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Risi CM, Belknap B, White HD, Dryden K, Pinto JR, Chase PB, Galkin VE. High-resolution cryo-EM structure of the junction region of the native cardiac thin filament in relaxed state. PNAS NEXUS 2023; 2:pgac298. [PMID: 36712934 PMCID: PMC9832952 DOI: 10.1093/pnasnexus/pgac298] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Accepted: 12/15/2022] [Indexed: 12/23/2022]
Abstract
Cardiac contraction depends on molecular interactions among sarcomeric proteins coordinated by the rising and falling intracellular Ca2+ levels. Cardiac thin filament (cTF) consists of two strands composed of actin, tropomyosin (Tm), and equally spaced troponin (Tn) complexes forming regulatory units. Tn binds Ca2+ to move Tm strand away from myosin-binding sites on actin to enable actomyosin cross-bridges required for force generation. The Tn complex has three subunits-Ca2+-binding TnC, inhibitory TnI, and Tm-binding TnT. Tm strand is comprised of adjacent Tm molecules that overlap "head-to-tail" along the actin filament. The N-terminus of TnT (e.g., TnT1) binds to the Tm overlap region to form the cTF junction region-the region that connects adjacent regulatory units and confers to cTF internal cooperativity. Numerous studies have predicted interactions among actin, Tm, and TnT1 within the junction region, although a direct structural description of the cTF junction region awaited completion. Here, we report a 3.8 Å resolution cryo-EM structure of the native cTF junction region at relaxing (pCa 8) Ca2+ conditions. We provide novel insights into the "head-to-tail" interactions between adjacent Tm molecules and interactions between the Tm junction with F-actin. We demonstrate how TnT1 stabilizes the Tm overlap region via its interactions with the Tm C- and N-termini and actin. Our data show that TnT1 works as a joint that anchors the Tm overlap region to actin, which stabilizes the relaxed state of the cTF. Our structure provides insight into the molecular basis of cardiac diseases caused by missense mutations in TnT1.
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Affiliation(s)
- Cristina M Risi
- Department of Physiological Sciences, Eastern Virginia Medical School, Norfolk, VA 23507, USA
| | - Betty Belknap
- Department of Physiological Sciences, Eastern Virginia Medical School, Norfolk, VA 23507, USA
| | - Howard D White
- Department of Physiological Sciences, Eastern Virginia Medical School, Norfolk, VA 23507, USA
| | - Kelly Dryden
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, VA 22904, USA
| | - Jose R Pinto
- Department of Biomedical Sciences, Florida State University College of Medicine, Tallahassee, FL 32304, USA
| | - P Bryant Chase
- Department of Biological Science, Florida State University, Tallahassee, FL 32306, USA
| | - Vitold E Galkin
- Department of Physiological Sciences, Eastern Virginia Medical School, Norfolk, VA 23507, USA
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Taylor MRG, Robinson ML, Mestroni L. Analysis of Genetic Variations of Lamin A/C Gene (LMNA) by Denaturing High-Performance Liquid Chromatography. ACTA ACUST UNITED AC 2016; 9:625-8. [PMID: 15475483 DOI: 10.1177/1087057104266393] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The human LMNA gene, when mutated, has been shown to cause at least 7 human diseases: dilated cardiomyopathy, Emery Dreifuss muscular dystrophy, limb girdle muscular dystrophy, familial partial lipodystrophy, Charcot Marie tooth disease type II, mandibuloacral dysplasia, and Hutchinson-Gilford Progeria (OMIM #176670). This article describes a high-throughput method for screening the human lamin A/C ( LMNA) gene for genetic mutations and sequence variation using denaturing high-performance liquid chromatography (DHPLC). In the present study, 76 patients with dilated cardiomyopathy were screened for mutations using DHPLC and sequence analysis. Abnormal elution profiles were identified and sequenced on an ABI 377 automatic sequencer. Heterozygous LMNA mutations were detected in 8% of the affected patients. In addition, a number of intronic and exonic single nucleotide polymorphisms were identified. LMNA mutations are clinically relevant in at least 6 human diseases. This study provides a protocol for high-throughput LMNA analysis applicable both in the research and in the clinical diagnostic setting.
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Perfil clínico y pronóstico de las miocardiopatías causadas por mutaciones en el gen de la troponina T. Rev Esp Cardiol 2016. [DOI: 10.1016/j.recesp.2015.06.028] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Clinical and Prognostic Profiles of Cardiomyopathies Caused by Mutations in the Troponin T Gene. ACTA ACUST UNITED AC 2015; 69:149-58. [PMID: 26507537 DOI: 10.1016/j.rec.2015.06.025] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2015] [Accepted: 06/29/2015] [Indexed: 11/20/2022]
Abstract
INTRODUCTION AND AIMS Mutations in the troponin T gene (TTNT2) have been associated in small studies with the development of hypertrophic cardiomyopathy characterized by a high risk of sudden death and mild hypertrophy. We describe the clinical course of patients carrying mutations in this gene. METHODS We analyzed the clinical characteristics and prognosis of patients with mutations in the TNNT2 gene who were seen in an inherited cardiac disease unit. RESULTS Of 180 families with genetically studied cardiomyopathies, 21 families (11.7%) were identified as having mutations in TNNT2: 10 families had Arg92Gln, 5 had Arg286His, 3 had Arg278Cys, 1 had Arg92Trp, 1 had Arg94His, and 1 had Ile221Thr. Thirty-three additional genetic carriers were identified through family assessment. The study included 54 genetic carriers: 56% were male, and the mean average age was 41 ± 17 years. There were 33 cases of hypertrophic cardiomyopathy, 9 of dilated cardiomyopathy, and 1 of noncompaction cardiomyopathy, and maximal myocardial thickness was 18.5 ± 6mm. Ventricular dysfunction was present in 30% of individuals and a history of sudden death in 62%. During follow-up, 4 patients died and 14 (33%) received a defibrillator (8 probands, 6 relatives). Mean survival was 54 years. Carriers of Arg92Gln had early disease development, high penetrance, a high risk of sudden death, a high rate of defibrillator implantation, and a high frequency of mixed phenotype. CONCLUSIONS Mutations in the TNNT2 gene were more common in this series than in previous studies. The clinical and prognostic profiles depended on the mutation present. Carriers of the Arg92Gln mutation developed hypertrophic or dilated cardiomyopathy and had a significantly worse prognosis than those with other mutations in TNNT2 or other sarcomeric genes.
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Genotyping of Macrophage Migration Inhibitory Factor (MIF) CATT5–8 Repeat Polymorphism by Denaturing High-Performance Liquid Chromatography (DHPLC). Mol Biotechnol 2012; 54:874-9. [DOI: 10.1007/s12033-012-9636-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Page SP, Kounas S, Syrris P, Christiansen M, Frank-Hansen R, Andersen PS, Elliott PM, McKenna WJ. Cardiac Myosin Binding Protein-C Mutations in Families With Hypertrophic Cardiomyopathy. ACTA ACUST UNITED AC 2012; 5:156-66. [DOI: 10.1161/circgenetics.111.960831] [Citation(s) in RCA: 104] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Background—
Small selected cohort studies suggest that mutations in the cardiac myosin binding protein-C (MYBPC3) gene cause late-onset, clinically benign hypertrophic cardiomyopathy (HCM). The aim of this study was to test this hypothesis in a large series of families with HCM associated with MYBPC3 mutations.
