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Casimiro MC, Knollmann BC, Yamoah EN, Nie L, Vary JC, Sirenko SG, Greene AE, Grinberg A, Huang SP, Ebert SN, Pfeifer K. Targeted point mutagenesis of mouse Kcnq1: phenotypic analysis of mice with point mutations that cause Romano-Ward syndrome in humans. Genomics 2005; 84:555-64. [PMID: 15498462 DOI: 10.1016/j.ygeno.2004.06.007] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2004] [Revised: 06/08/2004] [Accepted: 06/09/2004] [Indexed: 01/23/2023]
Abstract
Inherited long QT syndrome is most frequently associated with mutations in KCNQ1, which encodes the primary subunit of a potassium channel. Patients with mutations in KCNQ1 may show only the cardiac defect (Romano-Ward syndrome or RWS) or may also have severe deafness (Jervell and Lange-Nielsen syndrome or JLNS). Targeted disruption of mouse Kcnq1 models JLNS in that mice are deaf and show abnormal ECGs. However, the phenotype is broader than that seen in patients. Most dramatically, the inner ear defects result in a severe hyperactivity/circling behavior, which may influence cardiac function. To understand the etiology of the cardiac phenotype in these mice and to generate a potentially more useful model system, we generated new mouse lines by introducing point mutations associated with RWS. The A340E line phenocopies RWS: the repolarization phenotype is inherited in a dominant manner and is observed independent of any inner ear defect. The T311I line phenocopies JLNS, with deafness associated with inner hair cell malfunction.
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Affiliation(s)
- Mathew C Casimiro
- Laboratory of Mammalian Genes and Development, NICHD/National Institutes of Health, Building 6B Room 2B-206, Bethesda, MD 20892, USA
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Oberti C, Wang L, Li L, Dong J, Rao S, Du W, Wang Q. Genome-wide linkage scan identifies a novel genetic locus on chromosome 5p13 for neonatal atrial fibrillation associated with sudden death and variable cardiomyopathy. Circulation 2004; 110:3753-9. [PMID: 15596564 PMCID: PMC1618875 DOI: 10.1161/01.cir.0000150333.87176.c7] [Citation(s) in RCA: 94] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
BACKGROUND Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia, and patients with AF have a significantly increased risk for ischemic stroke. Approximately 15% of all strokes are caused by AF. The molecular basis and underlying mechanisms and pathophysiology of AF remain largely unknown. METHODS AND RESULTS We have identified a large AF family with an autosomal recessive inheritance pattern. The AF in the family manifests with early onset at the fetal stage and is associated with neonatal sudden death and, in some cases, ventricular tachyarrhythmias and waxing and waning cardiomyopathy. Genome-wide linkage analysis was performed for 36 family members and generated a 2-point logarithm of the odds (LOD) score of 3.05 for marker D5S455. The maximum multipoint LOD score of 4.10 was obtained for 4 markers: D5S426, D5S493, D5S455, and D5S1998. Heterozygous carriers have significant prolongation of P-wave duration on ECGs compared with noncarriers (107 versus 85 ms on average; P=0.000012), but no differences between these 2 groups were detected for the PR interval, QRS complex, ST-segment duration, T-wave duration, QTc, and R-R interval (P>0.05). CONCLUSIONS Our findings demonstrate that AF can be inherited as an autosomal recessive trait and define a novel genetic locus for AF on chromosome 5p13 (arAF1). A genetic link between AF and prolonged P-wave duration was identified. This study provides a framework for the ultimate cloning of the arAF1 gene, which will increase the understanding of the fundamental molecular mechanisms of atrial fibrillation.
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MESH Headings
- Adolescent
- Adult
- Age of Onset
- Aged
- Aged, 80 and over
- Atrial Fibrillation/congenital
- Atrial Fibrillation/epidemiology
- Atrial Fibrillation/genetics
- Cardiomyopathies/genetics
- Cardiomyopathies/pathology
- Child
- Child, Preschool
- Chromosomes, Human, Pair 5/genetics
- Consanguinity
- DNA/genetics
- Death, Sudden, Cardiac/epidemiology
- Female
- Fetal Diseases/genetics
- Fetal Heart/physiopathology
- Genes, Recessive
- Genome, Human
- Genotype
- Heart Conduction System/physiopathology
- Humans
- Infant
- Infant, Newborn
- Lod Score
- Male
- Middle Aged
- Pedigree
- Tachycardia, Ventricular/genetics
- Uruguay/epidemiology
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Affiliation(s)
| | | | - Lin Li
- From the Center for Molecular Genetics, Department of Molecular Cardiology, Lerner Research Institute (C.O., L.W., L.L., J.D., S.R., W.D., Q.W.) and the Center for Cardiovascular Genetics, Department of Cardiovascular Medicine (C.O., L.W., L.L., J.D., S.R., W.D., Q.W.), The Cleveland Clinic Foundation; the Department of Molecular Medicine, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University (L.W., L.L., J.D., S.R., Q.W.), and the Department of Biological, Geological, and Environmental Sciences, Cleveland State University (W.D., Q.W.), Cleveland, Ohio; the Department of Cardiology, Ospedale Italiano Umberto I, Montevideo, Uruguay (C.O.); and Huazhong University of Science and Technology Human Genome Research Center, Wuhan, Hubei, P.R. China (Q.W.)
