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EFHC1 variants in juvenile myoclonic epilepsy: reanalysis according to NHGRI and ACMG guidelines for assigning disease causality. Genet Med 2016; 19:144-156. [PMID: 27467453 DOI: 10.1038/gim.2016.86] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2015] [Accepted: 05/09/2016] [Indexed: 12/12/2022] Open
Abstract
PURPOSE EFHC1 variants are the most common mutations in inherited myoclonic and grand mal clonic-tonic-clonic (CTC) convulsions of juvenile myoclonic epilepsy (JME). We reanalyzed 54 EFHC1 variants associated with epilepsy from 17 cohorts based on National Human Genome Research Institute (NHGRI) and American College of Medical Genetics and Genomics (ACMG) guidelines for interpretation of sequence variants. METHODS We calculated Bayesian LOD scores for variants in coinheritance, unconditional exact tests and odds ratios (OR) in case-control associations, allele frequencies in genome databases, and predictions for conservation/pathogenicity. We reviewed whether variants damage EFHC1 functions, whether efhc1-/- KO mice recapitulate CTC convulsions and "microdysgenesis" neuropathology, and whether supernumerary synaptic and dendritic phenotypes can be rescued in the fly model when EFHC1 is overexpressed. We rated strengths of evidence and applied ACMG combinatorial criteria for classifying variants. RESULTS Nine variants were classified as "pathogenic," 14 as "likely pathogenic," 9 as "benign," and 2 as "likely benign." Twenty variants of unknown significance had an insufficient number of ancestry-matched controls, but ORs exceeded 5 when compared with racial/ethnic-matched Exome Aggregation Consortium (ExAC) controls. CONCLUSIONS NHGRI gene-level evidence and variant-level evidence establish EFHC1 as the first non-ion channel microtubule-associated protein whose mutations disturb R-type VDCC and TRPM2 calcium currents in overgrown synapses and dendrites within abnormally migrated dislocated neurons, thus explaining CTC convulsions and "microdysgenesis" neuropathology of JME.Genet Med 19 2, 144-156.
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Sampson MG, Gillies CE, Robertson CC, Crawford B, Vega-Warner V, Otto EA, Kretzler M, Kang HM. Using Population Genetics to Interrogate the Monogenic Nephrotic Syndrome Diagnosis in a Case Cohort. J Am Soc Nephrol 2016; 27:1970-83. [PMID: 26534921 PMCID: PMC4926977 DOI: 10.1681/asn.2015050504] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2015] [Accepted: 09/06/2015] [Indexed: 01/02/2023] Open
Abstract
To maximize clinical benefits of genetic screening of patients with nephrotic syndrome (NS) to diagnose monogenic causes, reliably distinguishing NS-causing variants from the background of rare, noncausal variants prevalent in all genomes is vital. To determine the prevalence of monogenic NS in a North American case cohort while accounting for background prevalence of genetic variation, we sequenced 21 implicated monogenic NS genes in 312 participants from the Nephrotic Syndrome Study Network and 61 putative controls from the 1000 Genomes Project (1000G). These analyses were extended to available sequence data from approximately 2500 subjects from the 1000G. A typical pathogenicity filter identified causal variants for NS in 4.2% of patients and 5.8% of subjects from the 1000G. We devised a more stringent pathogenicity filtering strategy, reducing background prevalence of causal variants to 1.5%. When applying this stringent filter to patients, prevalence of monogenic NS was 2.9%; of these patients, 67% were pediatric, and 44% had FSGS on biopsy. The rate of complete remission did not associate with monogenic classification. Thus, we identified factors contributing to inaccurate monogenic classification of NS and developed a more accurate variant filtering strategy. The prevalence and clinical correlates of monogenic NS in this sporadically affected cohort differ substantially from those reported for patients referred for genetic analysis. Particularly in unselected, population-based cases, considering putative causal variants in known NS genes from a probabilistic rather than a deterministic perspective may be more precise. We also introduce GeneVetter, a web tool for monogenic assessment of rare disease.
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Affiliation(s)
| | | | | | | | | | - Edgar A Otto
- Departments of Pediatrics and Communicable Diseases, and
| | - Matthias Kretzler
- Internal Medicine, Division of Nephrology and Department of Computational Medicine and Bioinformatics, University of Michigan School of Medicine, Ann Arbor, Michigan; and
| | - Hyun Min Kang
- Department of Biostatistics, University of Michigan School of Public Health, Ann Arbor, Michigan
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Perrot A, Tomasov P, Villard E, Faludi R, Melacini P, Lossie J, Lohmann N, Richard P, De Bortoli M, Angelini A, Varga-Szemes A, Sperling SR, Simor T, Veselka J, Özcelik C, Charron P. Mutations in NEBL encoding the cardiac Z-disk protein nebulette are associated with various cardiomyopathies. Arch Med Sci 2016; 12:263-78. [PMID: 27186169 PMCID: PMC4848357 DOI: 10.5114/aoms.2016.59250] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/04/2015] [Accepted: 04/29/2015] [Indexed: 11/17/2022] Open
Abstract
INTRODUCTION Transgenic mice overexpressing mutated NEBL, encoding the cardiac-specific Z-disk protein nebulette, develop severe cardiac phenotypes. Since cardiomyopathies are commonly familial and because mutations in a single gene may result in variable phenotypes, we tested the hypothesis that NEBL mutations are associated with cardiomyopathy. MATERIAL AND METHODS We analyzed 389 patients, including cohorts of patients with dilated cardiomyopathy (DCM), hypertrophic cardiomyopathy (HCM), and left ventricular non-compaction cardiomyopathy (LVNC). The 28 coding exons of the NEBL gene were sequenced. Further bioinformatic analysis was used to distinguish variants. RESULTS In total, we identified six very rare heterozygous missense mutations in NEBL in 7 different patients (frequency 1.8%) in highly conserved codons. The mutations were not detectable in 320 Caucasian sex-matched unrelated individuals without cardiomyopathy and 192 Caucasian sex-matched blood donors without heart disease. Known cardiomyopathy genes were excluded in these patients. The mutations p.H171R and p.I652L were found in 2 HCM patients. Further, p.Q581R and p.S747L were detected in 2 DCM patients, while the mutation p.A175T was identified independently in two unrelated patients with DCM. One LVNC patient carried the mutation p.P916L. All HCM and DCM related mutations were located in the nebulin-like repeats, domains responsible for actin binding. Interestingly, the mutation associated with LVNC was located in the C-terminal serine-rich linker region. CONCLUSIONS Our data suggest that NEBL mutations may cause various cardiomyopathies. We herein describe the first NEBL mutations in HCM and LVNC. Our findings underline the notion that the cardiomyopathies are true allelic diseases.
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Affiliation(s)
- Andreas Perrot
- Charité-Universitätsmedizin Berlin, Cardiovascular Genetics, Experimental and Clinical Research Center, Berlin, Germany
| | - Pavol Tomasov
- Department of Cardiology, 2 Medical School, Charles University, University Hospital Motol, Prague, Czech Republic
| | - Eric Villard
- AP-HP, Département de Génétique et Département de Cardiologie et Inserm UMR 1166, Hopital Pitié-Salpêtrière, Paris, France
| | - Reka Faludi
- Heart Institute, Faculty of Medicine, University of Pécs, Pécs, Hungary
| | - Paola Melacini
- Department of Cardiac, Thoracic and Vascular Sciences, University of Padova, Padova, Italy
| | - Janine Lossie
- Charité-Universitätsmedizin Berlin, Cardiovascular Genetics, Experimental and Clinical Research Center, Berlin, Germany
| | - Nadine Lohmann
- Charité-Universitätsmedizin Berlin, Cardiovascular Genetics, Experimental and Clinical Research Center, Berlin, Germany
| | - Pascale Richard
- Assistance Publique-Hôpitaux de Paris, Groupe Hospitalier Pitié-Salpêtrière, UF Cardiogénétique et Myogénétique, Service de Biochimie Métabolique, Paris, France
| | - Marzia De Bortoli
- Department of Cardiac, Thoracic and Vascular Sciences, University of Padova, Padova, Italy
| | - Annalisa Angelini
- Department of Cardiac, Thoracic and Vascular Sciences, University of Padova, Padova, Italy
| | - Akos Varga-Szemes
- Heart Institute, Faculty of Medicine, University of Pécs, Pécs, Hungary
| | - Silke R. Sperling
- Charité-Universitätsmedizin Berlin, Cardiovascular Genetics, Experimental and Clinical Research Center, Berlin, Germany
| | - Tamás Simor
- Heart Institute, Faculty of Medicine, University of Pécs, Pécs, Hungary
| | - Josef Veselka
- Department of Cardiology, 2 Medical School, Charles University, University Hospital Motol, Prague, Czech Republic
| | - Cemil Özcelik
- Charité-Universitätsmedizin Berlin, Cardiovascular Genetics, Experimental and Clinical Research Center, Berlin, Germany
- Knappschaftskrankenhaus Recklinghausen, Medizinischen Klinik I Kardiologie, Gastroenterologie und Diabetologie, Recklinghausen, Germany
| | - Philippe Charron
- AP-HP, Département de Génétique et Département de Cardiologie et Inserm UMR 1166, Hopital Pitié-Salpêtrière, Paris, France
- Université de Versailles Saint Quentin en Yvelines, Versailles, France
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54
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The role of genetic testing in unexplained sudden death. Transl Res 2016; 168:59-73. [PMID: 26143861 DOI: 10.1016/j.trsl.2015.06.007] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/01/2015] [Revised: 06/08/2015] [Accepted: 06/11/2015] [Indexed: 12/19/2022]
Abstract
Most sudden deaths are because of a cardiac etiology and are termed sudden cardiac death (SCD). In younger individuals coronary artery disease is less prevalent and cardiac genetic disorders are more common. If sudden death is unexplained despite an appropriate autopsy and toxicologic assessment the term sudden arrhythmic death syndrome (SADS) may be used. This is an umbrella term and common underlying etiologies are primary arrhythmia syndromes with a familial basis such as Brugada syndrome, long QT syndrome, and subtle forms of cardiomyopathy. The first clinical presentation of these conditions is often SCD, which makes identification, screening, and risk stratification crucial to avert further deaths. This review will focus on genetic testing in the context of family screening. It will address the role of the "molecular autopsy" alongside current postmortem practices in the evaluation of SADS deaths. We describe the current data underlying genetic testing in these conditions, explore the potential for next-generation sequencing, and discuss the inherent diagnostic problems in determination of pathogenicity.
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55
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Marian AJ. Clinical applications of molecular genetic discoveries. Transl Res 2016; 168:6-14. [PMID: 26548329 PMCID: PMC4718781 DOI: 10.1016/j.trsl.2015.10.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/05/2015] [Revised: 10/13/2015] [Accepted: 10/17/2015] [Indexed: 01/08/2023]
Abstract
Genome-wide association studies of complex traits have mapped >15,000 common single nucleotide variants (SNVs). Likewise, applications of massively parallel nucleic acid sequencing technologies often referred to as next-generation sequencing to molecular genetic studies of complex traits have catalogued a large number of rare variants (population frequency of <0.01) in cases with complex traits. Moreover, high-throughput nucleic acid sequencing, variant burden analysis, and linkage studies are illuminating the presence of large number of SNVs in cases and families with single-gene disorders. The plethora of the genetic variants has exposed the formidable challenge of identifying the causal and pathogenic variants from the enormous number of innocuous common and rare variants that exist in the population and in an individual genome. The arduous task of identifying the causal and pathogenic variants is further compounded by the pleiotropic effects of the variants, complexity of cis and trans interactions in the genome, variability in phenotypic expression of the disease, as well as phenotypic plasticity, and the multifarious determinants of the phenotype. Population genetic studies offer the initial roadmaps and have the potential to elucidate novel pathways involved in the pathogenesis of the disease. However, the genome of an individual is unique, rendering unambiguous identification of the causal or pathogenic variant in a single individual exceedingly challenging. Yet, the focus of the practice of medicine is on the individual, as Sir William Osler elegantly expressed in his insightful quotation: "The good physician treats the disease; the great physician treats the patient who has the disease." The daunting task facing physicians, patients, and researchers alike is to apply the modern genetic discoveries to care of the individual with or at risk of the disease.
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Affiliation(s)
- Ali J Marian
- Center for Cardiovascular Genetics, The Brown Foundation Institute of Molecular Medicine, The University of Texas Health Science Center, Houston, Tex; Center for Cardiovascular Genetics, Texas Heart Institute, Houston, Tex.