Methods and Results—
The initial study population comprised 57 probands with 42 mutations (26 [61.9%] novel) in MYBPC3. Missense mutations (15, 45.6%) were the most frequent, and multiple mutations occurred in 4 (7.0%) probands. Another 110 mutation carriers were identified during familial evaluation; 38 were clinically affected with left ventricular hypertrophy ≥13 mm. Disease penetrance was, therefore, incomplete (56.9% in all mutation carriers, 34.5% in relatives), related to age (38.4% <40 versus 68.6% ≥40 years,
P
<0.001), and was greater in males than females (65.1% versus 48.1%,
P
=0.03). In 9 families (25 individuals) with the R502W mutation, there was marked heterogeneity in age at diagnosis (5 to 80 years), pattern of hypertrophy (11 none, 9 asymmetrical, 3 concentric, 1 apical, 1 eccentric), and prognosis (premature sudden death in 2 individuals compared with survival to advanced age in 6 individuals). During follow up of 7.9+/−4.5 years, in 82 clinically affected individuals the annual risk of sudden death and all cause mortality was 0.46% and 0.93% per year, respectively.
Conclusions—
Disease expression in families with HCM related to MYBPC3 mutations shows marked heterogeneity with incomplete, age-related, and gender specific penetrance. Importantly, complex genetic status is observed and should be considered when mutation analysis and cascade screening is used in the evaluation of at risk family members.
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Affiliation(s)
- Stephen P. Page
- From the Inherited Cardiovascular Disease Unit, The Heart Hospital, London, United Kingdom (S.P.P., S.K., P.S., P.M.E., W.J.M.); and Department of Clinical Biochemistry, Statens Serum Institut, Copenhagen, Denmark (M.C., R.F.-H., P.S.A.)
| | - Stavros Kounas
- From the Inherited Cardiovascular Disease Unit, The Heart Hospital, London, United Kingdom (S.P.P., S.K., P.S., P.M.E., W.J.M.); and Department of Clinical Biochemistry, Statens Serum Institut, Copenhagen, Denmark (M.C., R.F.-H., P.S.A.)
| | - Petros Syrris
- From the Inherited Cardiovascular Disease Unit, The Heart Hospital, London, United Kingdom (S.P.P., S.K., P.S., P.M.E., W.J.M.); and Department of Clinical Biochemistry, Statens Serum Institut, Copenhagen, Denmark (M.C., R.F.-H., P.S.A.)
| | - Michael Christiansen
- From the Inherited Cardiovascular Disease Unit, The Heart Hospital, London, United Kingdom (S.P.P., S.K., P.S., P.M.E., W.J.M.); and Department of Clinical Biochemistry, Statens Serum Institut, Copenhagen, Denmark (M.C., R.F.-H., P.S.A.)
| | - Rune Frank-Hansen
- From the Inherited Cardiovascular Disease Unit, The Heart Hospital, London, United Kingdom (S.P.P., S.K., P.S., P.M.E., W.J.M.); and Department of Clinical Biochemistry, Statens Serum Institut, Copenhagen, Denmark (M.C., R.F.-H., P.S.A.)
| | - Paal Skytt Andersen
- From the Inherited Cardiovascular Disease Unit, The Heart Hospital, London, United Kingdom (S.P.P., S.K., P.S., P.M.E., W.J.M.); and Department of Clinical Biochemistry, Statens Serum Institut, Copenhagen, Denmark (M.C., R.F.-H., P.S.A.)
| | - Perry M. Elliott
- From the Inherited Cardiovascular Disease Unit, The Heart Hospital, London, United Kingdom (S.P.P., S.K., P.S., P.M.E., W.J.M.); and Department of Clinical Biochemistry, Statens Serum Institut, Copenhagen, Denmark (M.C., R.F.-H., P.S.A.)
| | - William J. McKenna
- From the Inherited Cardiovascular Disease Unit, The Heart Hospital, London, United Kingdom (S.P.P., S.K., P.S., P.M.E., W.J.M.); and Department of Clinical Biochemistry, Statens Serum Institut, Copenhagen, Denmark (M.C., R.F.-H., P.S.A.)
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Otsuka H, Arimura T, Abe T, Kawai H, Aizawa Y, Kubo T, Kitaoka H, Nakamura H, Nakamura K, Okamoto H, Ichida F, Ayusawa M, Nunoda S, Isobe M, Matsuzaki M, Doi YL, Fukuda K, Sasaoka T, Izumi T, Ashizawa N, Kimura A. Prevalence and Distribution of Sarcomeric Gene Mutations in Japanese Patients With Familial Hypertrophic Cardiomyopathy. Circ J 2012; 76:453-461. [DOI: 10.1253/circj.cj-11-0876] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 08/30/2023]
Affiliation(s)
- Haruna Otsuka
- Department of Molecular Pathogenesis, Medical Research Institute, Tokyo Medical and Dental University
| | - Takuro Arimura
- Department of Molecular Pathogenesis, Medical Research Institute, Tokyo Medical and Dental University
| | - Tadaaki Abe
- Department of Pediatric Cardiovascular Medicine, National Cerebral and Cardiovascular Center
| | - Hiroya Kawai
- Division of Cardiovascular Medicine, Department of Internal Medicine, Kobe University Graduate School of Medicine
| | | | - Toru Kubo
- Department of Medicine and Geriatrics, Kochi Medical School
| | | | - Hiroshi Nakamura
- Department of Community Health and Medicine, Yamaguchi University School of Medicine
| | - Kazufumi Nakamura
- Department of Cardiovascular Medicine, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences
| | - Hiroshi Okamoto
- Department of Cardiovascular Medicine, Hokkaido Medical Center
| | - Fukiko Ichida
- Department of Pediatrics, Toyama University School of Medicine
| | - Mamoru Ayusawa
- Department of Pediatrics and Child Health, Nihon University School of Medicine
| | - Shinichi Nunoda
- Cardiovascular Division, Tokyo Women's Medical University Medical Center East
| | - Mitsuaki Isobe
- Department of Cardiovascular Medicine, Graduate School of Medical and Dental Science, Tokyo Medical and Dental University
| | - Masunori Matsuzaki
- Department of Cardiovascular Medicine, Yamaguchi University School of Medicine
| | | | - Keiichi Fukuda
- Department of Cardiology, Keio University School of Medicine
| | - Taishi Sasaoka
- Department of Cardiovascular Medicine, Kitasato University School of Medicine
| | - Toru Izumi
- Department of Cardiovascular Medicine, Kitasato University School of Medicine
| | - Naoto Ashizawa
- Department of Cardiovascular Medicine, Nagasaki University Graduate School of Biomedical Sciences
| | - Akinori Kimura
- Department of Molecular Pathogenesis, Medical Research Institute, Tokyo Medical and Dental University
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8
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Pasquale F, Syrris P, Kaski JP, Mogensen J, McKenna WJ, Elliott P. Long-term outcomes in hypertrophic cardiomyopathy caused by mutations in the cardiac troponin T gene. ACTA ACUST UNITED AC 2011; 5:10-7. [PMID: 22144547 DOI: 10.1161/circgenetics.111.959973] [Citation(s) in RCA: 82] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
BACKGROUND Hypertrophic cardiomyopathy caused by mutations in the cardiac troponin T gene (TNNT2) has been associated with a high risk of sudden cardiac death (SCD) and mild left ventricular hypertrophy. However, previous studies are limited by sample size, cross-sectional design, and few data in relatives. METHODS AND RESULTS Five hundred fifty-two unrelated hypertrophic cardiomyopathy probands were screened for TNNT2 mutations. First-degree relatives were invited for clinical and genetic evaluation. Ninety-two individuals (20 probands and 72 relatives) carried TNNT2 mutations (51 [55%] male; 30±17 years). ECGs and echo were available in 87 (95%) and 88 (96%) individuals, respectively. ECG was normal in 13 (68%) children (<16 years) and 13 (19%) adults. Echo was normal in 18 (90%) children and 16 (24%) adults; 7 (10%) adults had a normal ECG and echo. Thirteen (65%) of 20 families had a history of SCD. Follow-up was available for 75 patients (mean, 9.9±5.2 years); 2 of 16 adults and 2 of 18 children with normal echoes developed left ventricular hypertrophy. Twenty-three (22%) received an implantable cardioverter-defibrillator (20 for primary prophylaxis). One child and 3 adults died of SCD and 2 adults were resuscitated from ventricular fibrillation. One patient had an appropriate implantable cardioverter-defibrillator discharge. The rate of cardiovascular death, transplant, and implantable cardioverter-defibrillator discharge was 1.6% (0.016 person/y; 95% confidence interval, 0.83-2.79%), and SCD 0.93% (0.0093 person/y; 95% confidence interval, 0.37-1.92%). CONCLUSIONS Left ventricular hypertrophy is rare in children with TNNT2 mutations. Left ventricular hypertrophy is absent in the minority of adults, but most have an abnormal ECG. Despite adverse family histories, the rate of cardiovascular death during follow-up was similar to that reported in large referral populations.