| | - Jiamei Dong
- From the Center for Molecular Genetics, Department of Molecular Cardiology, Lerner Research Institute (C.O., L.W., L.L., J.D., S.R., W.D., Q.W.) and the Center for Cardiovascular Genetics, Department of Cardiovascular Medicine (C.O., L.W., L.L., J.D., S.R., W.D., Q.W.), The Cleveland Clinic Foundation; the Department of Molecular Medicine, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University (L.W., L.L., J.D., S.R., Q.W.), and the Department of Biological, Geological, and Environmental Sciences, Cleveland State University (W.D., Q.W.), Cleveland, Ohio; the Department of Cardiology, Ospedale Italiano Umberto I, Montevideo, Uruguay (C.O.); and Huazhong University of Science and Technology Human Genome Research Center, Wuhan, Hubei, P.R. China (Q.W.)
| | - Shaoqi Rao
- From the Center for Molecular Genetics, Department of Molecular Cardiology, Lerner Research Institute (C.O., L.W., L.L., J.D., S.R., W.D., Q.W.) and the Center for Cardiovascular Genetics, Department of Cardiovascular Medicine (C.O., L.W., L.L., J.D., S.R., W.D., Q.W.), The Cleveland Clinic Foundation; the Department of Molecular Medicine, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University (L.W., L.L., J.D., S.R., Q.W.), and the Department of Biological, Geological, and Environmental Sciences, Cleveland State University (W.D., Q.W.), Cleveland, Ohio; the Department of Cardiology, Ospedale Italiano Umberto I, Montevideo, Uruguay (C.O.); and Huazhong University of Science and Technology Human Genome Research Center, Wuhan, Hubei, P.R. China (Q.W.)
| | - Wei Du
- From the Center for Molecular Genetics, Department of Molecular Cardiology, Lerner Research Institute (C.O., L.W., L.L., J.D., S.R., W.D., Q.W.) and the Center for Cardiovascular Genetics, Department of Cardiovascular Medicine (C.O., L.W., L.L., J.D., S.R., W.D., Q.W.), The Cleveland Clinic Foundation; the Department of Molecular Medicine, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University (L.W., L.L., J.D., S.R., Q.W.), and the Department of Biological, Geological, and Environmental Sciences, Cleveland State University (W.D., Q.W.), Cleveland, Ohio; the Department of Cardiology, Ospedale Italiano Umberto I, Montevideo, Uruguay (C.O.); and Huazhong University of Science and Technology Human Genome Research Center, Wuhan, Hubei, P.R. China (Q.W.)
| | - Qing Wang
- From the Center for Molecular Genetics, Department of Molecular Cardiology, Lerner Research Institute (C.O., L.W., L.L., J.D., S.R., W.D., Q.W.) and the Center for Cardiovascular Genetics, Department of Cardiovascular Medicine (C.O., L.W., L.L., J.D., S.R., W.D., Q.W.), The Cleveland Clinic Foundation; the Department of Molecular Medicine, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University (L.W., L.L., J.D., S.R., Q.W.), and the Department of Biological, Geological, and Environmental Sciences, Cleveland State University (W.D., Q.W.), Cleveland, Ohio; the Department of Cardiology, Ospedale Italiano Umberto I, Montevideo, Uruguay (C.O.); and Huazhong University of Science and Technology Human Genome Research Center, Wuhan, Hubei, P.R. China (Q.W.)
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Wedekind H, Schwarz M, Hauenschild S, Djonlagic H, Haverkamp W, Breithardt G, Wülfing T, Pongs O, Isbrandt D, Schulze-Bahr E. Effective long-term control of cardiac events with beta-blockers in a family with a common LQT1 mutation. Clin Genet 2004; 65:233-41. [PMID: 14756674 DOI: 10.1111/j.0009-9163.2004.00221.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The congenital long QT syndrome (LQTS) is characterized by a prolonged QT interval on the surface electrocardiogram and an increased risk of recurrent syncope and sudden cardiac death. Mutations in seven genes have been identified as the molecular basis of LQTS. beta-blockers are the treatment of choice to reduce cardiac symptoms. However, long-term follow-up of genotyped families with LQTS has been rarely reported. We have clinically followed a four-generation family with LQTS being treated with beta-blocker therapy over a period of 23 years. Seven family members were carriers of two amino acid alterations in cis (V254M-V417M) in the cardiac potassium channel gene KCNQ1. Voltage-clamp recordings of mutant KCNQ1 protein in Xenopus oocytes showed that only the V254M mutation reduced the IKs current and that the effect of the V417M variant was negligible. The family exhibited the complete clinical spectrum of the disease, from asymptomatic patients to victims of sudden death before beta-blocker therapy. There was no significant reduction in QTc (556 +/- 40 ms(1/2) before therapy, 494 +/- 20 ms(1/2) during 17 years of treatment; n = 5 individuals). Of nine family members, one female died suddenly before treatment, three females of the second generation were asymptomatic, and four individuals of the third and fourth generation were symptomatic. All mutation carriers were treated with beta-blockers and remained asymptomatic for a follow-up up to 23 years. Long-term follow-up of a LQT1 family with a common mutation (V254M) being on beta-blocker therapy was effective and safe. This study underscores the importance of long-term follow-up in families with specific LQT mutations to provide valuable information for clinicians for an appropriate antiarrhythmic treatment.
