an unparalleled degree of physical training. The medical officer responsible for these personnel must often deal with episodes of syncope that cannot be readily explained. In the past, loss of consciousness during heavy physical exertion was attributed to inadequate fluid intake resulting in dehydration or abnormalities in temperature regulation. However, many of those diagnoses, in retrospect were probably incorrect. The occurrence of exercise-related syncope in multiple members of the same family suggested that there could be a genetic basis for the unexpected loss of consciousness during exercise. Intensive clinical examinations of these patients, coupled with current advances in molecular genetics, have shown this to be the case. We review some of the more common genetic abnormalities associated with exertion-related syncope. These syndromes should be considered by the medical officer presented with a patient having syncope of indeterminate cause.
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Affiliation(s)
- W Chris Fox
- Department of Physiology, University of Michigan, Ann Arbor, MI, USA
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Abstract
From a population-based epidemiologic cohort of children and adolescents who sought medical attention for syncope (n = 151), screening 12-lead electrocardiograms were obtained from 118 patients (79 female) to determine the frequency of significant QT prolongation. The distribution of heart rate corrected QT intervals (QTc) was compared with age- and sex-matched controls. Only one patient had QTc >470 ms.
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Affiliation(s)
- Anant Khositseth
- Department of Pediatric and Adolescent Medicine/Division of Pediatric Cardiology, Mayo Clinic and Foundation, Rochester, MN 55905, USA
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Mádle A. [Electrocardiography in the diagnosis of genetic heart diseases--the Brugada syndrome]. Vnitr Lek 2002; 48 Suppl 1:144-6. [PMID: 12744036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 03/02/2023]
Abstract
Electrocardiography celebrates its 100th anniversary but is still a useful and widely used examination method in cardiac diseases. Its importance can be demonstrated on its part in the diagnosis of a relatively newly described disease presented in this paper. It is a genetically conditioned anomaly of sodium channels of the cell membrane, called Brugada syndrome. The latter has a typical electrocardiographic tracing--elevations of the ST segment in leads V1-V3 along with a finding reminding of a right bundle branch block, absence of structural cardiac disease and an increased incidence of serious ventricular arrhythmias and sudden arrhythmic death.
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Affiliation(s)
- A Mádle
- II. interní klinika Fakultní nemocnice a LF UK, Plzen
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Bauce B, Rampazzo A, Basso C, Bagattin A, Daliento L, Tiso N, Turrini P, Thiene G, Danieli GA, Nava A. Screening for ryanodine receptor type 2 mutations in families with effort-induced polymorphic ventricular arrhythmias and sudden death: early diagnosis of asymptomatic carriers. J Am Coll Cardiol 2002; 40:341-9. [PMID: 12106942 DOI: 10.1016/s0735-1097(02)01946-0] [Citation(s) in RCA: 178] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
OBJECTIVES We sought to establish the role of genetic screening for ryanodine receptor type 2 (RyR2) gene mutations in families with effort-induced polymorphic ventricular arrhythmia (PVA), syncope and juvenile sudden death. BACKGROUND The RyR2 mutations have been associated with PVA, syncope and sudden death in response to physical or emotional stress. METHODS We studied 81 subjects (39 males and 42 females; mean age 31 +/- 20 years) belonging to eight families with pathogenic RyR2 mutations. All subjects underwent screening for RyR2 mutations, electrocardiography (ECG), 24-h Holter monitoring, signal-averaged electrocardiography (SAECG), two-dimensional echocardiography and exercise stress testing. Electrophysiologic (EP) study was performed in nine patients. RESULTS Six different RyR2 mutations were found in eight families. Forty-three family members carried the gene mutation. Of these, 28 (65%) showed effort-induced arrhythmic symptoms or signs and one died suddenly during follow-up. Family history revealed 19 juvenile cases of sudden death during effort or emotion. In two families sharing the same mutation, no subject presented with PVA during the stress test; thus, sudden death and syncope were the only clinical manifestations. The 12-lead ECG was normal in all but two subjects, whereas five patients showed positive late potentials on the SAECG. In 17 (39.5%) of 43 subjects, the two-dimensional echocardiogram revealed localized kinetic abnormalities and mild structural alterations of the right ventricle. The EP study was not able to induce PVA. CONCLUSIONS The absence of symptoms and PVA on the stress test in more than one-third of carriers of RyR2 mutations, as well as the lack of PVA inducibility by the EP study, underlies the importance of genetic screening for the early diagnosis of asymptomatic carriers and prevention of sudden death.
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Affiliation(s)
- Barbara Bauce
- Department of Cardiology, University of Padua Medical School, Via A. Gabelli, 86-35121 Padua, Italy
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