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Affiliation(s)
- Ferdinando Pasquale
- Heart Hospital, Institute of Cardiovascular Sciences, University College London, London, United Kingdom
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9
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Devaney JM, Gordish-Dressman H, Harmon BT, Bradbury MK, Devaney SA, Harris TB, Thompson PD, Clarkson PM, Price TB, Angelopoulos TJ, Gordon PM, Moyna NM, Pescatello LS, Visich PS, Zoeller RF, Seip RL, Seo J, Kim BH, Tosi LL, Garcia M, Li R, Zmuda JM, Delmonico MJ, Lindsay RS, Howard BV, Kraus WE, Hoffman EP. AKT1 polymorphisms are associated with risk for metabolic syndrome. Hum Genet 2011; 129:129-39. [PMID: 21061022 PMCID: PMC3020305 DOI: 10.1007/s00439-010-0910-8] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2010] [Accepted: 10/17/2010] [Indexed: 12/31/2022]
Abstract
Converging lines of evidence suggest that AKT1 is a major mediator of the responses to insulin, insulin-like growth factor 1 (IGF1), and glucose. AKT1 also plays a key role in the regulation of both muscle cell hypertrophy and atrophy. We hypothesized that AKT1 variants may play a role in the endophenotypes that make up metabolic syndrome. We studied a 12-kb region including the first exon of the AKT1 gene for association with metabolic syndrome-related phenotypes in four study populations [FAMUSS cohort (n = 574; age 23.7 ± 5.7 years), Strong Heart Study (SHS) (n = 2,134; age 55.5 ± 7.9 years), Dynamics of Health, Aging and Body Composition (Health ABC) (n = 3,075; age 73.6 ± 2.9 years), and Studies of a Targeted Risk Reduction Intervention through Defined Exercise (STRRIDE) (n = 175; age 40–65 years)]. We identified a three SNP haplotype that we call H1, which represents the ancestral alleles at the three loci and H2, which represents the derived alleles at the three loci. In young adult European Americans (FAMUSS), H1 was associated with higher fasting glucose levels in females. In middle age Native Americans (SHS), H1 carriers showed higher fasting insulin and HOMA in males, and higher BMI in females. In older African-American and European American subjects (Health ABC) H1 carriers showed a higher incidence of metabolic syndrome. Homozygotes for the H1 haplotype showed about twice the risk of metabolic syndrome in both males and females (p < 0.001). In middle-aged European Americans with insulin resistance (STRRIDE) studied by intravenous glucose tolerance test (IVGTT), H1 carriers showed increased insulin resistance due to the Sg component (p = 0.021). The 12-kb haplotype is a risk factor for metabolic syndrome and insulin resistance that needs to be explored in further populations.
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Affiliation(s)
- Joseph M. Devaney
- Department of Integrative Systems Biology, Research Center for Genetic Medicine, Children’s National Medical Center, 111 Michigan Ave. NW, Washington, DC, 20010 USA
| | - Heather Gordish-Dressman
- Department of Integrative Systems Biology, Research Center for Genetic Medicine, Children’s National Medical Center, 111 Michigan Ave. NW, Washington, DC, 20010 USA
| | - Brennan T. Harmon
- Department of Integrative Systems Biology, Research Center for Genetic Medicine, Children’s National Medical Center, 111 Michigan Ave. NW, Washington, DC, 20010 USA
| | - Margaret K. Bradbury
- Department of Integrative Systems Biology, Research Center for Genetic Medicine, Children’s National Medical Center, 111 Michigan Ave. NW, Washington, DC, 20010 USA
| | - Stephanie A. Devaney
- Department of Integrative Systems Biology, Research Center for Genetic Medicine, Children’s National Medical Center, 111 Michigan Ave. NW, Washington, DC, 20010 USA
| | - Tamara B. Harris
- National Institute of Aging, National Institutes of Health, Bethesda, MD 20892 USA
| | - Paul D. Thompson
- Division of Cardiology, Henry Low Heart Center, Hartford Hospital, Hartford, CT 06102 USA
| | | | - Thomas B. Price
- Division of Cardiology, Henry Low Heart Center, Hartford Hospital, Hartford, CT 06102 USA
- Department of Diagnostic Radiology, Yale University School of Medicine, New Haven, CT 06520 USA
| | - Theodore J. Angelopoulos
- Department of Health Professions, Center for Lifestyle Medicine, University of Central Florida, Orlando, FL 32816 USA
| | - Paul M. Gordon
- Laboratory for Physical Activity and Exercise Intervention Research, University of Michigan, Ann Arbor, MI 48108 USA
| | - Niall M. Moyna
- Department of Sport Science and Health, Dublin City University, Dublin 9, Ireland
| | | | - Paul S. Visich
- Human Performance Laboratory, Central Michigan University, Mount Pleasant, MI 48859 USA
| | - Robert F. Zoeller
- Department of Exercise Science and Health Promotion, Florida Atlantic University, Davie, FL 33314 USA
| | - Richard L. Seip
- Division of Cardiology, Henry Low Heart Center, Hartford Hospital, Hartford, CT 06102 USA
| | - Jinwook Seo
- Department of Integrative Systems Biology, Research Center for Genetic Medicine, Children’s National Medical Center, 111 Michigan Ave. NW, Washington, DC, 20010 USA
| | | | - Laura L. Tosi
- Orthopedic Surgery and Sports Medicine, Children’s National Medical Center, Washington, DC, 20010 USA
| | - Melissa Garcia
- National Institute of Aging, National Institutes of Health, Bethesda, MD 20892 USA
| | - Rongling Li
- Department of Preventive Medicine, University of Tennessee, Memphis, TN 39163 USA
| | - Joseph M. Zmuda
- Department of Epidemiology and Human Genetics, University of Pittsburgh, Pittsburgh, PA 15261 USA
| | | | | | | | - William E. Kraus
- Duke Center for Living, Duke University Medical Center, Durham, NC 27710 USA
| | - Eric P. Hoffman
- Department of Integrative Systems Biology, Research Center for Genetic Medicine, Children’s National Medical Center, 111 Michigan Ave. NW, Washington, DC, 20010 USA
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Willott RH, Gomes AV, Chang AN, Parvatiyar MS, Pinto JR, Potter JD. Mutations in Troponin that cause HCM, DCM AND RCM: what can we learn about thin filament function? J Mol Cell Cardiol 2009; 48:882-92. [PMID: 19914256 DOI: 10.1016/j.yjmcc.2009.10.031] [Citation(s) in RCA: 154] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/21/2009] [Revised: 10/19/2009] [Accepted: 10/30/2009] [Indexed: 12/25/2022]
Abstract
Troponin (Tn) is a critical regulator of muscle contraction in cardiac muscle. Mutations in Tn subunits are associated with hypertrophic, dilated and restrictive cardiomyopathies. Improved diagnosis of cardiomyopathies as well as intensive investigation of new mouse cardiomyopathy models has significantly enhanced this field of research. Recent investigations have showed that the physiological effects of Tn mutations associated with hypertrophic, dilated and restrictive cardiomyopathies are different. Impaired relaxation is a universal finding of most transgenic models of HCM, predicted directly from the significant changes in Ca(2+) sensitivity of force production. Mutations associated with HCM and RCM show increased Ca(2+) sensitivity of force production while mutations associated with DCM demonstrate decreased Ca(2+) sensitivity of force production. This review spotlights recent advances in our understanding on the role of Tn mutations on ATPase activity, maximal force development and heart function as well as the correlation between the locations of these Tn mutations within the thin filament and myofilament function.