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56
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Karbassi I, Maston GA, Love A, DiVincenzo C, Braastad CD, Elzinga CD, Bright AR, Previte D, Zhang K, Rowland CM, McCarthy M, Lapierre JL, Dubois F, Medeiros KA, Batish SD, Jones J, Liaquat K, Hoffman CA, Jaremko M, Wang Z, Sun W, Buller-Burckle A, Strom CM, Keiles SB, Higgins JJ. A Standardized DNA Variant Scoring System for Pathogenicity Assessments in Mendelian Disorders. Hum Mutat 2015; 37:127-34. [PMID: 26467025 PMCID: PMC4737317 DOI: 10.1002/humu.22918] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2015] [Accepted: 10/07/2015] [Indexed: 11/08/2022]
Abstract
We developed a rules‐based scoring system to classify DNA variants into five categories including pathogenic, likely pathogenic, variant of uncertain significance (VUS), likely benign, and benign. Over 16,500 pathogenicity assessments on 11,894 variants from 338 genes were analyzed for pathogenicity based on prediction tools, population frequency, co‐occurrence, segregation, and functional studies collected from internal and external sources. Scores were calculated by trained scientists using a quantitative framework that assigned differential weighting to these five types of data. We performed descriptive and comparative statistics on the dataset and tested interobserver concordance among the trained scientists. Private variants defined as variants found within single families (n = 5,182), were either VUS (80.5%; n = 4,169) or likely pathogenic (19.5%; n = 1,013). The remaining variants (n = 6,712) were VUS (38.4%; n = 2,577) or likely benign/benign (34.7%; n = 2,327) or likely pathogenic/pathogenic (26.9%, n = 1,808). Exact agreement between the trained scientists on the final variant score was 98.5% [95% confidence interval (CI) (98.0, 98.9)] with an interobserver consistency of 97% [95% CI (91.5, 99.4)]. Variant scores were stable and showed increasing odds of being in agreement with new data when re‐evaluated periodically. This carefully curated, standardized variant pathogenicity scoring system provides reliable pathogenicity scores for DNA variants encountered in a clinical laboratory setting.
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Affiliation(s)
- Izabela Karbassi
- Quest Diagnostics, Athena Diagnostics, Marlborough, Massachusetts
| | - Glenn A Maston
- Quest Diagnostics, Athena Diagnostics, Marlborough, Massachusetts
| | - Angela Love
- Quest Diagnostics, Athena Diagnostics, Marlborough, Massachusetts
| | | | - Corey D Braastad
- Quest Diagnostics, Athena Diagnostics, Marlborough, Massachusetts
| | | | - Alison R Bright
- Quest Diagnostics, Athena Diagnostics, Marlborough, Massachusetts
| | - Domenic Previte
- Quest Diagnostics, Athena Diagnostics, Marlborough, Massachusetts
| | - Ke Zhang
- Quest Diagnostics, Nichols Institute, San Juan Capistrano, California
| | | | - Michele McCarthy
- Quest Diagnostics, Athena Diagnostics, Marlborough, Massachusetts
| | | | - Felicita Dubois
- Quest Diagnostics, Athena Diagnostics, Marlborough, Massachusetts
| | | | - Sat Dev Batish
- Quest Diagnostics, Athena Diagnostics, Marlborough, Massachusetts
| | - Jeffrey Jones
- Quest Diagnostics, Athena Diagnostics, Marlborough, Massachusetts
| | - Khalida Liaquat
- Quest Diagnostics, Athena Diagnostics, Marlborough, Massachusetts
| | - Carol A Hoffman
- Quest Diagnostics, Athena Diagnostics, Marlborough, Massachusetts
| | | | - Zhenyuan Wang
- Quest Diagnostics, Athena Diagnostics, Marlborough, Massachusetts
| | - Weimin Sun
- Quest Diagnostics, Nichols Institute, San Juan Capistrano, California
| | | | - Charles M Strom
- Quest Diagnostics, Nichols Institute, San Juan Capistrano, California
| | - Steven B Keiles
- Quest Diagnostics, Nichols Institute, San Juan Capistrano, California
| | - Joseph J Higgins
- Quest Diagnostics, Athena Diagnostics, Marlborough, Massachusetts
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Pan S, Sommese RF, Sallam KI, Nag S, Sutton S, Miller SM, Spudich JA, Ruppel KM, Ashley EA. Establishing disease causality for a novel gene variant in familial dilated cardiomyopathy using a functional in-vitro assay of regulated thin filaments and human cardiac myosin. BMC MEDICAL GENETICS 2015; 16:97. [PMID: 26498512 PMCID: PMC4620603 DOI: 10.1186/s12881-015-0243-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/28/2014] [Accepted: 10/16/2015] [Indexed: 11/10/2022]
Abstract
Background As next generation sequencing for the genetic diagnosis of cardiovascular disorders becomes more widely used, establishing causality for putative disease causing variants becomes increasingly relevant. Diseases of the cardiac sarcomere provide a particular challenge in this regard because of the complexity of assaying the effect of genetic variants in human cardiac contractile proteins. Results In this study we identified a novel variant R205Q in the cardiac troponin T gene (TNNT2). Carriers of the variant allele exhibited increased chamber volumes associated with decreased left ventricular ejection fraction. To clarify the causal role of this variant, we generated recombinant variant human protein and examined its calcium kinetics as well as the maximally activated ADP release of human β-cardiac myosin with regulated thin filaments containing the mutant troponin T. We found that the R205Q mutation significantly decreased the calcium sensitivity of the thin filament by altering the effective calcium dissociation kinetics. Conclusions The development of moderate throughput post-genomic assays is an essential step in the realization of the potential of next generation sequencing. Although technically challenging, biochemical and functional assays of human cardiac contractile proteins of the thin filament can be achieved and provide an orthogonal source of information to inform the question of causality for individual variants.
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Affiliation(s)
- Stephen Pan
- Leon H. Charney Division of Cardiology, NYU Langone Medical Center, New York, NY, USA.
| | - Ruth F Sommese
- Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, MN, USA.
| | - Karim I Sallam
- Departments of Medicine (Cardiovascular Medicine), Stanford University School of Medicine, Stanford, CA, USA.
| | - Suman Nag
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA, USA.
| | - Shirley Sutton
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA, USA.
| | - Susan M Miller
- Department of Pharmaceutical Chemistry, University of California San Francisco, San Francisco, CA, USA.
| | - James A Spudich
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA, USA.
| | - Kathleen M Ruppel
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA, USA. .,Department of Pediatrics (Cardiology), Stanford University School of Medicine, Stanford, CA, USA.
| | - Euan A Ashley
- Departments of Medicine (Cardiovascular Medicine), Stanford University School of Medicine, Stanford, CA, USA.
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58
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Waldmüller S, Schroeder C, Sturm M, Scheffold T, Imbrich K, Junker S, Frische C, Hofbeck M, Bauer P, Bonin M, Gawaz M, Gramlich M. Targeted 46-gene and clinical exome sequencing for mutations causing cardiomyopathies. Mol Cell Probes 2015; 29:308-14. [DOI: 10.1016/j.mcp.2015.05.004] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2015] [Revised: 05/05/2015] [Accepted: 05/05/2015] [Indexed: 12/18/2022]
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59
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Theis JL, Zimmermann MT, Evans JM, Eckloff BW, Wieben ED, Qureshi MY, O’Leary PW, Olson TM. Recessive
MYH6
Mutations in Hypoplastic Left Heart With Reduced Ejection Fraction. ACTA ACUST UNITED AC 2015; 8:564-71. [DOI: 10.1161/circgenetics.115.001070] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2015] [Accepted: 06/09/2015] [Indexed: 12/28/2022]
Abstract
Background—
The molecular underpinnings of hypoplastic left heart are poorly understood. Staged surgical palliation has dramatically improved survival, yet eventual failure of the systemic right ventricle necessitates cardiac transplantation in a subset of patients. We sought to identify genetic determinants of hypoplastic left heart with latent right ventricular dysfunction in individuals with a Fontan circulation.
Methods and Results—
Evaluation of cardiac structure and function by echocardiography in patients with hypoplastic left heart and their first-degree relatives identified 5 individuals with right ventricular ejection fraction ≤40% after Fontan operation. Whole genome sequencing was performed on DNA from 21 family members, filtering for genetic variants with allele frequency <1% predicted to alter protein structure or expression. Secondary family-based filtering for de novo and recessive variants revealed rare inherited missense mutations on both paternal and maternal alleles of
MYH6
, encoding myosin heavy chain 6, in 2 patients who developed right ventricular dysfunction 3 to 11 years postoperatively. Parents and siblings who were heterozygous carriers had normal echocardiograms. Protein modeling of the 4 highly conserved amino acid substitutions, residing in both head and tail domains, predicted perturbation of protein structure and function.
Conclusions—
In contrast to dominant
MYH6
mutations with variable penetrance identified in other congenital heart defects and dilated cardiomyopathy, this study reveals compound heterozygosity for recessive
MYH6
mutations in patients with hypoplastic left heart and reduced systemic right ventricular ejection fraction. These findings implicate a shared molecular basis for the developmental arrest and latent myopathy of left and right ventricles, respectively.
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Affiliation(s)
- Jeanne L. Theis
- From the Cardiovascular Genetics Research Laboratory (J.L.T., T.M.O.), Division of Pediatric Cardiology, Department of Pediatric and Adolescent Medicine (M.Y.Q., P.W.O’L., T.M.O.), Division of Cardiovascular Diseases, Department of Internal Medicine (T.M.O.), Departments of Health Sciences Research and Biomedical Statistics and Informatics (M.T.Z., J.M.E.), Medical Genome Facility (B.W.E., E.D.W.), and Department of Biochemistry and Molecular Biology (E.D.W.), Mayo Clinic, Rochester, MN
| | - Michael T. Zimmermann
- From the Cardiovascular Genetics Research Laboratory (J.L.T., T.M.O.), Division of Pediatric Cardiology, Department of Pediatric and Adolescent Medicine (M.Y.Q., P.W.O’L., T.M.O.), Division of Cardiovascular Diseases, Department of Internal Medicine (T.M.O.), Departments of Health Sciences Research and Biomedical Statistics and Informatics (M.T.Z., J.M.E.), Medical Genome Facility (B.W.E., E.D.W.), and Department of Biochemistry and Molecular Biology (E.D.W.), Mayo Clinic, Rochester, MN
| | - Jared M. Evans
- From the Cardiovascular Genetics Research Laboratory (J.L.T., T.M.O.), Division of Pediatric Cardiology, Department of Pediatric and Adolescent Medicine (M.Y.Q., P.W.O’L., T.M.O.), Division of Cardiovascular Diseases, Department of Internal Medicine (T.M.O.), Departments of Health Sciences Research and Biomedical Statistics and Informatics (M.T.Z., J.M.E.), Medical Genome Facility (B.W.E., E.D.W.), and Department of Biochemistry and Molecular Biology (E.D.W.), Mayo Clinic, Rochester, MN
| | - Bruce W. Eckloff
- From the Cardiovascular Genetics Research Laboratory (J.L.T., T.M.O.), Division of Pediatric Cardiology, Department of Pediatric and Adolescent Medicine (M.Y.Q., P.W.O’L., T.M.O.), Division of Cardiovascular Diseases, Department of Internal Medicine (T.M.O.), Departments of Health Sciences Research and Biomedical Statistics and Informatics (M.T.Z., J.M.E.), Medical Genome Facility (B.W.E., E.D.W.), and Department of Biochemistry and Molecular Biology (E.D.W.), Mayo Clinic, Rochester, MN
| | - Eric D. Wieben
- From the Cardiovascular Genetics Research Laboratory (J.L.T., T.M.O.), Division of Pediatric Cardiology, Department of Pediatric and Adolescent Medicine (M.Y.Q., P.W.O’L., T.M.O.), Division of Cardiovascular Diseases, Department of Internal Medicine (T.M.O.), Departments of Health Sciences Research and Biomedical Statistics and Informatics (M.T.Z., J.M.E.), Medical Genome Facility (B.W.E., E.D.W.), and Department of Biochemistry and Molecular Biology (E.D.W.), Mayo Clinic, Rochester, MN
| | - Muhammad Y. Qureshi
- From the Cardiovascular Genetics Research Laboratory (J.L.T., T.M.O.), Division of Pediatric Cardiology, Department of Pediatric and Adolescent Medicine (M.Y.Q., P.W.O’L., T.M.O.), Division of Cardiovascular Diseases, Department of Internal Medicine (T.M.O.), Departments of Health Sciences Research and Biomedical Statistics and Informatics (M.T.Z., J.M.E.), Medical Genome Facility (B.W.E., E.D.W.), and Department of Biochemistry and Molecular Biology (E.D.W.), Mayo Clinic, Rochester, MN
| | - Patrick W. O’Leary
- From the Cardiovascular Genetics Research Laboratory (J.L.T., T.M.O.), Division of Pediatric Cardiology, Department of Pediatric and Adolescent Medicine (M.Y.Q., P.W.O’L., T.M.O.), Division of Cardiovascular Diseases, Department of Internal Medicine (T.M.O.), Departments of Health Sciences Research and Biomedical Statistics and Informatics (M.T.Z., J.M.E.), Medical Genome Facility (B.W.E., E.D.W.), and Department of Biochemistry and Molecular Biology (E.D.W.), Mayo Clinic, Rochester, MN
| | - Timothy M. Olson
- From the Cardiovascular Genetics Research Laboratory (J.L.T., T.M.O.), Division of Pediatric Cardiology, Department of Pediatric and Adolescent Medicine (M.Y.Q., P.W.O’L., T.M.O.), Division of Cardiovascular Diseases, Department of Internal Medicine (T.M.O.), Departments of Health Sciences Research and Biomedical Statistics and Informatics (M.T.Z., J.M.E.), Medical Genome Facility (B.W.E., E.D.W.), and Department of Biochemistry and Molecular Biology (E.D.W.), Mayo Clinic, Rochester, MN
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Skrzynia C, Berg JS, Willis MS, Jensen BC. Genetics and heart failure: a concise guide for the clinician. Curr Cardiol Rev 2015; 11:10-7. [PMID: 24251456 PMCID: PMC4347203 DOI: 10.2174/1573403x09666131117170446] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/09/2013] [Revised: 07/09/2013] [Accepted: 09/25/2013] [Indexed: 12/11/2022] Open
Abstract
The pathogenesis of heart failure involves a complex interaction between genetic and environmental factors. Genetic factors may influence the susceptibility to the underlying etiology of heart failure, the rapidity of disease progression, or the response to pharmacologic therapy. The genetic contribution to heart failure is relatively minor in most multifactorial cases, but more direct and profound in the case of familial dilated cardiomyopathy. Early studies of genetic risk for heart failure focused on polymorphisms in genes integral to the adrenergic and renin-angiotensin-aldosterone system. Some of these variants were found to increase the risk of developing heart failure, and others appeared to affect the therapeutic response to neurohormonal antagonists. Regardless, each variant individually confers a relatively modest increase in risk and likely requires complex interaction with other variants and the environment for heart failure to develop. Dilated cardiomyopathy frequently leads to heart failure, and a genetic etiology increasingly has been recognized in cases previously considered to be "idiopathic". Up to 50% of dilated cardiomyopathy cases without other cause likely are due to a heritable genetic mutation. Such mutations typically are found in genes encoding sarcomeric proteins and are inherited in an autosomal dominant fashion. In recent years, rapid advances in sequencing technology have improved our ability to diagnose familial dilated cardiomyopathy and those diagnostic tests are available widely. Optimal care for the expanding population of patients with heritable heart failure involves counselors and physicians with specialized training in genetics, but numerous online genetics resources are available to practicing clinicians.