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Affiliation(s)
- H Wedekind
- Departments of Cardiology and Angiology,University of Münster, Albert-Schweitzer-Strasse 33, D-48149 Münster, Germany.
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Bhagavatula MK, Fan C, Shen GQ, Cassano J, Plow EF, Topol EJ, Wang Q. Transcription factor MEF2A mutations in patients with coronary artery disease. Hum Mol Genet 2004; 13:3181-8. [PMID: 15496429 PMCID: PMC1579761 DOI: 10.1093/hmg/ddh329] [Citation(s) in RCA: 81] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Coronary artery disease (CAD), including its most serious complication myocardial infraction (MI), is the leading cause of death in the US and developed countries. We recently discovered that a seven-amino acid deletion in MEF2A, a transcription factor with a high level of expression in the endothelium of coronary arteries, co-segregates with CAD/MI in one family, and it suppresses transcription activation activity of MEF2A by a dominant-negative mechanism. In this study, we used single-strand conformation polymorphism and DNA sequence analyses to identify mutations in MEF2A in 207 independent CAD/MI patients and 191 controls with normal angiograms. We identified three novel mutations in exon 7 of MEF2A in four of 207 CAD/MI patients (1.93%). No mutations were detected in the 191 controls. The mutations identified here include N263S identified in two independent CAD patients, P279L in one patient and his father with the diagnosis of CAD and G283D in one patient. These mutations are clustered within or close to the major transcriptional activation domain of MEF2A. They significantly reduce the transcriptional activation activity of MEF2A and act by a loss-of-function mechanism. The gene carriers with loss-of-function mutations appear to be associated with less severe CAD. These results suggest that CAD/MI can result from a spectrum of MEF2A transcription dysfunctions ranging from loss-of-function to dominant-negative suppression and that a significant percent of the CAD/MI population (1.93%) may carry mutations in MEF2A, although further definition of the prevalence of MEF2A mutations is warranted.
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Affiliation(s)
- M.R. Krishna Bhagavatula
- Department of Molecular Cardiology, Lerner Research Institute
- Center for Cardiovascular Genetics, Department of Cardiovascular Medicine, The Cleveland Clinic Foundation, Cleveland, OH 44195, USA and
- Department of Biological, Geological and Environmental Sciences, Cleveland State University, Cleveland, OH 44115, USA
| | - Chun Fan
- Department of Molecular Cardiology, Lerner Research Institute
- Center for Cardiovascular Genetics, Department of Cardiovascular Medicine, The Cleveland Clinic Foundation, Cleveland, OH 44195, USA and
| | - Gong-Qing Shen
- Department of Molecular Cardiology, Lerner Research Institute
- Center for Cardiovascular Genetics, Department of Cardiovascular Medicine, The Cleveland Clinic Foundation, Cleveland, OH 44195, USA and
| | - June Cassano
- Center for Cardiovascular Genetics, Department of Cardiovascular Medicine, The Cleveland Clinic Foundation, Cleveland, OH 44195, USA and
| | - Edward F. Plow
- Department of Molecular Cardiology, Lerner Research Institute
- Center for Cardiovascular Genetics, Department of Cardiovascular Medicine, The Cleveland Clinic Foundation, Cleveland, OH 44195, USA and
| | - Eric J. Topol
- Department of Molecular Cardiology, Lerner Research Institute
- Center for Cardiovascular Genetics, Department of Cardiovascular Medicine, The Cleveland Clinic Foundation, Cleveland, OH 44195, USA and
| | - Qing Wang
- Department of Molecular Cardiology, Lerner Research Institute
- Center for Cardiovascular Genetics, Department of Cardiovascular Medicine, The Cleveland Clinic Foundation, Cleveland, OH 44195, USA and
- Department of Biological, Geological and Environmental Sciences, Cleveland State University, Cleveland, OH 44115, USA
- *To whom correspondence should be addressed at: Center for Molecular Genetics/ND4-38, The Cleveland Clinic Foundation, 9500 Euclid Avenue, Cleveland, OH 44195, USA. Tel: +1 2164450570; Fax: +1 2164442682;
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