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Affiliation(s)
- Ruth H Willott
- Department of Molecular and Cellular Pharmacology, University of Miami Miller School of Medicine, Miami, FL 33136, USA
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11
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Franchi GM, Villa VV, Carrera P, Sartorio SM, Maffi P, Bosi E, Manzoni MF. A new mutation in the MEN1 gene. ACTA ACUST UNITED AC 2009; 192:99-101. [DOI: 10.1016/j.cancergencyto.2009.04.012] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2009] [Accepted: 04/07/2009] [Indexed: 11/29/2022]
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12
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Mitochondrial DNA analysis by multiplex denaturing high-performance liquid chromatography and selective sequencing in pediatric patients with cardiomyopathy. Genet Med 2009; 11:118-26. [PMID: 19265752 DOI: 10.1097/gim.0b013e318190356b] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
PURPOSE Mitochondrial DNA testing is typically performed by targeted mutation analysis only. We applied a more comprehensive approach to study the mitochondrial genome in 24 pediatric patients with idiopathic cardiomyopathy. METHODS Patients in the cohort did not show overt multisystemic disease and were previously tested for mutations in a subset of structural genes associated with cardiomyopathy. Mutation screening of the mitochondrial DNA by multiplex denaturing high-performance liquid chromatography was complemented by sequence analysis. RESULTS We identified 130 individual (unique) sequence changes. Among several potentially pathogenic changes, a novel heteroplasmic mutation in nicotinamide adenine dinucleotide dehydrogenase subunit 4 (10677G>A) was identified in one fraternal twin with worse clinical symptoms than his sibling. Another proband carried homoplasmic mutation 13708G>A (in nicotinamide adenine dinucleotide dehydrogenase subunit 5) that has been associated with Leber's hereditary optic neuropathy. CONCLUSIONS Changes in mitochondrial DNA may represent a relatively rare cause of idiopathic pediatric cardiomyopathies and/or influence their phenotypic expression. Interpretation of variants with uncertain pathogenicity, however, currently impedes clinical diagnostic use of comprehensive mitochondrial DNA testing. Whereas combined use of multiplex denaturing high-performance liquid chromatography and sequencing is more comprehensive than targeted mutation analysis, measurement of additional functional parameters, such as tissue respiratory chain activity, remains important to establishing a definitive diagnosis.
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Tsuji T, Niida Y. Development of a simple and highly sensitive mutation screening system by enzyme mismatch cleavage with optimized conditions for standard laboratories. Electrophoresis 2008; 29:1473-83. [PMID: 18300207 DOI: 10.1002/elps.200700729] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Efficient screening of unknown DNA variations is one of the substantive matters of molecular biology even today. Historically, SSCP and heteroduplex analysis (HA) are the most commonly used methods for detecting DNA variations everywhere in the world because of their simplicity. However, the sensitivity of these methods is not satisfactory for screening purpose. Recently, several new PCR-based mutation screening methods have been developed, but most of them require special instruments and adjustment of conditions for each DNA sequence to attain the maximum sensitivity, eventually becoming as inconvenient as old methods. Enzyme mismatch cleavage (EMC) is potentially an ideal screening method. With high-performance nucleases and once experimental conditions are optimized, it requires only conventional staff and conditions remain the same for each PCR product. In this study we tested four commercially available endonucleases for EMC and optimized the electrophoresis and developing conditions. We prepared 25 known DNA variations consisting of 18 single base substitutions (8 transitions and 10 transversions, including all possible sets of mismatches) and 7 small deletions or insertions. The combination of CEL nuclease, 12% PAGE and rapid silver staining can detect all types of mutations and achieved 100% sensitivity.
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Affiliation(s)
- Takanori Tsuji
- Department of Pediatrics, Kanazawa University Graduate School of Medical Science, Ishikawa, Japan
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14
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Genetic analysis of hereditary multiple exostoses in Tunisian families: a novel frame-shift mutation in the EXT1 gene. Mol Biol Rep 2008; 36:661-7. [DOI: 10.1007/s11033-008-9226-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2007] [Accepted: 03/05/2008] [Indexed: 11/26/2022]
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15
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Manzoni MF, Franchi GM, Sartorio SM, Di Rosa E, Cappelletti C, Piani C, Cattaneo C, Ferrari M, Bosi E, Carrera P. A novel MEN1 gene mutation. ACTA ACUST UNITED AC 2008; 180:165-7. [DOI: 10.1016/j.cancergencyto.2007.10.017] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2007] [Accepted: 10/22/2007] [Indexed: 10/22/2022]
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16
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Taylor A, Tabrah S, Wang D, Sozen M, Duxbury N, Whittall R, Humphries SE, Norbury G. Multiplex ARMS analysis to detect 13 common mutations in familial hypercholesterolaemia. Clin Genet 2007; 71:561-8. [PMID: 17539906 DOI: 10.1111/j.1399-0004.2007.00807.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
DNA analysis and mutation identification is useful for the diagnosis of familial hypercholesterolaemia (FH), particularly in the young and in other situations where clinical diagnosis may be difficult, and enables unambiguous identification of at-risk relatives. Mutation screening of the whole of the three FH-causing genes is costly and time consuming. We have tested the specificity and sensitivity of a recently developed multiplex amplification refractory mutation system assay of 11 low-density lipoprotein receptor gene (LDLR) mutations, one APOB (p.R3527Q) and one PCSK9 (p.D374Y) mutation in 400 patients attending 10 UK lipid clinics. The kit detected a mutation in 54 (14%) patients, and a complete screen of the LDLR gene using single-stranded conformation polymorphism/denaturing high performance liquid chromatography identified 59 different mutations (11 novel) in an additional 87 patients, for an overall detection rate of 35%. The kit correctly identified 38% of all detected mutations by the full screen, with no false-positive or false-negative results. In the patients with a clinical diagnosis of definite FH, the overall detection rate was higher (54/110 = 49%), with the kit detecting 52% of the full-screen mutations. Results can be obtained within a week of sample receipt, and the high detection rate and good specificity make this a useful initial DNA diagnostic test for UK patients.