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Affiliation(s)
| | | | | | - Brian C Jensen
- UNC Division of Cardiology, 160 Dental Circle, CB 7075, Chapel Hill, NC 27599-7075, USA.
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61
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Huang W, Liang J, Yuan CC, Kazmierczak K, Zhou Z, Morales A, McBride KL, Fitzgerald-Butt SM, Hershberger RE, Szczesna-Cordary D. Novel familial dilated cardiomyopathy mutation in MYL2 affects the structure and function of myosin regulatory light chain. FEBS J 2015; 282:2379-93. [PMID: 25825243 DOI: 10.1111/febs.13286] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2014] [Revised: 02/27/2015] [Accepted: 03/26/2015] [Indexed: 01/16/2023]
Abstract
Dilated cardiomyopathy (DCM) is a disease of the myocardium characterized by left ventricular dilatation and diminished contractile function. Here we describe a novel DCM mutation in the myosin regulatory light chain (RLC), in which aspartic acid at position 94 is replaced by alanine (D94A). The mutation was identified by exome sequencing of three adult first-degree relatives who met formal criteria for idiopathic DCM. To obtain insight into the functional significance of this pathogenic MYL2 variant, we cloned and purified the human ventricular RLC wild-type (WT) and D94A mutant proteins, and performed in vitro experiments using RLC-mutant or WT-reconstituted porcine cardiac preparations. The mutation induced a reduction in the α-helical content of the RLC, and imposed intra-molecular rearrangements. The phosphorylation of RLC by Ca²⁺/calmodulin-activated myosin light chain kinase was not affected by D94A. The mutation was seen to impair binding of RLC to the myosin heavy chain, and its incorporation into RLC-depleted porcine myosin. The actin-activated ATPase activity of mutant-reconstituted porcine cardiac myosin was significantly higher compared with ATPase of wild-type. No changes in the myofibrillar ATPase-pCa relationship were observed in wild-type- or D94A-reconstituted preparations. Measurements of contractile force showed a slightly reduced maximal tension per cross-section of muscle, with no change in the calcium sensitivity of force in D94A-reconstituted skinned porcine papillary muscle strips compared with wild-type. Our data indicate that subtle structural rearrangements in the RLC molecule, followed by its impaired interaction with the myosin heavy chain, may trigger functional abnormalities contributing to the DCM phenotype.
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Affiliation(s)
- Wenrui Huang
- Department of Molecular and Cellular Pharmacology, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Jingsheng Liang
- Department of Molecular and Cellular Pharmacology, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Chen-Ching Yuan
- Department of Molecular and Cellular Pharmacology, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Katarzyna Kazmierczak
- Department of Molecular and Cellular Pharmacology, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Zhiqun Zhou
- Department of Molecular and Cellular Pharmacology, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Ana Morales
- Division of Human Genetics, Department of Internal Medicine, Wexner Medical Center, Ohio State University, Columbus, OH, USA
| | - Kim L McBride
- Department of Pediatrics Ohio State University, Center for Cardiovascular and Pulmonary Research, Nationwide Children's Hospital, Columbus, OH, USA
| | - Sara M Fitzgerald-Butt
- Department of Pediatrics Ohio State University, Center for Cardiovascular and Pulmonary Research, Nationwide Children's Hospital, Columbus, OH, USA
| | - Ray E Hershberger
- Division of Human Genetics, Department of Internal Medicine, Wexner Medical Center, Ohio State University, Columbus, OH, USA
| | - Danuta Szczesna-Cordary
- Department of Molecular and Cellular Pharmacology, University of Miami Miller School of Medicine, Miami, FL, USA
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Pérez-Serra A, Toro R, Campuzano O, Sarquella-Brugada G, Berne P, Iglesias A, Mangas A, Brugada J, Brugada R. A novel mutation in lamin a/c causing familial dilated cardiomyopathy associated with sudden cardiac death. J Card Fail 2015; 21:217-225. [PMID: 25498755 DOI: 10.1016/j.cardfail.2014.12.003] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2014] [Revised: 10/23/2014] [Accepted: 12/03/2014] [Indexed: 12/17/2022]
Abstract
BACKGROUND Dilated cardiomyopathy (DCM), a cardiac heterogeneous pathology characterized by left ventricular or biventricular dilatation, is a leading cause of heart failure and heart transplantation. The genetic origin of DCM remains unknown in most cases, but >50 genes have been associated with DCM. We sought to identify the genetic implication and perform a genetic analysis in a Spanish family affected by DCM and sudden cardiac death. METHODS AND RESULTS Clinical assessment and genetic screening were performed in the index case as well as family members. Of all relatives clinically assessed, nine patients showed clinical symptoms related to the pathology. Genetic screening identified 20 family members who carried a novel mutation in LMNA (c.871 G>A, p.E291K). Family segregation analysis indicated that all clinically affected patients carried this novel mutation. Clinical assessment of genetic carriers showed that electrical dysfunction was present previous to mechanical and structural abnormalities. CONCLUSIONS Our results report a novel pathogenic mutation associated with DCM, supporting the benefits of comprehensive genetic studies of families affected by this pathology.
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Affiliation(s)
| | - Rocío Toro
- School of Medicine, University of Cadiz, Cádiz, Spain
| | - Oscar Campuzano
- Cardiovascular Genetics Center, IDIBGI, University of Girona, Girona, Spain; Department of Medical Science, School of Medicine, University of Girona, Girona, Spain
| | | | - Paola Berne
- Hospital Clínic de Barcelona, University of Barcelona, Barcelona, Spain
| | - Anna Iglesias
- Cardiovascular Genetics Center, IDIBGI, University of Girona, Girona, Spain
| | - Alipio Mangas
- School of Medicine, University of Cadiz, Cádiz, Spain
| | - Josep Brugada
- Hospital Clínic de Barcelona, University of Barcelona, Barcelona, Spain
| | - Ramon Brugada
- Cardiovascular Genetics Center, IDIBGI, University of Girona, Girona, Spain; Department of Medical Science, School of Medicine, University of Girona, Girona, Spain; Cardiomyopathy Unit, Hospital Josep Trueta, University of Girona, Girona, Spain.
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Maciąg A, Villa F, Ferrario A, Spinelli CC, Carrizzo A, Malovini A, Torella A, Montenero C, Parisi A, Condorelli G, Vecchione C, Nigro V, Montenero AS, Puca AA. Exome sequencing of a family with lone, autosomal dominant atrial flutter identifies a rare variation in ABCB4 significantly enriched in cases. BMC Genet 2015; 16:15. [PMID: 25888430 PMCID: PMC4342200 DOI: 10.1186/s12863-015-0177-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2014] [Accepted: 01/30/2015] [Indexed: 12/23/2022] Open
Abstract
Background Lone atrial flutter (AFL) and atrial fibrillation (AF) are common and sometimes consequential cardiac conduction disorders with a strong heritability, as underlined by recent genome-wide association studies that identified genetic modifiers. Follow-up family-based genetic analysis also identified Mendelian transmission of disease alleles. Three affected members were exome-sequenced for the identification of potential causative mutations, which were subsequently validated by direct sequencing in the other 3 affected members. Taqman assay was then used to confirm the role of any mutation in an independent population of sporadic lone AFL/AF cases. Results The family cluster analysis provided evidence of genetic inheritance of AFL in the family via autosomal dominant transmission. The exome-sequencing of 3 family members identified 7 potential mutations: of these, rs58238559, a rare missense genetic variant in the ATP-binding cassette sub-family B, member 4 (ABCB4) gene was carried by all affected members. Further analysis of 82 subjects with sporadic lone AF, 63 subjects with sporadic lone AFL, and 673 controls revealed that the allele frequency for this variation was significantly higher in cases than in the controls (0.05 vs. 0.01; OR = 3.73; 95% CI = 1.16–11.49; P = 0.013). Conclusions rs58238559 in ABCB4 is a rare missense variant with a significant effect on the development of AFL/AF. Electronic supplementary material The online version of this article (doi:10.1186/s12863-015-0177-0) contains supplementary material, which is available to authorized users.
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Affiliation(s)
| | | | | | | | | | | | | | | | - Attilio Parisi
- Università degli Studi di Roma "Foro Italico", Rome, Italy.
| | - Gianluigi Condorelli
- Humanitas Clinical and Research Center, Rozzano, MI, Italy. .,Università degli Studi di Milano, Milan, Italy.
| | - Carmine Vecchione
- IRCCS Neuromed, Parco Tecnologico, Pozzilli, IS, Italy. .,Università degli Studi di Salerno, Salerno, Italy.
| | - Vincenzo Nigro
- Seconda Università degli Studi di Napoli, Napoli, Italy.
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Ho CY, Charron P, Richard P, Girolami F, Van Spaendonck-Zwarts KY, Pinto Y. Genetic advances in sarcomeric cardiomyopathies: state of the art. Cardiovasc Res 2015; 105:397-408. [PMID: 25634555 PMCID: PMC4349164 DOI: 10.1093/cvr/cvv025] [Citation(s) in RCA: 169] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Genetic studies in the 1980s and 1990s led to landmark discoveries that sarcomere mutations cause both hypertrophic and dilated cardiomyopathies. Sarcomere mutations also likely play a role in more complex phenotypes and overlap cardiomyopathies with features of hypertrophy, dilation, diastolic abnormalities, and non-compaction. Identification of the genetic cause of these important conditions provides unique opportunities to interrogate and characterize disease pathogenesis and pathophysiology, starting from the molecular level and expanding from there. With such insights, there is potential for clinical translation that may transform management of patients and families with inherited cardiomyopathies. If key pathways for disease development can be identified, they could potentially serve as targets for novel disease-modifying or disease-preventing therapies. By utilizing gene-based diagnostic testing, we can identify at-risk individuals prior to the onset of clinical disease, allowing for disease-modifying therapy to be initiated early in life, at a time that such treatment may be most successful. In this section, we review the current application of genetics in clinical management, focusing on hypertrophic cardiomyopathy as a paradigm; discuss state-of-the-art genetic testing technology; review emerging knowledge of gene expression in sarcomeric cardiomyopathies; and discuss both the prospects, as well as the challenges, of bringing genetics to medicine.