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Affiliation(s)
- A Taylor
- Regional Molecular Genetics Laboratory, Great Ormond Street Hospital for Children, Great Ormond Street, London, WC1N 3JH, UK
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17
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Abstract
Over 120 inherited primary immunodeficiency diseases (PIDs) are known to exist. The genes responsible for many of these diseases have also been identified. Recent advances in diagnostic procedures have enabled these to be identified earlier and appropriately treated. While a number of approaches are available to identify mutations, direct sequencing remains the gold standard. This approach identifies the exact genetic change with substantial precision. We suggest that a sensitive and economical approach to mutation detection could be the direct sequencing of cDNA followed by the confirmatory sequencing of the corresponding exon. While screening techniques such as single-stranded conformation polymorphism (SSCP), heteroduplex analysis (HA), denaturing gradient gel electrophoresis (DGGE), and denaturing high-performance liquid chromatography (dHPLC) have proven useful, each has inherent advantages and disadvantages. We discuss these advantages and disadvantages and also discuss the potential of future sequencing technologies such as pyrosequencing, combinatorial sequencing-by-hybridization, multiplex polymerase colony (polony), and resequencing arrays as tools for future mutation detection. In addition we briefly discuss several high-throughput SNP detection technologies.
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Affiliation(s)
- Maurizio Costabile
- School of Pharmacy and Medical Sciences, University of South Australia, Adelaide, Australia.
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18
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Hestekin CN, Barron AE. The potential of electrophoretic mobility shift assays for clinical mutation detection. Electrophoresis 2006; 27:3805-15. [PMID: 17031787 DOI: 10.1002/elps.200600421] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
As the understanding of the links between genetic mutations and diseases continues to grow, there is an increasing need for techniques that can rapidly, inexpensively, and sensitively detect DNA sequence alterations. Typically, such analyses are performed on PCR-amplified gene regions. Automated DNA sequencing by capillary array electrophoresis can be used, but is expensive to apply to large numbers of patient samples and/or large genes, and may not always reveal low-abundance mutations in heterozygous samples. Many different types of genetic differences need to be detected, including single-base substitutions and larger sequence alterations such as insertions, deletions, and inversions. Electrophoretic mobility shift assays seem well suited to this purpose and could be used for the efficient screening of patient samples for sequence alterations, effectively reducing the number of samples that must be subjected to full and careful sequencing. While there is much promise, many of the mobility shift assays presently under development have yet to be demonstrated to have the high sensitivity and specificity of mutation detection required for routine clinical application. Hence, further studies and optimization are required, in particular the application of these methods not only to particular genes but also to large numbers of patient samples in blinded studies aimed at the rigorous determination of sensitivity and specificity. This review examines the state-of-the-art of the most commonly used mobility shift assays for mutation detection, including denaturing gradient gel electrophoresis, TGGE, SSCP, heteroduplex analysis, and denaturing HPLC.
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Affiliation(s)
- Christa N Hestekin
- Department of Chemical and Biological Engineering, Northwestern University, Evanston, IL, USA
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Li W, Gao F, Tang W, Zhang X, Zhang H. Detection of known thalassemia point mutations by snapback single-strand conformation polymorphism: the feasibility analysis. Clin Biochem 2006; 39:833-42. [PMID: 16820146 DOI: 10.1016/j.clinbiochem.2006.05.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2006] [Revised: 04/06/2006] [Accepted: 05/19/2006] [Indexed: 10/24/2022]
Abstract
OBJECTIVES To explore if snapback single-strand conformation polymorphism (snapback SSCP) can be applied to the detection of known thalassemia point mutations. DESIGN AND METHODS We examined 13 types of known thalassemia point mutations by using snapback SSCP. RESULTS These 13 different thalassemia point mutations could be identified by snapback SSCP. CONCLUSIONS Snapback SSCP can be applied to the detection of known thalassemia point mutations. The advantages of snapback SSCP are (1) it is simple as compared to PCR-ASO; (2) snapback SSCP is specific and stable once the conditions of snapback SSCP are optimized; (3) samples can be checked at any time without the limit of half-life of radioactive isotope; and (4) since PCR products used in snapback SSCP can be checked by using 2% agarose gel before snapback SSCP, misdiagnoses caused by false positive or false negative PCR can be reduced significantly in snapback SSCP.
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Affiliation(s)
- Wei Li
- Medical Science Research Center, Guangxi Medical University, and Department of Anal and Colorectal Surgery, The First Affiliated Hospital of Guangxi Medical University, PR China.
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20
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Humphries SE, Cranston T, Allen M, Middleton-Price H, Fernandez MC, Senior V, Hawe E, Iversen A, Wray R, Crook MA, Wierzbicki AS. Mutational analysis in UK patients with a clinical diagnosis of familial hypercholesterolaemia: relationship with plasma lipid traits, heart disease risk and utility in relative tracing. J Mol Med (Berl) 2005; 84:203-14. [PMID: 16389549 DOI: 10.1007/s00109-005-0019-z] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2005] [Accepted: 10/13/2005] [Indexed: 11/25/2022]
Abstract
As part of a randomised trial [Genetic Risk Assessment for Familial Hypercholesterolaemia (FH) Trial] of the psychological consequences of DNA-based and non-DNA-based diagnosis of FH, 338 probands with a clinical diagnosis of FH (46% with tendon xanthomas) were recruited. In the DNA-based testing arm (245 probands), using single-strand conformation polymorphism of all exons of the low-density lipoprotein receptor (LDLR) gene, 48 different pathogenic mutations were found in 62 probands (25%), while 7 (2.9%) of the patients had the R3500Q mutation in the apolipoprotein B (APOB) gene. Compared to those with no detected mutation, mean untreated cholesterol levels in those with the APOB mutation were similar, while in those with an LDLR mutation levels were significantly higher (None=9.15+/-1.62 vs LDLR=9.13+/-1.16 vs APOB=10.26+/-2.07 mmol/l p<0.001, respectively). Thirty seven percent of the detected mutations were in exon 3/4 of LDLR, and this group had significantly higher untreated cholesterol than those with other LDLR mutations (11.71+/-2.39 mmol/l vs 9.88+/-2.44 mmol/l, p=0.03), and more evidence of coronary disease compared to those with other LDLR or APOB mutations (36 vs 13% p=0.04). Of the probands with a detected mutation, 54 first-degree relatives were identified, of whom 27 (50%) had a mutation. Of these, 18 had untreated cholesterol above the 95th percentile for their age and gender, but there was overlap with levels in the non-carrier relatives such that 12% of subjects would have been incorrectly diagnosed on lipid levels alone. In the non-DNA-based testing arm (82 probands) only 19 of the 74 relatives identified had untreated cholesterol above the 95th percentile for their age and gender, which was significantly lower (p<0.0005) than the 50% expected for monogenic inheritance. These data confirm the genetic heterogeneity of LDLR mutations in the UK and the deleterious effect of mutations in exon 3 or 4 of LDLR on receptor function, lipids and severity of coronary heart disease. In patients with a clinical diagnosis of FH but no detectable mutation, there is weaker evidence for a monogenic cause compared with relatives of probands with LDLR mutations. This supports the usefulness of DNA testing to confirm diagnosis of FH for the treatment of hyperlipidaemia and for further cascade screening.
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Affiliation(s)
- Steve E Humphries
- Centre for Cardiovascular Genetics, British Heart Foundation Laboratories, Royal Free and University College London Medical School, Rayne Building, 5 University Street, London WC1E 6JJ, UK.