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Affiliation(s)
- Carolyn Y Ho
- Cardiovascular Division, Brigham and Women's Hospital, Boston, MA, USA
| | - Philippe Charron
- Centre de référence maladies cardiaques héréditaires, ICAN, Inserm UMR_1166, Hôpital Pitié-Salpêtrière, AP-HP, Paris, France Université de Versailles-Saint Quentin, Hôpital Ambroise Paré, AP-HP, Boulogne-Billancourt, France
| | - Pascale Richard
- Centre de référence maladies cardiaques héréditaires, ICAN, Inserm UMR_1166, Hôpital Pitié-Salpêtrière, AP-HP, Paris, France
| | | | - Karin Y Van Spaendonck-Zwarts
- Department of Clinical Genetics, Academic Medical Center Amsterdam, University of Amsterdam, Amsterdam, The Netherlands
| | - Yigal Pinto
- Department of Cardiology, Academic Medical Center Amsterdam, University of Amsterdam, Amsterdam, The Netherlands
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Nonsense Mutations in BAG3 are Associated With Early-Onset Dilated Cardiomyopathy in French Canadians. Can J Cardiol 2014; 30:1655-61. [DOI: 10.1016/j.cjca.2014.09.030] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2014] [Revised: 09/10/2014] [Accepted: 09/25/2014] [Indexed: 01/04/2023] Open
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Shearer A, Eppsteiner R, Booth K, Ephraim S, Gurrola J, Simpson A, Black-Ziegelbein E, Joshi S, Ravi H, Giuffre A, Happe S, Hildebrand M, Azaiez H, Bayazit Y, Erdal M, Lopez-Escamez J, Gazquez I, Tamayo M, Gelvez N, Leal G, Jalas C, Ekstein J, Yang T, Usami SI, Kahrizi K, Bazazzadegan N, Najmabadi H, Scheetz T, Braun T, Casavant T, LeProust E, Smith R. Utilizing ethnic-specific differences in minor allele frequency to recategorize reported pathogenic deafness variants. Am J Hum Genet 2014; 95:445-53. [PMID: 25262649 DOI: 10.1016/j.ajhg.2014.09.001] [Citation(s) in RCA: 120] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2014] [Accepted: 09/08/2014] [Indexed: 10/24/2022] Open
Abstract
Ethnic-specific differences in minor allele frequency impact variant categorization for genetic screening of nonsyndromic hearing loss (NSHL) and other genetic disorders. We sought to evaluate all previously reported pathogenic NSHL variants in the context of a large number of controls from ethnically distinct populations sequenced with orthogonal massively parallel sequencing methods. We used HGMD, ClinVar, and dbSNP to generate a comprehensive list of reported pathogenic NSHL variants and re-evaluated these variants in the context of 8,595 individuals from 12 populations and 6 ethnically distinct major human evolutionary phylogenetic groups from three sources (Exome Variant Server, 1000 Genomes project, and a control set of individuals created for this study, the OtoDB). Of the 2,197 reported pathogenic deafness variants, 325 (14.8%) were present in at least one of the 8,595 controls, indicating a minor allele frequency (MAF) > 0.00006. MAFs ranged as high as 0.72, a level incompatible with pathogenicity for a fully penetrant disease like NSHL. Based on these data, we established MAF thresholds of 0.005 for autosomal-recessive variants (excluding specific variants in GJB2) and 0.0005 for autosomal-dominant variants. Using these thresholds, we recategorized 93 (4.2%) of reported pathogenic variants as benign. Our data show that evaluation of reported pathogenic deafness variants using variant MAFs from multiple distinct ethnicities and sequenced by orthogonal methods provides a powerful filter for determining pathogenicity. The proposed MAF thresholds will facilitate clinical interpretation of variants identified in genetic testing for NSHL. All data are publicly available to facilitate interpretation of genetic variants causing deafness.
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67
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Brun F, Barnes CV, Sinagra G, Slavov D, Barbati G, Zhu X, Graw SL, Spezzacatene A, Pinamonti B, Merlo M, Salcedo EE, Sauer WH, Taylor MR, Mestroni L. Titin and desmosomal genes in the natural history of arrhythmogenic right ventricular cardiomyopathy. J Med Genet 2014; 51:669-76. [PMID: 25157032 PMCID: PMC4465780 DOI: 10.1136/jmedgenet-2014-102591] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
BACKGROUND Genotype-phenotype correlations are poorly characterised in arrhythmogenic right ventricular cardiomyopathy (ARVC). We investigated whether carriers of rare variants in desmosomal genes (DC) and titin gene (TTN) display different phenotypes and clinical outcomes compared with non-carriers (NT-ND). METHODS AND RESULTS Thirty-nine ARVC families (173 subjects, 67 affected) with extensive follow-up (mean 9 years), prospectively enrolled in the International Familial Cardiomyopathy Registry since 1991, were screened for rare variants in TTN and desmosomal genes (DSP, PKP2, DSG2, DSC2). Multiple clinical and outcome variables were compared between three genetic groups (TTN, DC, NT-ND) to define genotype-phenotype associations. Of the 39 ARVC families, 13% (5/39) carried TTN rare variants (11 affected subjects), 13% (5/39) DC (8 affected), while 74% (29/39) were NT-ND (48 affected). When compared with NT-ND, DC had a higher prevalence of inverted T waves in V2-3 (75% vs 31%, p=0.004), while TTN had more supraventricular arrhythmias (46% vs 13%, p=0.013) and conduction disease (64% vs 6% p<0.001). When compared with the NT-ND group, the DC group experienced a worse prognosis (67% vs 11%, p=0.03) and exhibited a lower survival free from death or heart transplant (59% vs 95% at 30 years, and 31% vs 89% at 50 years, HR 9.66, p=0.006), while the TTN group showed an intermediate survival curve (HR 4.26, p=0.037). CONCLUSIONS TTN carriers display distinct phenotypic characteristics including a greater risk for supraventricular arrhythmias and conduction disease. Conversely, DC are characterised by negative T waves in anterior leads, severe prognosis, high mortality and morbidity.
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Affiliation(s)
- Francesca Brun
- Cardiovascular Institute and Adult Medical Genetics Program, University of Colorado Denver AMC, Aurora, Colorado, USA
- Cardiovascular Department, Ospedali Riuniti and University of Trieste, Trieste, Italy
| | - Carl V. Barnes
- Cardiovascular Institute and Adult Medical Genetics Program, University of Colorado Denver AMC, Aurora, Colorado, USA
| | - Gianfranco Sinagra
- Cardiovascular Department, Ospedali Riuniti and University of Trieste, Trieste, Italy
| | - Dobromir Slavov
- Cardiovascular Institute and Adult Medical Genetics Program, University of Colorado Denver AMC, Aurora, Colorado, USA
| | - Giulia Barbati
- Cardiovascular Department, Ospedali Riuniti and University of Trieste, Trieste, Italy
| | - Xiao Zhu
- Cardiovascular Institute and Adult Medical Genetics Program, University of Colorado Denver AMC, Aurora, Colorado, USA
| | - Sharon L. Graw
- Cardiovascular Institute and Adult Medical Genetics Program, University of Colorado Denver AMC, Aurora, Colorado, USA
| | - Anita Spezzacatene
- Cardiovascular Institute and Adult Medical Genetics Program, University of Colorado Denver AMC, Aurora, Colorado, USA
- Cardiovascular Department, Ospedali Riuniti and University of Trieste, Trieste, Italy
| | - Bruno Pinamonti
- Cardiovascular Department, Ospedali Riuniti and University of Trieste, Trieste, Italy
| | - Marco Merlo
- Cardiovascular Institute and Adult Medical Genetics Program, University of Colorado Denver AMC, Aurora, Colorado, USA
- Cardiovascular Department, Ospedali Riuniti and University of Trieste, Trieste, Italy
| | - Ernesto E. Salcedo
- Cardiovascular Institute and Adult Medical Genetics Program, University of Colorado Denver AMC, Aurora, Colorado, USA
| | - William H. Sauer
- Cardiovascular Institute and Adult Medical Genetics Program, University of Colorado Denver AMC, Aurora, Colorado, USA
| | - Matthew R.G. Taylor
- Cardiovascular Institute and Adult Medical Genetics Program, University of Colorado Denver AMC, Aurora, Colorado, USA
| | - Luisa Mestroni
- Cardiovascular Institute and Adult Medical Genetics Program, University of Colorado Denver AMC, Aurora, Colorado, USA
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Applications of human-induced pluripotent stem cells in the investigation of inherited cardiomyopathy. Int J Cardiol 2014; 177:604-6. [PMID: 25286769 DOI: 10.1016/j.ijcard.2014.08.135] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/21/2014] [Accepted: 08/26/2014] [Indexed: 11/22/2022]
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69
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MacArthur DG, Manolio TA, Dimmock DP, Rehm HL, Shendure J, Abecasis GR, Adams DR, Altman RB, Antonarakis SE, Ashley EA, Barrett JC, Biesecker LG, Conrad DF, Cooper GM, Cox NJ, Daly MJ, Gerstein MB, Goldstein DB, Hirschhorn JN, Leal SM, Pennacchio LA, Stamatoyannopoulos JA, Sunyaev SR, Valle D, Voight BF, Winckler W, Gunter C. Guidelines for investigating causality of sequence variants in human disease. Nature 2014; 508:469-76. [PMID: 24759409 PMCID: PMC4180223 DOI: 10.1038/nature13127] [Citation(s) in RCA: 967] [Impact Index Per Article: 87.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2013] [Accepted: 02/05/2014] [Indexed: 11/26/2022]
Abstract
The discovery of rare genetic variants is accelerating, and clear guidelines for distinguishing disease-causing sequence variants from the many potentially functional variants present in any human genome are urgently needed. Without rigorous standards we risk an acceleration of false-positive reports of causality, which would impede the translation of genomic research findings into the clinical diagnostic setting and hinder biological understanding of disease. Here we discuss the key challenges of assessing sequence variants in human disease, integrating both gene-level and variant-level support for causality. We propose guidelines for summarizing confidence in variant pathogenicity and highlight several areas that require further resource development.
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Affiliation(s)
- D G MacArthur
- 1] Analytic and Translational Genetics Unit, Massachusetts General Hospital, Boston, Massachusetts 02114, USA [2] Program in Medical and Population Genetics, Broad Institute of Harvard and MIT, Cambridge, Massachusetts 02142, USA
| | - T A Manolio
- Division of Genomic Medicine, National Human Genome Research Institute, Bethesda, Maryland 20892, USA
| | - D P Dimmock
- Division of Genetics, Department of Pediatrics, Medical College of Wisconsin, Milwaukee, Wisconsin 53226, USA
| | - H L Rehm
- 1] Laboratory for Molecular Medicine, Partners Healthcare Center for Personalized Genetic Medicine, Cambridge, Massachusetts 02139, USA [2] Department of Pathology, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - J Shendure
- Department of Genome Sciences, University of Washington, Seattle, Washington 98115, USA
| | - G R Abecasis
- Department of Biostatistics, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - D R Adams
- 1] NIH Undiagnosed Diseases Program, National Institutes of Health Office of Rare Diseases Research and National Human Genome Research Institute, Bethesda, Maryland 20892, USA [2] Office of the Clinical Director, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - R B Altman
- Departments of Bioengineering & Genetics, Stanford University, Stanford, California 94305, USA
| | - S E Antonarakis
- 1] Department of Genetic Medicine, University of Geneva Medical School, 1211 Geneva, Switzerland [2] iGE3 Institute of Genetics and Genomics of Geneva, 1211 Geneva, Switzerland
| | - E A Ashley
- Center for Inherited Cardiovascular Disease, Stanford University School of Medicine, Stanford, California 94305, USA
| | - J C Barrett
- Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge CB10 1HH, UK
| | - L G Biesecker
- Genetic Disease Research Branch, National Human Genome Research Institute, NIH, Bethesda, Maryland 20892, USA
| | - D F Conrad
- Departments of Genetics, Pathology and Immunology, Washington University School of Medicine, St Louis, Missouri 63110, USA
| | - G M Cooper
- HudsonAlpha Institute for Biotechnology, 601 Genome Way, Huntsville, Alabama 35806, USA
| | - N J Cox
- Section of Genetic Medicine, Department of Medicine, University of Chicago, Chicago, Illinois 60637, USA
| | - M J Daly
- 1] Analytic and Translational Genetics Unit, Massachusetts General Hospital, Boston, Massachusetts 02114, USA [2] Program in Medical and Population Genetics, Broad Institute of Harvard and MIT, Cambridge, Massachusetts 02142, USA
| | - M B Gerstein
- 1] Program in Computational Biology and Bioinformatics, Yale University, New Haven, Connecticut 06520, USA [2] Departments of Computer Science, Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06520, USA
| | - D B Goldstein
- Center for Human Genome Variation, Duke University School of Medicine, Durham, North Carolina 27708, USA
| | - J N Hirschhorn
- 1] Program in Medical and Population Genetics, Broad Institute of Harvard and MIT, Cambridge, Massachusetts 02142, USA [2] Divisions of Genetics and Endocrinology, Children's Hospital, Boston, Massachusetts 02115, USA
| | - S M Leal
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas 77030, USA
| | - L A Pennacchio
- 1] Genomics Division, MS 84-171, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA [2] US Department of Energy Joint Genome Institute, Walnut Creek, California 94598, USA
| | - J A Stamatoyannopoulos
- Department of Genome Sciences, University of Washington, 1705 Northeast Pacific Street, Seattle, Washington 98195, USA
| | - S R Sunyaev
- 1] Division of Genetics, Department of Medicine, Brigham and Women's Hospital, Boston, Massachusetts 02115, USA [2] Harvard Medical School, Boston, Massachusetts 02115, USA
| | - D Valle
- McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland 21287, USA
| | - B F Voight
- Department of Pharmacology and Department of Genetics, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania 19104, USA
| | - W Winckler
- 1] Program in Medical and Population Genetics, Broad Institute of Harvard and MIT, Cambridge, Massachusetts 02142, USA [2] Next Generation Diagnostics, Novartis Institutes for BioMedical Research, Cambridge, Massachusetts, USA (W.W.); Marcus Autism Center, Children's Healthcare of Atlanta, Atlanta, Georgia 30329, USA (C.G.)
| | - C Gunter
- 1] HudsonAlpha Institute for Biotechnology, 601 Genome Way, Huntsville, Alabama 35806, USA [2] Next Generation Diagnostics, Novartis Institutes for BioMedical Research, Cambridge, Massachusetts, USA (W.W.); Marcus Autism Center, Children's Healthcare of Atlanta, Atlanta, Georgia 30329, USA (C.G.)
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Semsarian C, Ingles J. Expanding the genetic spectrum of hypertrophic cardiomyopathy: X marks the spot. ACTA ACUST UNITED AC 2014; 6:528-30. [PMID: 24347617 DOI: 10.1161/circgenetics.113.000377] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Christopher Semsarian
- Agnes Ginges Centre for Molecular Cardiology, Centenary Institute, Newtown, Australia
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Savio-Galimberti E, Weeke P, Muhammad R, Blair M, Ansari S, Short L, Atack TC, Kor K, Vanoye CG, Olesen MS, LuCamp, Yang T, George AL, Roden DM, Darbar D. SCN10A/Nav1.8 modulation of peak and late sodium currents in patients with early onset atrial fibrillation. Cardiovasc Res 2014; 104:355-63. [PMID: 25053638 DOI: 10.1093/cvr/cvu170] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
AIMS To test the hypothesis that vulnerability to atrial fibrillation (AF) is associated with rare coding sequence variation in the SCN10A gene, which encodes the voltage-gated sodium channel isoform NaV1.8 found primarily in peripheral nerves and to identify potentially disease-related mechanisms in high-priority rare variants using in-vitro electrophysiology. METHODS AND RESULTS We re-sequenced SCN10A in 274 patients with early onset AF from the Vanderbilt AF Registry to identify rare coding variants. Engineered variants were transiently expressed in ND7/23 cells and whole-cell voltage clamp experiments were conducted to elucidate their functional properties. Resequencing SCN10A identified 18 heterozygous rare coding variants (minor allele frequency ≤1%) in 18 (6.6%) AF probands. Four probands were carriers of two rare variants each and 14 were carriers of one coding variant. Based on evidence of co-segregation, initial assessment of functional importance, and presence in ≥1 AF proband, three variants (417delK, A1886V, and the compound variant Y158D-R814H) were selected for functional studies. The 417delK variant displayed near absent current while A1886V and Y158D-R814H exhibited enhanced peak and late (INa-L) sodium currents; both Y158D and R818H individually contributed to this phenotype. CONCLUSION Rare SCN10A variants encoding Nav1.8 were identified in 6.6% of patients with early onset AF. In-vitro electrophysiological studies demonstrated profoundly altered function in 3/3 high-priority variants. Collectively, these data strongly support the hypothesis that rare SCN10A variants may contribute to AF susceptibility.
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Affiliation(s)
- Eleonora Savio-Galimberti
- Division of Cardiovascular Medicine, Vanderbilt University School of Medicine, 2215B Garland Avenue, Room 1285A MRB IV, Nashville, TN 37323-6602, USA
| | - Peter Weeke
- Division of Clinical Pharmacology, Vanderbilt University School of Medicine, 2215B Garland Avenue, Room 1285A MRB IV, Nashville, TN 37323-6602, USA
| | - Raafia Muhammad
- Division of Cardiovascular Medicine, Vanderbilt University School of Medicine, 2215B Garland Avenue, Room 1285A MRB IV, Nashville, TN 37323-6602, USA
| | - Marcia Blair
- Division of Cardiovascular Medicine, Vanderbilt University School of Medicine, 2215B Garland Avenue, Room 1285A MRB IV, Nashville, TN 37323-6602, USA
| | - Sami Ansari
- Division of Cardiovascular Medicine, Vanderbilt University School of Medicine, 2215B Garland Avenue, Room 1285A MRB IV, Nashville, TN 37323-6602, USA
| | - Laura Short
- Division of Clinical Pharmacology, Vanderbilt University School of Medicine, 2215B Garland Avenue, Room 1285A MRB IV, Nashville, TN 37323-6602, USA
| | - Thomas C Atack
- Division of Clinical Pharmacology, Vanderbilt University School of Medicine, 2215B Garland Avenue, Room 1285A MRB IV, Nashville, TN 37323-6602, USA
| | - Kaylen Kor
- Division of Cardiovascular Medicine, Vanderbilt University School of Medicine, 2215B Garland Avenue, Room 1285A MRB IV, Nashville, TN 37323-6602, USA
| | - Carlos G Vanoye
- Division of Genetic Medicine, Vanderbilt University School of Medicine, Nashville, TN 37323-6602, USA
| | - Morten Salling Olesen
- Danish National Research Centre for Cardiac Arrhythmia, Rigshospitalet, University of Copenhagen, Denmark
| | - LuCamp
- LuCamp, The Lundbeck Foundation Centre for Applied Medical Genomics in Personalized Disease Prediction, Copenhagen, Denmark
| | - Tao Yang
- Division of Clinical Pharmacology, Vanderbilt University School of Medicine, 2215B Garland Avenue, Room 1285A MRB IV, Nashville, TN 37323-6602, USA
| | - Alfred L George
- Division of Genetic Medicine, Vanderbilt University School of Medicine, Nashville, TN 37323-6602, USA
| | - Dan M Roden
- Division of Cardiovascular Medicine, Vanderbilt University School of Medicine, 2215B Garland Avenue, Room 1285A MRB IV, Nashville, TN 37323-6602, USA Division of Clinical Pharmacology, Vanderbilt University School of Medicine, 2215B Garland Avenue, Room 1285A MRB IV, Nashville, TN 37323-6602, USA
| | - Dawood Darbar
- Division of Cardiovascular Medicine, Vanderbilt University School of Medicine, 2215B Garland Avenue, Room 1285A MRB IV, Nashville, TN 37323-6602, USA Division of Clinical Pharmacology, Vanderbilt University School of Medicine, 2215B Garland Avenue, Room 1285A MRB IV, Nashville, TN 37323-6602, USA
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Lawrence L, Sincan M, Markello T, Adams DR, Gill F, Godfrey R, Golas G, Groden C, Landis D, Nehrebecky M, Park G, Soldatos A, Tifft C, Toro C, Wahl C, Wolfe L, Gahl WA, Boerkoel CF. The implications of familial incidental findings from exome sequencing: the NIH Undiagnosed Diseases Program experience. Genet Med 2014; 16:741-50. [PMID: 24784157 PMCID: PMC4190001 DOI: 10.1038/gim.2014.29] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2013] [Accepted: 02/18/2014] [Indexed: 02/08/2023] Open
Abstract
PURPOSE Using exome sequence data from 159 families participating in the National Institutes of Health Undiagnosed Diseases Program, we evaluated the number and inheritance mode of reportable incidental sequence variants. METHODS Following the American College of Medical Genetics and Genomics recommendations for reporting of incidental findings from next-generation sequencing, we extracted variants in 56 genes from the exome sequence data of 543 subjects and determined the reportable incidental findings for each participant. We also defined variant status as inherited or de novo for those with available parental sequence data. RESULTS We identified 14 independent reportable variants in 159 (8.8%) families. For nine families with parental sequence data in our cohort, a parent transmitted the variant to one or more children (nine minor children and four adult children). The remaining five variants occurred in adults for whom parental sequences were unavailable. CONCLUSION Our results are consistent with the expectation that a small percentage of exomes will result in identification of an incidental finding under the American College of Medical Genetics and Genomics recommendations. Additionally, our analysis of family sequence data highlights that genome and exome sequencing of families has unavoidable implications for immediate family members and therefore requires appropriate counseling for the family.
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Affiliation(s)
- Lauren Lawrence
- 1] National Institutes of Health (NIH) Undiagnosed Diseases Program, Common Fund, NIH Office of the Director and National Human Genome Research Institute, Bethesda, Maryland, USA [2] Keck School of Medicine, University of Southern California, Los Angeles, California, USA
| | - Murat Sincan
- National Institutes of Health (NIH) Undiagnosed Diseases Program, Common Fund, NIH Office of the Director and National Human Genome Research Institute, Bethesda, Maryland, USA
| | - Thomas Markello
- National Institutes of Health (NIH) Undiagnosed Diseases Program, Common Fund, NIH Office of the Director and National Human Genome Research Institute, Bethesda, Maryland, USA
| | - David R Adams
- National Institutes of Health (NIH) Undiagnosed Diseases Program, Common Fund, NIH Office of the Director and National Human Genome Research Institute, Bethesda, Maryland, USA
| | - Fred Gill
- Internal Medicine Consult Service, NIH Clinical Center, Bethesda, Maryland, USA
| | - Rena Godfrey
- National Institutes of Health (NIH) Undiagnosed Diseases Program, Common Fund, NIH Office of the Director and National Human Genome Research Institute, Bethesda, Maryland, USA
| | - Gretchen Golas
- National Institutes of Health (NIH) Undiagnosed Diseases Program, Common Fund, NIH Office of the Director and National Human Genome Research Institute, Bethesda, Maryland, USA
| | - Catherine Groden
- National Institutes of Health (NIH) Undiagnosed Diseases Program, Common Fund, NIH Office of the Director and National Human Genome Research Institute, Bethesda, Maryland, USA
| | - Dennis Landis
- National Institutes of Health (NIH) Undiagnosed Diseases Program, Common Fund, NIH Office of the Director and National Human Genome Research Institute, Bethesda, Maryland, USA
| | - Michele Nehrebecky
- National Institutes of Health (NIH) Undiagnosed Diseases Program, Common Fund, NIH Office of the Director and National Human Genome Research Institute, Bethesda, Maryland, USA
| | - Grace Park
- Internal Medicine Consult Service, NIH Clinical Center, Bethesda, Maryland, USA
| | - Ariane Soldatos
- National Institutes of Health (NIH) Undiagnosed Diseases Program, Common Fund, NIH Office of the Director and National Human Genome Research Institute, Bethesda, Maryland, USA
| | - Cynthia Tifft
- National Institutes of Health (NIH) Undiagnosed Diseases Program, Common Fund, NIH Office of the Director and National Human Genome Research Institute, Bethesda, Maryland, USA
| | - Camilo Toro
- National Institutes of Health (NIH) Undiagnosed Diseases Program, Common Fund, NIH Office of the Director and National Human Genome Research Institute, Bethesda, Maryland, USA
| | - Colleen Wahl
- National Institutes of Health (NIH) Undiagnosed Diseases Program, Common Fund, NIH Office of the Director and National Human Genome Research Institute, Bethesda, Maryland, USA
| | - Lynne Wolfe
- National Institutes of Health (NIH) Undiagnosed Diseases Program, Common Fund, NIH Office of the Director and National Human Genome Research Institute, Bethesda, Maryland, USA
| | - William A Gahl
- National Institutes of Health (NIH) Undiagnosed Diseases Program, Common Fund, NIH Office of the Director and National Human Genome Research Institute, Bethesda, Maryland, USA
| | - Cornelius F Boerkoel
- National Institutes of Health (NIH) Undiagnosed Diseases Program, Common Fund, NIH Office of the Director and National Human Genome Research Institute, Bethesda, Maryland, USA
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Weeke P, Muhammad R, Delaney JT, Shaffer C, Mosley JD, Blair M, Short L, Stubblefield T, Roden DM, Darbar D. Whole-exome sequencing in familial atrial fibrillation. Eur Heart J 2014; 35:2477-83. [PMID: 24727801 DOI: 10.1093/eurheartj/ehu156] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
AIMS Positional cloning and candidate gene approaches have shown that atrial fibrillation (AF) is a complex disease with familial aggregation. Here, we employed whole-exome sequencing (WES) in AF kindreds to identify variants associated with familial AF. METHODS AND RESULTS WES was performed on 18 individuals in six modestly sized familial AF kindreds. After filtering very rare variants by multiple metrics, we identified 39 very rare and potentially pathogenic variants [minor allele frequency (MAF) ≤0.04%] in genes not previously associated with AF. Despite stringent filtering >1 very rare variants in the 5/6 of the kindreds were identified, whereas no plausible variants contributing to familial AF were found in 1/6 of the kindreds. Two candidate AF variants in the calcium channel subunit genes (CACNB2 and CACNA2D4) were identified in two separate families using expression data and predicted function. CONCLUSION By coupling family data with exome sequencing, we identified multiple very rare potentially pathogenic variants in five of six families, suggestive of a complex disease mechanism, whereas none were identified in the remaining AF pedigree. This study highlights some important limitations and challenges associated with performing WES in AF including the importance of having large well-curated multi-generational pedigrees, the issue of potential AF misclassification, and limitations of WES technology when applied to a complex disease.