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21
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Rolfs A, Böttcher T, Zschiesche M, Morris P, Winchester B, Bauer P, Walter U, Mix E, Löhr M, Harzer K, Strauss U, Pahnke J, Grossmann A, Benecke R. Prevalence of Fabry disease in patients with cryptogenic stroke: a prospective study. Lancet 2005; 366:1794-6. [PMID: 16298216 DOI: 10.1016/s0140-6736(05)67635-0] [Citation(s) in RCA: 281] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
BACKGROUND Strokes are an important cause of morbidity and mortality in young adults. However, in most cases the cause of the stroke remains unclear. Anderson-Fabry disease is an X-linked recessive lysosomal storage disease resulting from deficient alpha-galactosidase and causes an endothelial vasculopathy followed by cerebral ischaemia. To determine the importance of Fabry disease in young people with stroke, we measured the frequency of unrecognised Fabry disease in a cohort of acute stroke patients. METHODS Between February, 2001, and December, 2004, 721 German adults aged 18 to 55 years suffering from acute cryptogenic stroke were screened for Fabry disease. The plasma alpha-galactosidase activity in men was measured followed by sequencing of the entire alpha-GAL gene in those with low enzyme activity. By contrast, the entire alpha-GAL gene was genetically screened for mutations in women even if enzyme activity was normal. FINDINGS 21 of 432 (4.9%) male stroke patients and seven of 289 (2.4%) women had a biologically significant mutation within the alpha-GAL gene. The mean age at onset of symptomatic cerebrovascular disease was 38.4 years (SD 13.0) in the male stroke patients and 40.3 years (13.1) in the female group. The higher frequency of infarctions in the vertebrobasilar area correlated with more pronounced changes in the vertebrobasilar vessels like dolichoectatic pathology (42.9%vs 6.8%). INTERPRETATION We have shown a high frequency of Fabry disease in a cohort of patients with cryptogenic stroke, which corresponds to about 1.2% in young stroke patients. Fabry disease must be considered in all cases of unexplained stroke in young patients, especially in those with the combination of infarction in the vertebrobasilar artery system and proteinuria.
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Affiliation(s)
- Arndt Rolfs
- Department of Neurology, University of Rostock, Rostock, Germany.
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22
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Moon JC, Mogensen J, Elliott PM, Smith GC, Elkington AG, Prasad SK, Pennell DJ, McKenna WJ. Myocardial late gadolinium enhancement cardiovascular magnetic resonance in hypertrophic cardiomyopathy caused by mutations in troponin I. Heart 2005; 91:1036-40. [PMID: 16020591 PMCID: PMC1769031 DOI: 10.1136/hrt.2004.041384] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
OBJECTIVE To examine the influence of genotype on late gadolinium enhancement (LGE) and the potential of cardiovascular magnetic resonance (CMR) to detect preclinical hypertrophic cardiomyopathy. DESIGN Prospective, blinded cohort study of myocardial LGE in a genetically homogeneous population. PATIENTS 30 patients with disease causing mutations in the recognised hypertrophic cardiomyopathy gene for cardiac troponin I (TNNI3): 15 with echocardiographically determined left ventricular hypertrophy (LVH+) and 15 without (LVH-). MAIN OUTCOME MEASURES CMR measures of regional left ventricular function, wall thickness, and mass, and the extent and distribution of LGE. RESULTS LGE was found in 12 (80%) LVH+ patients but with variable extent (mean 15%, range 3-48%). LGE was also found in two (13%) LVH- patients but the extent was limited (3.6%) and both patients were found to have an abnormal ECG and regional hypertrophy by cine CMR. The extent of LGE was positively associated with clinical markers of sudden death risk (21% with > or = 2 risk factors v 7% with < or = 1 risk factor, p = 0.02) and left ventricular mass (r = 0.56, p < 0.001) and was inversely associated with ejection fraction (r = -0.58, p < 0.001). Segmental analysis showed that as regional wall thickness increased, LGE was more prevalent (p < 0.0001) and more extensive (r = 0.98, p = 0.001). CONCLUSION In patients with disease causing mutations in TNNI3, focal fibrosis was not detected by LGE CMR before LVH and ECG abnormalities were present. Once LVH is present, LGE is common and the extent correlates with adverse clinical parameters. This suggests that focal fibrosis is closely linked to disease development.
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Affiliation(s)
- J C Moon
- Centre for Advanced Magnetic Resonance in Cardiology, Royal Brompton Hospital, London, UK
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23
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Murphy RT, Mogensen J, McGarry K, Bahl A, Evans A, Osman E, Syrris P, Gorman G, Farrell M, Holton JL, Hanna MG, Hughes S, Elliott PM, Macrae CA, McKenna WJ. Adenosine monophosphate-activated protein kinase disease mimicks hypertrophic cardiomyopathy and Wolff-Parkinson-White syndrome: natural history. J Am Coll Cardiol 2005; 45:922-30. [PMID: 15766830 DOI: 10.1016/j.jacc.2004.11.053] [Citation(s) in RCA: 87] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/14/2004] [Revised: 10/18/2004] [Accepted: 11/22/2004] [Indexed: 10/25/2022]
Abstract
OBJECTIVES The aim of this study was to investigate the clinical expression of adenosine monophosphate-activated protein kinase (AMPK) gene mutations (PRKAG2) in adenosine monophosphate (AMP) kinase disease based on 12 years follow-up of known mutation carriers and to define the prevalence of PRKAG2 mutations in hypertrophic cardiomyopathy (HCM). BACKGROUND Adenosine monophosphate-activated protein kinase gene mutations cause HCM with Wolff-Parkinson-White syndrome and conduction disease. METHODS Clinical evaluation of 44 patients with known AMP kinase disease was analyzed. Mutation analysis of PRKAG2 was performed by fluorescent single-strand confirmation polymorphism analysis and direct sequencing of abnormal conformers in 200 patients with HCM. RESULTS Only one additional mutation was identified. The mean age at clinical diagnosis in the 45 gene carriers was 24 years (median 20 years, range 9 to 55 years). Symptoms of palpitation, dypspnea, chest pain, or syncope were present in 31 (69%) gene carriers; 7 (15%) complained of myalgia and had clinical evidence of proximal myopathy. Skeletal muscle biopsy showed excess mitochondria and ragged red fibers with minimal glycogen accumulation. Disease penetrance defined by typical electrocardiogram abnormalities was 100% by age 18 years. Thirty-two of 41 adults (78%) had left ventricular hypertrophy (LVH) on echocardiography, and progressive LVH was documented during follow-up. Survival was 91% at a mean follow-up of 12.2 years. Progressive conduction disease required pacemaker implantation in 17 of 45 (38%) at a mean age of 38 years. CONCLUSIONS The AMP kinase disease is uncommon in HCM and is characterized by progressive conduction disease and cardiac hypertrophy and includes extracardiac manifestations such as a skeletal myopathy, consistent with a systemic metabolic storage disease. Defects in adenosine triphosphate utilization or in specific cellular substrates, rather than mere passive deposition of amylopectin, may account for these clinical features.