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Affiliation(s)
- Peter Weeke
- Division of Clinical Pharmacology, Vanderbilt University, Nashville, TN, USA Department of Cardiology, Copenhagen University Hospital, Gentofte, Denmark
| | - Raafia Muhammad
- Division of Clinical Pharmacology, Vanderbilt University, Nashville, TN, USA
| | - Jessica T Delaney
- Division of Clinical Pharmacology, Vanderbilt University, Nashville, TN, USA
| | - Christian Shaffer
- Division of Clinical Pharmacology, Vanderbilt University, Nashville, TN, USA
| | - Jonathan D Mosley
- Division of Clinical Pharmacology, Vanderbilt University, Nashville, TN, USA
| | - Marcia Blair
- Division of Clinical Pharmacology, Vanderbilt University, Nashville, TN, USA
| | - Laura Short
- Division of Clinical Pharmacology, Vanderbilt University, Nashville, TN, USA
| | - Tanya Stubblefield
- Division of Clinical Pharmacology, Vanderbilt University, Nashville, TN, USA
| | - Dan M Roden
- Division of Clinical Pharmacology, Vanderbilt University, Nashville, TN, USA Division of Cardiovascular Medicine, Vanderbilt University School of Medicine, 2215B Garland Avenue, Room 1285A MRB IV, Nashville 37323-6602, TN, USA
| | - Dawood Darbar
- Division of Clinical Pharmacology, Vanderbilt University, Nashville, TN, USA Division of Cardiovascular Medicine, Vanderbilt University School of Medicine, 2215B Garland Avenue, Room 1285A MRB IV, Nashville 37323-6602, TN, USA
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Salian-Mehta S, Xu M, Knox AJ, Plummer L, Slavov D, Taylor M, Bevers S, Hodges RS, Crowley WF, Wierman ME. Functional consequences of AXL sequence variants in hypogonadotropic hypogonadism. J Clin Endocrinol Metab 2014; 99:1452-60. [PMID: 24476074 PMCID: PMC3973777 DOI: 10.1210/jc.2013-3426] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
CONTEXT Prior studies showed that Axl /Tyro3 null mice have delayed first estrus and abnormal cyclicity due to developmental defects in GnRH neuron migration and survival. OBJECTIVE The objective of the study was to test whether the absence of Axl would alter reproductive function in mice and that mutations in AXL are present in patients with Kallmann syndrome (KS) or normosmic idiopathic hypogonadotropic hypogonadism (nIHH). DESIGN AND SETTING The sexual maturation of Axl null mice was examined. The coding region of AXL was sequenced in 104 unrelated, carefully phenotyped KS or nIHH subjects. Frequency of mutations was compared with other causes of GnRH deficiency. Functional assays were performed on the detected mutations. RESULTS Axl null mice demonstrated delay in first estrus and the interval between vaginal opening and first estrus. Three missense AXL mutations (p.L50F, p.S202C, and p.Q361P) and one intronic variant 6 bp upstream from the start of exon 5 (c.586-6 C>T) were identified in two KS and 2 two nIHH subjects. Comparison of the frequencies of AXL mutations with other putative causes of idiopathic hypogonadotropic hypogonadism confirmed they are rare variants. Testing of the c.586-6 C>T mutation revealed no abnormal splicing. Surface plasmon resonance analysis of the p.L50F, p.S202C, and p.Q361P mutations showed no altered Gas6 ligand binding. In contrast, GT1-7 GnRH neuronal cells expressing p.S202C or p.Q361P demonstrated defective ligand dependent receptor processing and importantly aberrant neuronal migration. In addition, the p.Q361P showed defective ligand independent chemotaxis. CONCLUSIONS Functional consequences of AXL sequence variants in patients with idiopathic hypogonadotropic hypogonadism support the importance of AXL and the Tyro3, Axl, Mer (TAM) family in reproductive development.
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Affiliation(s)
- S Salian-Mehta
- Division of Endocrinology, Metabolism, and Diabetes (S.S.-M., M.X., A.J.K., M.E.W.), Division of Cardiology (D.S., M.T.), and Department of Biochemistry and Molecular Genetics (S.B., R.S.H.), University of Colorado School of Medicine, Aurora, Colorado 80045; Veterans Affairs Research Service (M.E.W.), Veterans Affairs Medical Center, Denver, Colorado 80220; and Harvard Reproductive Endocrine Science Center and the Reproductive Endocrine Unit (L.P., W.F.C.), Department of Medicine, Massachusetts General Hospital, Boston, Massachusetts 02114
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van Spaendonck-Zwarts KY, Posafalvi A, van den Berg MP, Hilfiker-Kleiner D, Bollen IAE, Sliwa K, Alders M, Almomani R, van Langen IM, van der Meer P, Sinke RJ, van der Velden J, Van Veldhuisen DJ, van Tintelen JP, Jongbloed JDH. Titin gene mutations are common in families with both peripartum cardiomyopathy and dilated cardiomyopathy. Eur Heart J 2014; 35:2165-73. [DOI: 10.1093/eurheartj/ehu050] [Citation(s) in RCA: 129] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Morita H. [Cardiomyopathy: progress in diagnosis and treatments topics: I. New classification based on etiology of cardiomyopathy; 2. Genomics of cardiomyopathy]. NIHON NAIKA GAKKAI ZASSHI. THE JOURNAL OF THE JAPANESE SOCIETY OF INTERNAL MEDICINE 2014; 103:285-292. [PMID: 24724368 DOI: 10.2169/naika.103.285] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
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Kapplinger JD, Landstrom AP, Bos JM, Salisbury BA, Callis TE, Ackerman MJ. Distinguishing hypertrophic cardiomyopathy-associated mutations from background genetic noise. J Cardiovasc Transl Res 2014; 7:347-61. [PMID: 24510615 DOI: 10.1007/s12265-014-9542-z] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/24/2013] [Accepted: 01/13/2014] [Indexed: 01/24/2023]
Abstract
Despite the significant progress that has been made in identifying disease-associated mutations, the utility of the hypertrophic cardiomyopathy (HCM) genetic test is limited by a lack of understanding of the background genetic variation inherent to these sarcomeric genes in seemingly healthy subjects. This study represents the first comprehensive analysis of genetic variation in 427 ostensibly healthy individuals for the HCM genetic test using the "gold standard" Sanger sequencing method validating the background rate identified in the publically available exomes. While mutations are clearly overrepresented in disease, a background rate as high as ∼5 % among healthy individuals prevents diagnostic certainty. To this end, we have identified a number of estimated predictive value-based associations including gene-specific, topology, and conservation methods generating an algorithm aiding in the probabilistic interpretation of an HCM genetic test.
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Affiliation(s)
- Jamie D Kapplinger
- Department of Molecular Pharmacology & Experimental Therapeutics, Mayo Clinic, Rochester, MN, USA
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79
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Pugh TJ, Kelly MA, Gowrisankar S, Hynes E, Seidman MA, Baxter SM, Bowser M, Harrison B, Aaron D, Mahanta LM, Lakdawala NK, McDermott G, White ET, Rehm HL, Lebo M, Funke BH. The landscape of genetic variation in dilated cardiomyopathy as surveyed by clinical DNA sequencing. Genet Med 2014; 16:601-8. [DOI: 10.1038/gim.2013.204] [Citation(s) in RCA: 273] [Impact Index Per Article: 24.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
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80
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van Spaendonck-Zwarts KY, van Rijsingen IA, van den Berg MP, Lekanne Deprez RH, Post JG, van Mil AM, Asselbergs FW, Christiaans I, van Langen IM, Wilde AA, de Boer RA, Jongbloed JD, Pinto YM, van Tintelen JP. Genetic analysis in 418 index patients with idiopathic dilated cardiomyopathy: overview of 10 years' experience. Eur J Heart Fail 2014; 15:628-36. [DOI: 10.1093/eurjhf/hft013] [Citation(s) in RCA: 123] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Affiliation(s)
- Karin Y. van Spaendonck-Zwarts
- Department of Genetics, University of Groningen; University Medical Centre Groningen; PO Box 30001 9700 RB Groningen The Netherlands
- Department of Genetics, Academic Medical Centre; University of Amsterdam; The Netherlands
| | | | - Maarten P. van den Berg
- Department of Cardiology, University of Groningen; University Medical Centre Groningen; The Netherlands
| | | | - Jan G. Post
- Department of Medical Genetics, University Medical Centre Utrecht; University of Utrecht; The Netherlands
| | - Anneke M. van Mil
- Department of Genetics, University Medical Centre Leiden; University of Leiden; The Netherlands
| | - Folkert W. Asselbergs
- Department of Cardiology, Heart and Lungs Division; University Medical Centre Utrecht, University of Utrecht; The Netherlands
| | - Imke Christiaans
- Department of Genetics, Academic Medical Centre; University of Amsterdam; The Netherlands
| | - Irene M. van Langen
- Department of Genetics, University of Groningen; University Medical Centre Groningen; PO Box 30001 9700 RB Groningen The Netherlands
| | - Arthur A.M. Wilde
- Department of Cardiology, Academic Medical Centre; University of Amsterdam; The Netherlands
| | - Rudolf A. de Boer
- Department of Cardiology, University of Groningen; University Medical Centre Groningen; The Netherlands
| | - Jan D.H. Jongbloed
- Department of Genetics, University of Groningen; University Medical Centre Groningen; PO Box 30001 9700 RB Groningen The Netherlands
| | - Yigal M. Pinto
- Department of Cardiology, Academic Medical Centre; University of Amsterdam; The Netherlands
| | - J. Peter van Tintelen
- Department of Genetics, University of Groningen; University Medical Centre Groningen; PO Box 30001 9700 RB Groningen The Netherlands
- Durrer Centre for Cardiogenetic Research; Utrecht The Netherlands
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Fatkin D, Seidman CE, Seidman JG. Genetics and disease of ventricular muscle. Cold Spring Harb Perspect Med 2014; 4:a021063. [PMID: 24384818 DOI: 10.1101/cshperspect.a021063] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Cardiomyopathies are a heterogeneous group of heart muscle diseases associated with heart failure, arrhythmias, and death. Genetic variation has a critical role in the pathogenesis of cardiomyopathies, and numerous single-gene mutations have been associated with distinctive cardiomyopathy phenotypes. Contemporaneously with these discoveries, there has been enormous growth of genome-wide sequencing studies in large populations, data that show extensive genomic variation within every individual. The considerable allelic diversity in cardiomyopathy genes and in genes predicted to impact clinical expression of disease mutations indicates the need for a more nuanced interpretation of single-gene mutation in cardiomyopathies. These findings highlight the need to find new ways to interpret the functional significance of suites of genetic variants, as well as the need for new disease models that take global genetic variant burdens, epigenetic factors, and cardiac environmental factors into account.
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Affiliation(s)
- Diane Fatkin
- Molecular Cardiology and Biophysics Division, Victor Chang Cardiac Research Institute, Darlinghurst, New South Wales 2010, Australia
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Cerrone M, Lin X, Zhang M, Agullo-Pascual E, Pfenniger A, Chkourko Gusky H, Novelli V, Kim C, Tirasawadichai T, Judge DP, Rothenberg E, Chen HSV, Napolitano C, Priori SG, Delmar M. Missense mutations in plakophilin-2 cause sodium current deficit and associate with a Brugada syndrome phenotype. Circulation 2013; 129:1092-103. [PMID: 24352520 DOI: 10.1161/circulationaha.113.003077] [Citation(s) in RCA: 261] [Impact Index Per Article: 21.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
BACKGROUND Brugada syndrome (BrS) primarily associates with the loss of sodium channel function. Previous studies showed features consistent with sodium current (INa) deficit in patients carrying desmosomal mutations, diagnosed with arrhythmogenic cardiomyopathy (or arrhythmogenic right ventricular cardiomyopathy). Experimental models showed correlation between the loss of expression of desmosomal protein plakophilin-2 (PKP2) and reduced INa. We hypothesized that PKP2 variants that reduce INa could yield a BrS phenotype, even without overt structural features characteristic of arrhythmogenic right ventricular cardiomyopathy. METHODS AND RESULTS We searched for PKP2 variants in the genomic DNA of 200 patients with a BrS diagnosis, no signs of arrhythmogenic cardiomyopathy, and no mutations in BrS-related genes SCN5A, CACNa1c, GPD1L, and MOG1. We identified 5 cases of single amino acid substitutions. Mutations were tested in HL-1-derived cells endogenously expressing NaV1.5 but made deficient in PKP2 (PKP2-KD). Loss of PKP2 caused decreased INa and NaV1.5 at the site of cell contact. These deficits were restored by the transfection of wild-type PKP2, but not of BrS-related PKP2 mutants. Human induced pluripotent stem cell cardiomyocytes from a patient with a PKP2 deficit showed drastically reduced INa. The deficit was restored by transfection of wild type, but not BrS-related PKP2. Super-resolution microscopy in murine PKP2-deficient cardiomyocytes related INa deficiency to the reduced number of channels at the intercalated disc and increased separation of microtubules from the cell end. CONCLUSIONS This is the first systematic retrospective analysis of a patient group to define the coexistence of sodium channelopathy and genetic PKP2 variations. PKP2 mutations may be a molecular substrate leading to the diagnosis of BrS.
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Affiliation(s)
- Marina Cerrone
- Leon H. Charney Division of Cardiology (M.C., X.L., M.Z., E.A.-P., A.P., H.C.G., S.P., M.D.), and Cardiovascular Genetics Program (M.C., S.P.), NYU School of Medicine, New York, NY; Molecular Cardiology, Maugeri Foundation, Pavia, Italy (V.N., C.N., S.P.); Del E. Webb Center for Neuroscience, Aging & Stem Cell Research, Sanford-Burnham Medical Research Institute, La Jolla, CA (C.K., T.T., H.-S.V.C.); Department of Bioscience and Biotechnology, Sejong University, Seoul, Korea (C.K.); Division of Cardiology, Johns Hopkins University School of Medicine, Baltimore, MD (D.P.J.); and Department of Pharmacology, NYU School of Medicine, New York, NY (E.R.)
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Ganesh SK, Arnett DK, Assimes TL, Basson CT, Chakravarti A, Ellinor PT, Engler MB, Goldmuntz E, Herrington DM, Hershberger RE, Hong Y, Johnson JA, Kittner SJ, McDermott DA, Meschia JF, Mestroni L, O’Donnell CJ, Psaty BM, Vasan RS, Ruel M, Shen WK, Terzic A, Waldman SA. Genetics and Genomics for the Prevention and Treatment of Cardiovascular Disease: Update. Circulation 2013; 128:2813-51. [DOI: 10.1161/01.cir.0000437913.98912.1d] [Citation(s) in RCA: 87] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Mazzanti A, Kanthan A, Monteforte N, Memmi M, Bloise R, Novelli V, Miceli C, O'Rourke S, Borio G, Zienciuk-Krajka A, Curcio A, Surducan AE, Colombo M, Napolitano C, Priori SG. Novel insight into the natural history of short QT syndrome. J Am Coll Cardiol 2013; 63:1300-1308. [PMID: 24291113 PMCID: PMC3988978 DOI: 10.1016/j.jacc.2013.09.078] [Citation(s) in RCA: 147] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/01/2013] [Revised: 09/08/2013] [Accepted: 09/16/2013] [Indexed: 12/21/2022]
Abstract
Objectives This study intends to gain further insights into the natural history, the yield of familial and genetic screening, and the arrhythmogenic mechanisms in the largest cohort of short QT syndrome (SQTS) patients described so far. Background SQTS is a rare genetic disorder associated with life-threatening arrhythmias, and its natural history is incompletely ascertained. Methods Seventy-three SQTS patients (84% male; age, 26 ± 15 years; corrected QT interval, 329 ± 22 ms) were studied, and 62 were followed for 60 ± 41 months (median, 56 months). Results Cardiac arrest (CA) was the most frequent presenting symptom (40% of probands; range, <1 month to 41 years). The rate of CA was 4% in the first year of life and 1.3% per year between 20 and 40 years; the probability of a first occurrence of CA by 40 years of age was 41%. Despite the male predominance, female patients had a risk profile superimposable to that of men (p = 0.49). The yield of genetic screening was low (14%), despite familial disease being present in 44% of kindreds. A history of CA was the only predictor of recurrences at follow-up (p < 0.0000001). Two patterns of onset of ventricular fibrillation were observed and were reproducible in patients with multiple occurrences of CA. Arrhythmias occurred mainly at rest. Conclusions SQTS is highly lethal; CA is often the first manifestation of the disease with a peak incidence in the first year of life. Survivors of CA have a high CA recurrence rate; therefore, implantation of a defibrillator is strongly recommended in this group of patients.
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Affiliation(s)
- Andrea Mazzanti
- Molecular Cardiology, IRCCS Salvatore Maugeri Foundation, Pavia, Italy
| | - Ajita Kanthan
- Molecular Cardiology, IRCCS Salvatore Maugeri Foundation, Pavia, Italy
| | - Nicola Monteforte
- Molecular Cardiology, IRCCS Salvatore Maugeri Foundation, Pavia, Italy
| | - Mirella Memmi
- Molecular Cardiology, IRCCS Salvatore Maugeri Foundation, Pavia, Italy
| | - Raffaella Bloise
- Molecular Cardiology, IRCCS Salvatore Maugeri Foundation, Pavia, Italy
| | - Valeria Novelli
- Molecular Cardiology, IRCCS Salvatore Maugeri Foundation, Pavia, Italy
| | - Carlotta Miceli
- Molecular Cardiology, IRCCS Salvatore Maugeri Foundation, Pavia, Italy
| | - Sean O'Rourke
- Cardiovascular Genetics Program, Leon H. Charney Division of Cardiology, New York University School of Medicine, New York, New York
| | - Gianluca Borio
- Molecular Cardiology, IRCCS Salvatore Maugeri Foundation, Pavia, Italy
| | | | - Antonio Curcio
- Molecular Cardiology, IRCCS Salvatore Maugeri Foundation, Pavia, Italy
| | | | | | - Carlo Napolitano
- Molecular Cardiology, IRCCS Salvatore Maugeri Foundation, Pavia, Italy; Cardiovascular Genetics Program, Leon H. Charney Division of Cardiology, New York University School of Medicine, New York, New York
| | - Silvia G Priori
- Molecular Cardiology, IRCCS Salvatore Maugeri Foundation, Pavia, Italy; Cardiovascular Genetics Program, Leon H. Charney Division of Cardiology, New York University School of Medicine, New York, New York; Department of Molecular Medicine, University of Pavia, Pavia, Italy.
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Abstract
Recent advances have expanded our ability to conduct a comprehensive genetic evaluation for dilated cardiomyopathy (DCM). By evaluating recent literature, this review aims to bring the reader up-to-date on the genetic evaluation of DCM. Updated guidelines have been published. Mutations in BAG3, including a large deletion, were identified in 2 % of DCM. Truncating mutations in TTN were reported in 25 % of DCM. Two new genes have been reported with autosomal recessive DCM. These studies illustrate the role of improved technologies while raising the possibility of a complex genetic model for DCM. The inclusion of TTN has led to an increased genetic testing detection rate of 40 %. While our ability to identify disease-causing variants has increased, so has the identification of variants of unknown significance. A genetic evaluation for DCM must therefore address this complexity.
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86
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Berge KE, Leren TP. Genetics of hypertrophic cardiomyopathy in Norway. Clin Genet 2013; 86:355-60. [PMID: 24111713 DOI: 10.1111/cge.12286] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2013] [Revised: 09/20/2013] [Accepted: 09/20/2013] [Indexed: 11/27/2022]
Abstract
Genetic testing for hypertrophic cardiomyopathy (HCM) became available in Norway in 2003. Here, we describe the results of this testing in probands with HCM referred until the end of 2012. The translated exons of MYBPC3, MYH7, TNNI3, TNNT2, MYL2 and MYL3 were analyzed in two groups of probands. In Group 1, comprising 696 probands above 1 year of age, a mutation was found in 203 patients (29.2%). Of those, 5.9% were carriers of two mutations. Mean age in double mutation carriers, single mutation carriers and mutation negative probands was 44 years (± 19 years), 50 years (± 5 years) and 55 years (± 6 years), respectively. In Group 2, comprising 26 infants below the age of 1, a mutation was found in 15.4%. A total of 120 different mutations were found of which 51 (42.5%) were novel.
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Affiliation(s)
- K E Berge
- Department of Medical Genetics, Oslo University Hospital Ullevaal, Oslo, Norway
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Determining pathogenicity of genetic variants in hypertrophic cardiomyopathy: importance of periodic reassessment. Genet Med 2013; 16:286-93. [PMID: 24113344 DOI: 10.1038/gim.2013.138] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2013] [Accepted: 08/02/2013] [Indexed: 11/08/2022] Open
Abstract
PURPOSE Major advances have been made in our understanding and clinical application of genetic testing in hypertrophic cardiomyopathy. Determining pathogenicity of a single-nucleotide variant remains a major clinical challenge. This study sought to reassess single-nucleotide variant classification in hypertrophic cardiomyopathy probands. METHODS Consecutive probands with hypertrophic cardiomyopathy with a reported pathogenic mutation or variation of uncertain significance were included. Family and medical history were obtained. Each single-nucleotide variant was reassessed by a panel of four reviewers for pathogenicity based on established criteria together with updated cosegregation data and current population-based allele frequencies. RESULTS From 2000 to 2012, a total of 136 unrelated hypertrophic cardiomyopathy probands had genetic testing, of which 63 (46%) carried at least one pathogenic mutation. MYBPC3 (n = 34; 47%) and MYH7 (n = 23; 32%) gene variants together accounted for 79%. Five variants in six probands (10%) were reclassified: two variation of uncertain significance were upgraded to pathogenic, one variation of uncertain significance and one pathogenic variant were downgraded to benign, and one pathogenic variant (found in two families) was downgraded to variation of uncertain significance. None of the reclassifications had any adverse clinical consequences. CONCLUSION Given the rapid growth of genetic information available in both disease and normal populations, periodic reassessment of single-nucleotide variant data is essential in hypertrophic cardiomyopathy.
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Weeke P, Parvez B, Blair M, Short L, Ingram C, Kucera G, Stubblefield T, Roden DM, Darbar D. Candidate gene approach to identifying rare genetic variants associated with lone atrial fibrillation. Heart Rhythm 2013; 11:46-52. [PMID: 24120998 DOI: 10.1016/j.hrthm.2013.10.025] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/23/2013] [Indexed: 10/26/2022]
Abstract
BACKGROUND Rare variants in candidate atrial fibrillation (AF) genes have been associated with AF in small kindreds. The extent to which such polymorphisms contribute to AF is unknown. OBJECTIVE The purpose of this study was to determine the spectrum and prevalence of rare amino acid coding (AAC) variants in candidate AF genes in a large cohort of unrelated lone AF probands. METHODS We resequenced 45 candidate genes in 303 European American (EA) lone AF probands (186 lone AF probands screened for each gene on average [range 89-303], 63 screened for all) identified in the Vanderbilt AF Registry (2002-2012). Variants detected were screened against 4300 EAs from the Exome Sequencing Project (ESP) to identify very rare (minor allele frequency ≤0.04%) AAC variants and these were tested for AF co-segregation in affected family members where possible. RESULTS Median age at AF onset was 46.0 years [interquartile range 33.0-54.0], and 35.6% had a family history of AF. Overall, 63 very rare AAC variants were identified in 60 of 303 lone AF probands, and 10 of 19 (52.6%) had evidence of co-segregation with AF. Among the 63 lone AF probands who had 45 genes screened, the very rare variant burden was 22%. Compared with the 4300 EA ESP, the proportion of lone AF probands with a very rare AAC variant in CASQ2 and NKX2-5 was increased 3-5-fold (P <.05). CONCLUSION No very rare AAC variants were identified in ~80% of lone AF probands. Potential reasons for the lack of very rare AAC variants include a complex pattern of inheritance, variants in as yet unidentified AF genes or in noncoding regions, and environmental factors.
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Affiliation(s)
- Peter Weeke
- Department of Medicine, Vanderbilt University, Nashville, Tennessee; Department of Cardiology, Copenhagen University Hospital, Gentofte, Denmark
| | - Babar Parvez
- Department of Medicine, Vanderbilt University, Nashville, Tennessee
| | - Marcia Blair
- Department of Medicine, Vanderbilt University, Nashville, Tennessee
| | - Laura Short
- Department of Medicine, Vanderbilt University, Nashville, Tennessee
| | - Christie Ingram
- Department of Medicine, Vanderbilt University, Nashville, Tennessee
| | - Gayle Kucera
- Department of Medicine, Vanderbilt University, Nashville, Tennessee
| | | | - Dan M Roden
- Departments of Medicine and Pharmacology, Vanderbilt University, Nashville, Tennessee
| | - Dawood Darbar
- Department of Medicine, Vanderbilt University, Nashville, Tennessee.