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MESH Headings
- AMP-Activated Protein Kinases
- Adolescent
- Adult
- Cardiomyopathy, Hypertrophic/diagnosis
- Cardiomyopathy, Hypertrophic/enzymology
- Cardiomyopathy, Hypertrophic/therapy
- Child
- Child, Preschool
- Defibrillators, Implantable
- Diagnosis, Differential
- Echocardiography
- Electrocardiography, Ambulatory
- Electrophysiologic Techniques, Cardiac
- Exercise Tolerance/physiology
- Family Health
- Female
- Follow-Up Studies
- Genetic Predisposition to Disease/genetics
- Heart Conduction System/diagnostic imaging
- Heart Conduction System/pathology
- Heart Conduction System/physiopathology
- Humans
- Male
- Middle Aged
- Multienzyme Complexes/genetics
- Multienzyme Complexes/metabolism
- Muscle, Skeletal/diagnostic imaging
- Muscle, Skeletal/pathology
- Muscle, Skeletal/physiopathology
- Mutation/genetics
- Protein Serine-Threonine Kinases/genetics
- Protein Serine-Threonine Kinases/metabolism
- Treatment Outcome
- Wolff-Parkinson-White Syndrome/diagnosis
- Wolff-Parkinson-White Syndrome/enzymology
- Wolff-Parkinson-White Syndrome/therapy
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Affiliation(s)
- Ross T Murphy
- The Heart Hospital, University College London, London, United Kingdom
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24
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Abstract
Troponin, one of the sarcomeric proteins, plays a central role in the Ca(2+) regulation of contraction in vertebrate skeletal and cardiac muscles. It consists of three subunits with distinct structure and function, troponin T, troponin I, and troponin C, and their accurate and complex intermolecular interaction in response to the rapid rise and fall of Ca(2+) in cardiomyocytes plays a key role in maintaining the normal cardiac pump function. More than 200 mutations in the cardiac sarcomeric proteins, including myosin heavy and light chains, actin, troponin, tropomyosin, myosin-binding protein-C, and titin/connectin, have been found to cause various types of cardiomyopathy in human since 1990, and more than 60 mutations in human cardiac troponin subunits have been identified in dilated, hypertrophic, and restrictive forms of cardiomyopathy. In this review, we have focused on the mutations in the genes for human cardiac troponin subunits and discussed their functional consequences that might be involved in the primary mechanisms for the pathogenesis of these different types of cardiomyopathy.
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Affiliation(s)
- K Harada
- Department of Clinical Pharmacology, Kyushu University Graduate School of Medicine, Higashi-ku, Fukuoka 812-8582, Japan
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25
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Abstract
OBJECTIVE To determine the clinical parameters of hypertrophic cardiomyopathy (HCM) that correlated significantly with the presence of an identifiable sarcomeric mutation. PATIENTS AND METHODS Previous comprehensive mutational analyses of all protein-coding exons of 8 sarcomeric genes revealed pathogenic mutations in 147 (38%) of 389 unrelated patients seen at the HCM outpatient clinic at the Mayo Clinic in Rochester, Minn, between April 1997 and December 2001. Clinical data, extracted from patient records and blinded to patient genotype, were maintained in a custom database. RESULTS In 389 unrelated patients, younger age at diagnosis, family history of HCM, and Increasing left ventricular wall thickness were all associated with Increased likelihood of identifying an HCM-associated sarcomeric mutation. In contrast, family history of sudden cardiac death, myectomy status, and anatomical subtype did not correlate significantly with genotype-positive status. With use of a simple scoring system based on age at diagnosis, left ventricular wall thickness, and family history of HCM, the likelihood of a sarcomeric mutation could be estimated. CONCLUSION Clinical predictors of positive genotype, such as the presence of an implantable cardioverter-defibrillator, age at diagnosis, degree of left ventricular wall hypertrophy, and family history of HCM, may aid in patient selection for genetic testing and increase the yield of cardiac sarcomere gene screening.
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Affiliation(s)
- Sara L Van Driest
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic College of Medicine, Rochester, MN 55905, USA
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Palmen J, Colhoun HM, Van Tol A, Hattori H, Humphries SE. A novel common variant −181 G insertion in the promoter of the gene for phospholipid transfer protein. Atherosclerosis 2005; 180:211-3. [PMID: 15823296 DOI: 10.1016/j.atherosclerosis.2004.12.027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/04/2004] [Revised: 11/29/2004] [Accepted: 12/03/2004] [Indexed: 11/25/2022]
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Van Driest SL, Vasile VC, Ommen SR, Will ML, Tajik AJ, Gersh BJ, Ackerman MJ. Myosin binding protein C mutations and compound heterozygosity in hypertrophic cardiomyopathy. J Am Coll Cardiol 2005; 44:1903-10. [PMID: 15519027 DOI: 10.1016/j.jacc.2004.07.045] [Citation(s) in RCA: 318] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/23/2004] [Revised: 06/25/2004] [Accepted: 07/28/2004] [Indexed: 12/11/2022]
Abstract
OBJECTIVES We sought to determine the frequency and phenotype of mutations in myosin binding protein C (MYBPC3) in a large outpatient cohort of patients with hypertrophic cardiomyopathy (HCM) seen at our tertiary referral center. BACKGROUND Mutations in MYBPC3 are one of the most frequent genetic causes of HCM and have been associated with variable onset of disease and prognosis. However, the frequency of mutations and associated clinical presentation have not been established in a large, unrelated cohort of patients. METHODS Using deoxyribonucleic acid from 389 unrelated patients with HCM, each protein coding exon of MYBPC3 was analyzed for mutations by polymerase chain reaction, denaturing high-performance liquid chromatography, and direct deoxyribonucleic acid sequencing. Clinical data were extracted from patient records blinded to patient genotype. RESULTS Of 389 patients with HCM, 71 (18%) had mutations in MYBPC3. In all, 46 mutations were identified, 33 of which were novel (72%). Patients with MYBPC3 mutations did not differ significantly from patients with thick filament-HCM, thin filament-HCM, or genotype-negative HCM with respect to age at diagnosis, degree of hypertrophy, incidence of myectomy, or family history of HCM or sudden death. Patients with multiple mutations (n = 10, 2.6%) had the most severe disease presentation. CONCLUSIONS This study defines the frequency and associated phenotype for MYBPC3 and/or multiple mutations in HCM in the largest cohort to date. In this cohort, unrelated patients with MYBPC3-HCM virtually mimicked the phenotype of those with mutations in the beta-myosin heavy chain. Patients with multiple mutations had the most severe phenotype.
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Affiliation(s)
- Sara L Van Driest
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic College of Medicine, Rochester, Minnesota, USA
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28
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Mogensen J, Murphy RT, Kubo T, Bahl A, Moon JC, Klausen IC, Elliott PM, McKenna WJ. Frequency and clinical expression of cardiac troponin I mutations in 748 consecutive families with hypertrophic cardiomyopathy. J Am Coll Cardiol 2004; 44:2315-25. [PMID: 15607392 DOI: 10.1016/j.jacc.2004.05.088] [Citation(s) in RCA: 93] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/20/2004] [Accepted: 05/04/2004] [Indexed: 11/19/2022]
Abstract
OBJECTIVES The aim of this study was to evaluate the potential utility of genetic diagnosis in clinical management of families with hypertrophic cardiomyopathy (HCM) caused by mutations in the gene for cardiac troponin I (TNNI3). BACKGROUND Knowledge about the clinical disease expression of sarcomeric gene mutations in HCM has predominantly been obtained by investigations of single individuals (probands) or selected families. To establish the role of genetic diagnosis in HCM families, systematic investigations of probands and their relatives are needed. METHODS Cardiac troponin I was investigated by direct sequencing and fluorescent (F)-SSCP analysis in 748 consecutive HCM families. Relatives of HCM probands with TNNI3 mutations were invited for cardiovascular and genetic assessment. RESULTS The prevalence of TNNI3 mutations was 3.1%. Mutations appeared to cluster in exons 7 and 8. A total of 100 mutation carriers were identified in 23 families with 13 different mutations (6 novel). Disease penetrance was 48%. Patients were diagnosed from the second to eighth decade of life. The morphologic spectrum observed represented a wide range of HCM. Two offspring of clinically unaffected mutation carriers were resuscitated from cardiac arrest, and an additional four individuals died suddenly as their initial presentation. Six individuals experienced other disease-related deaths. CONCLUSIONS The clinical expression of TNNI3 mutations was very heterogeneous and varied both within and between families with no apparent mutation- or gene-specific disease pattern. The data suggest that disease development may be monitored by regular assessment of cardiac symptoms and electrocardiographic abnormalities. Genetic diagnosis of TNNI3 is valuable in identifying clinically unaffected mutation carriers at risk of disease development and facilitates accurate management and counseling.
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Affiliation(s)
- Jens Mogensen
- Department of Cardiological Sciences, St. George's Hospital Medical School, London, United Kingdom.
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29
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Sozen M, Whittall R, Humphries SE. Mutation detection in patients with familial hypercholesterolaemia using heteroduplex and single strand conformation polymorphism analysis by capillary electrophoresis. ATHEROSCLEROSIS SUPP 2004; 5:7-11. [PMID: 15556093 DOI: 10.1016/j.atherosclerosissup.2004.09.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Mutations in the low-density lipoprotein receptor (LDLR) gene give rise to familial hypercholesterolaemia (FH). In this study we have used a 96-well capillary machine (MegaBACE, Amersham) to develop a single strand conformation polymorphism (SSCP) and heteroduplex method for the detection of mutations in the LDLR gene. We have applied this technique to 101 different mutations including single nucleotide polymorphisms in different exons of the LDLR gene. Hundred percent of these nucleotide alterations were distinguished by this method. We suggest this fast, reliable and safe method for diagnosis of FH in large patient groups.
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Affiliation(s)
- Mert Sozen
- Department of Biology, Faculty of Science, Molecular Biology Section, Hacettepe University, Beytepe, Ankara, Turkey
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30
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Severe disease expression of cardiac troponin C and T mutations in patients with idiopathic dilated cardiomyopathy. J Am Coll Cardiol 2004; 44:2033-40. [DOI: 10.1016/j.jacc.2004.08.027] [Citation(s) in RCA: 191] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/22/2004] [Revised: 07/29/2004] [Accepted: 08/03/2004] [Indexed: 11/23/2022]
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Balogh K, Patócs A, Majnik J, Rácz K, Hunyady L. Genetic screening methods for the detection of mutations responsible for multiple endocrine neoplasia type 1. Mol Genet Metab 2004; 83:74-81. [PMID: 15464422 DOI: 10.1016/j.ymgme.2004.08.013] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/30/2004] [Accepted: 08/31/2004] [Indexed: 11/24/2022]
Abstract
Identification of mutations, which cause genetic diseases can be difficult when the disease is caused by the mutation of a large gene, which contains multiple exons. Detection of these mutations by DNA sequencing can be made more efficient by using mutation detection methods for pre-screening to identify the affected exon and to screen for the presence of already identified mutations in family members. These screening methods include denaturing gradient gel electrophoresis (DGGE), temperature gradient gel electrophoresis (TGGE), single-strand conformation polymorphism, conformation-sensitive gel electrophoresis (CSGE), heteroduplex analysis and denaturing high-performance liquid chromatography (DHPLC). We discuss the advantages and shortcomings of these methods by reviewing the results of studies screening for mutations causing multiple endocrine neoplasia type 1 (MEN 1) syndrome, an autosomal dominant disorder characterized by endocrine tumours of the anterior pituitary gland, parathyroid glands, and pancreas. MEN 1 is caused by mutations of the MEN1 gene, a tumour suppressor gene, which contains one untranslated exon and nine exons. Previous studies have identified more than 400 germline and somatic mutations spreading across all the encoding sequence, and found no mutational "hot spot" or genotype-phenotype correlation. The wide diversity of mutations in the entire coding region of the MEN1 gene makes mutation screening time-consuming and expensive. We conclude that combination of mutation detection methods with DNA sequencing enhances the efficiency of identifying pathogenic mutations. However, it should be considered that experimental determination of the optimal electrophoresis conditions, such as using perpendicular electrophoresis to optimise DGGE or TGGE, is more useful than computerized algorithms to calculate these parameters.
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Affiliation(s)
- Katalin Balogh
- 2nd Department of Medicine, Faculty of Medicine, Semmelweis University, Budapest, Hungary
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Van Driest SL, Jaeger MA, Ommen SR, Will ML, Gersh BJ, Tajik AJ, Ackerman MJ. Comprehensive Analysis of the Beta-Myosin Heavy Chain Gene in 389 Unrelated Patients With Hypertrophic Cardiomyopathy. J Am Coll Cardiol 2004; 44:602-10. [PMID: 15358028 DOI: 10.1016/j.jacc.2004.04.039] [Citation(s) in RCA: 140] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/04/2003] [Revised: 03/18/2004] [Accepted: 04/13/2004] [Indexed: 11/30/2022]
Abstract
OBJECTIVES We sought to determine the prevalence and phenotype of beta-myosin heavy chain gene MYH7 mutations in a large cohort of unrelated patients with hypertrophic cardiomyopathy (HCM). BACKGROUND Hypertrophic cardiomyopathy is a heterogeneous cardiac disease. MYH7 mutations are one of the most common genetic causes of HCM and have been associated with severe hypertrophy, young age of diagnosis, and high risk of sudden cardiac death. However, these clinical findings from large, family studies have not been confirmed in a large unrelated cohort. METHODS Deoxyribonucleic (DNA) samples obtained from 389 HCM outpatients seen at this tertiary referral center were analyzed for mutations, using polymerase chain reaction, denaturing high-performance liquid chromatography, and DNA sequencing for all 38 protein-coding exons of MYH7. Clinical data were extracted from patient records blinded to patient genotype. RESULTS Fifty-eight patients (15%) harbored 40 different mutations in MYH7. Compared with HCM patients without MYH7 mutations, HCM patients with MYH7 were younger at diagnosis (32.9 vs. 42.7 years, p = 0.0002), had more hypertrophy (left ventricular wall thickness of 24.2 vs. 21.1 mm, p = 0.0009), and more frequently underwent myectomy (60% vs. 38%, p = 0.002). The HCM patients with MYH7 mutations more often had a family history of HCM (43% vs. 29%, p = 0.006), but there was no difference in family history of sudden death (16% vs. 14%, p = NS). CONCLUSIONS In this setting, HCM patients with MYH7 were diagnosed at a younger age and had more hypertrophy, but they had no greater frequency of sudden death among first-degree relatives. Although these associations may prove useful for targeted gene screening, caution should be exercised in terms of using pathogenic status in risk stratification.
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Affiliation(s)
- Sara L Van Driest
- Departments of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic College of Medicine, Rochester, Minnesota, USA
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Murphy RT, Mogensen J, Shaw A, Kubo T, Hughes S, McKenna WJ. Novel mutation in cardiac troponin I in recessive idiopathic dilated cardiomyopathy. Lancet 2004; 363:371-2. [PMID: 15070570 DOI: 10.1016/s0140-6736(04)15468-8] [Citation(s) in RCA: 113] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Idiopathic dilated cardiomyopathy is a common cause of heart failure. Half of cases are believed to be hereditary, and mutations in cardiac sarcomeric contractile protein genes have been reported with autosomal dominant inheritance. We used mutation analysis suitable for identification of both dominant and recessive mutations to investigate the sarcomeric gene for cardiac troponin I (TNNI3) in 235 patients with dilated cardiomyopathy. We identified a novel TNNI3 mutation in a family with recessive disease. Functional studies showed impairment of troponin interactions that could lead to diminished myocardial contractility. TNNI3 is the first recessive gene identified for this condition, and we suggest that other such genes could be pinpointed by mutation analyses designed to identify homozygous mutations.
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Affiliation(s)
- Ross T Murphy
- Department of Cardiological Sciences, St George's Hospital Medical School, London, UK
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