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Wilcox AR, Neri PM, Volk LA, Newmark LP, Clark EH, Babb LJ, Varugheese M, Aronson SJ, Rehm HL, Bates DW. A novel clinician interface to improve clinician access to up-to-date genetic results. J Am Med Inform Assoc 2013; 21:e117-21. [PMID: 24013137 DOI: 10.1136/amiajnl-2013-001965] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
OBJECTIVES To understand the impact of GeneInsight Clinic (GIC), a web-based tool designed to manage genetic information and facilitate communication of test results and variant updates from the laboratory to the clinics, we measured the use of GIC and the time it took for new genetic knowledge to be available to clinicians. METHODS Usage data were collected across four study sites for the GIC launch and post-GIC implementation time periods. The primary outcome measures were the time (average number of days) between variant change approval and notification of clinic staff, and the time between notification and viewing the patient record. RESULTS Post-GIC, time between a variant change approval and provider notification was shorter than at launch (average days at launch 503.8, compared to 4.1 days post-GIC). After e-mail alerts were sent at launch, providers clicked into the patient record associated with 91% of these alerts. In the post period, clinic providers clicked into the patient record associated with 95% of the alerts, on average 12 days after the e-mail was sent. DISCUSSION We found that GIC greatly increased the likelihood that a provider would receive updated variant information as well as reduced the time associated with distributing that variant information, thus providing a more efficient process for incorporating new genetic knowledge into clinical care. CONCLUSIONS Our study results demonstrate that health information technology systems have the potential effectively to assist providers in utilizing genetic information in patient care.
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Affiliation(s)
- Allison R Wilcox
- Clinical and Quality Analysis, Partners HealthCare System, Inc, Wellesley, Massachusetts, USA
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90
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Abstract
Remarkable progress has been made in understanding the genetic basis of dilated cardiomyopathy (DCM). Rare variants in >30 genes, some also involved in other cardiomyopathies, muscular dystrophy, or syndromic disease, perturb a diverse set of important myocardial proteins to produce a final DCM phenotype. Large, publicly available datasets have provided the opportunity to evaluate previously identified DCM-causing mutations, and to examine the population frequency of sequence variants similar to those that have been observed to cause DCM. The frequency of these variants, whether associated with dilated or hypertrophic cardiomyopathy, is greater than estimates of disease prevalence. This mismatch might be explained by one or more of the following possibilities: that the penetrance of DCM-causing mutations is lower than previously thought, that some variants are noncausal, that DCM prevalence is higher than previously estimated, or that other more-complex genomics underlie DCM. Reassessment of our assumptions about the complexity of the genomic and phenomic architecture of DCM is warranted. Much about the genomic basis of DCM remains to be investigated, which will require comprehensive genomic studies in much larger cohorts of rigorously phenotyped probands and family members than previously examined.
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91
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92
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Wagner AH, Taylor KR, DeLuca AP, Casavant TL, Mullins RF, Stone EM, Scheetz TE, Braun TA. Prioritization of retinal disease genes: an integrative approach. Hum Mutat 2013; 34:853-9. [PMID: 23508994 DOI: 10.1002/humu.22317] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2012] [Accepted: 03/07/2013] [Indexed: 02/03/2023]
Abstract
The discovery of novel disease-associated variations in genes is often a daunting task in highly heterogeneous disease classes. We seek a generalizable algorithm that integrates multiple publicly available genomic data sources in a machine-learning model for the prioritization of candidates identified in patients with retinal disease. To approach this problem, we generate a set of feature vectors from publicly available microarray, RNA-seq, and ChIP-seq datasets of biological relevance to retinal disease, to observe patterns in gene expression specificity among tissues of the body and the eye, in addition to photoreceptor-specific signals by the CRX transcription factor. Using these features, we describe a novel algorithm, positive and unlabeled learning for prioritization (PULP). This article compares several popular supervised learning techniques as the regression function for PULP. The results demonstrate a highly significant enrichment for previously characterized disease genes using a logistic regression method. Finally, a comparison of PULP with the popular gene prioritization tool ENDEAVOUR shows superior prioritization of retinal disease genes from previous studies. The java source code, compiled binary, assembled feature vectors, and instructions are available online at https://github.com/ahwagner/PULP.
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Affiliation(s)
- Alex H Wagner
- Department of Biomedical Engineering, University of Iowa, Iowa City, Iowa 52242, USA.
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93
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Gonzalez MA, Lebrigio RFA, Van Booven D, Ulloa RH, Powell E, Speziani F, Tekin M, Schüle R, Züchner S. GEnomes Management Application (GEM.app): a new software tool for large-scale collaborative genome analysis. Hum Mutat 2013; 34:842-6. [PMID: 23463597 DOI: 10.1002/humu.22305] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2013] [Accepted: 02/17/2013] [Indexed: 12/13/2022]
Abstract
Novel genes are now identified at a rapid pace for many Mendelian disorders, and increasingly, for genetically complex phenotypes. However, new challenges have also become evident: (1) effectively managing larger exome and/or genome datasets, especially for smaller labs; (2) direct hands-on analysis and contextual interpretation of variant data in large genomic datasets; and (3) many small and medium-sized clinical and research-based investigative teams around the world are generating data that, if combined and shared, will significantly increase the opportunities for the entire community to identify new genes. To address these challenges, we have developed GEnomes Management Application (GEM.app), a software tool to annotate, manage, visualize, and analyze large genomic datasets (https://genomics.med.miami.edu/). GEM.app currently contains ∼1,600 whole exomes from 50 different phenotypes studied by 40 principal investigators from 15 different countries. The focus of GEM.app is on user-friendly analysis for nonbioinformaticians to make next-generation sequencing data directly accessible. Yet, GEM.app provides powerful and flexible filter options, including single family filtering, across family/phenotype queries, nested filtering, and evaluation of segregation in families. In addition, the system is fast, obtaining results within 4 sec across ∼1,200 exomes. We believe that this system will further enhance identification of genetic causes of human disease.
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Affiliation(s)
- Michael A Gonzalez
- Dr. John T. Macdonald Foundation Department of Human Genetics and John P. Hussman Institute for Human Genomics, University of Miami Miller School of Medicine, Miami, Florida, USA
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94
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Mahida S, Hogarth AJ, Cowan C, Tayebjee MH, Graham LN, Pepper CB. Genetics of congenital and drug-induced long QT syndromes: current evidence and future research perspectives. J Interv Card Electrophysiol 2013; 37:9-19. [PMID: 23515882 DOI: 10.1007/s10840-013-9779-5] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/06/2012] [Accepted: 01/07/2013] [Indexed: 12/17/2022]
Abstract
The long QT syndrome (LQTS) is a condition characterized by abnormal prolongation of the QT interval with an associated risk of ventricular arrhythmias and sudden cardiac death. Congenital forms of LQTS arise due to rare and highly penetrant mutations that segregate in a Mendelian fashion. Over the years, multiple mutations in genes encoding ion channels and ion channel binding proteins have been reported to underlie congenital LQTS. Drugs are by far the most common cause of acquired forms of LQTS. Emerging evidence suggests that drug-induced LQTS also has a significant heritable component. However, the genetic substrate underlying drug-induced LQTS is presently largely unknown. In recent years, advances in next-generation sequencing technology and molecular biology techniques have significantly enhanced our ability to identify genetic variants underlying both monogenic diseases and more complex traits. In this review, we discuss the genetic basis of congenital and drug-induced LQTS and focus on future avenues of research in the field. Ultimately, a detailed characterization of the genetic substrate underlying congenital and drug-induced LQTS will enhance risk stratification and potentially result in the development of tailored genotype-based therapies.
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Affiliation(s)
- Saagar Mahida
- Leeds General Infirmary, Great George Street, Leeds, LS1 3EX, UK.
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95
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Lyon GJ, Segal JP. Practical, ethical and regulatory considerations for the evolving medical and research genomics landscape. Appl Transl Genom 2013; 2:34-40. [PMID: 27942444 PMCID: PMC5133337 DOI: 10.1016/j.atg.2013.02.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2012] [Revised: 02/13/2013] [Accepted: 02/13/2013] [Indexed: 01/29/2023]
Abstract
Recent advances in sequencing technology are making possible the application of large-scale genomic analyses to individualized care, both in wellness and disease. However, a number of obstacles remain before genomic sequencing can become a routine part of clinical practice. One of the more significant and underappreciated is the lack of consensus regarding the proper environment and regulatory structure under which clinical genome sequencing and interpretation should be performed. The continued reliance on pure research vs. pure clinical models leads to problems for both research participants and patients in an era in which the lines between research and clinical practice are becoming increasingly blurred. Here, we discuss some of the ethical, regulatory and practical considerations that are emerging in the field of genomic medicine. We also propose that many of the cost and safety issues we are facing can be mitigated through expanded reliance on existing clinical regulatory frameworks and the implementation of distributive work-sharing strategies designed to leverage the strengths of our genomics centers and clinical interpretive teams.
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Affiliation(s)
- Gholson J Lyon
- Stanley Institute for Cognitive Genomics, Cold Spring Harbor Laboratory, NY, United States; Utah Foundation for Biomedical Research, Salt Lake City, UT, United States
| | - Jeremy P Segal
- New York Genome Center, New York City, NY, United States
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96
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Norton N, Li D, Rampersaud E, Morales A, Martin ER, Zuchner S, Guo S, Gonzalez M, Hedges DJ, Robertson PD, Krumm N, Nickerson DA, Hershberger RE. Exome sequencing and genome-wide linkage analysis in 17 families illustrate the complex contribution of TTN truncating variants to dilated cardiomyopathy. ACTA ACUST UNITED AC 2013; 6:144-53. [PMID: 23418287 DOI: 10.1161/circgenetics.111.000062] [Citation(s) in RCA: 89] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
BACKGROUND- Familial dilated cardiomyopathy (DCM) is a genetically heterogeneous disease with >30 known genes. TTN truncating variants were recently implicated in a candidate gene study to cause 25% of familial and 18% of sporadic DCM cases. METHODS AND RESULTS- We used an unbiased genome-wide approach using both linkage analysis and variant filtering across the exome sequences of 48 individuals affected with DCM from 17 families to identify genetic cause. Linkage analysis ranked the TTN region as falling under the second highest genome-wide multipoint linkage peak, multipoint logarithm of odds, 1.59. We identified 6 TTN truncating variants carried by individuals affected with DCM in 7 of 17 DCM families (logarithm of odds, 2.99); 2 of these 7 families also had novel missense variants that segregated with disease. Two additional novel truncating TTN variants did not segregate with DCM. Nucleotide diversity at the TTN locus, including missense variants, was comparable with 5 other known DCM genes. The average number of missense variants in the exome sequences from the DCM cases or the ≈5400 cases from the Exome Sequencing Project was ≈23 per individual. The average number of TTN truncating variants in the Exome Sequencing Project was 0.014 per individual. We also identified a region (chr9q21.11-q22.31) with no known DCM genes with a maximum heterogeneity logarithm of odds score of 1.74. CONCLUSIONS- These data suggest that TTN truncating variants contribute to DCM cause. However, the lack of segregation of all identified TTN truncating variants illustrates the challenge of determining variant pathogenicity even with full exome sequencing.
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Affiliation(s)
- Nadine Norton
- Cardiovascular Division, Department of Medicine, University of Miami Miller School of Medicine, Miami, FL, USA
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97
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Lopes LR, Zekavati A, Syrris P, Hubank M, Giambartolomei C, Dalageorgou C, Jenkins S, McKenna W, Plagnol V, Elliott PM. Genetic complexity in hypertrophic cardiomyopathy revealed by high-throughput sequencing. J Med Genet 2013; 50:228-39. [PMID: 23396983 PMCID: PMC3607113 DOI: 10.1136/jmedgenet-2012-101270] [Citation(s) in RCA: 169] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Background Clinical interpretation of the large number of rare variants identified by high throughput sequencing (HTS) technologies is challenging. The aim of this study was to explore the clinical implications of a HTS strategy for patients with hypertrophic cardiomyopathy (HCM) using a targeted HTS methodology and workflow developed for patients with a range of inherited cardiovascular diseases. By comparing the sequencing results with published findings and with sequence data from a large-scale exome sequencing screen of UK individuals, we sought to quantify the strength of the evidence supporting causality for detected candidate variants. Methods and results 223 unrelated patients with HCM (46±15 years at diagnosis, 74% males) were studied. In order to analyse coding, intronic and regulatory regions of 41 cardiovascular genes, we used solution-based sequence capture followed by massive parallel resequencing on Illumina GAIIx. Average read-depth in the 2.1 Mb target region was 120. Rare (frequency<0.5%) non-synonymous, loss-of-function and splice-site variants were defined as candidates. Excluding titin, we identified 152 distinct candidate variants in sarcomeric or associated genes (89 novel) in 143 patients (64%). Four sarcomeric genes (MYH7, MYBPC3, TNNI3, TNNT2) showed an excess of rare single non-synonymous single-nucleotide polymorphisms (nsSNPs) in cases compared to controls. The estimated probability that a nsSNP in these genes is pathogenic varied between 57% and near certainty depending on the location. We detected an additional 94 candidate variants (73 novel) in desmosomal, and ion-channel genes in 96 patients (43%). Conclusions This study provides the first large-scale quantitative analysis of the prevalence of sarcomere protein gene variants in patients with HCM using HTS technology. Inclusion of other genes implicated in inherited cardiac disease identifies a large number of non-synonymous rare variants of unknown clinical significance.
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Affiliation(s)
- Luis R Lopes
- The Heart Hospital, 16-18 Westmoreland Street, London W1G 8PH, UK.
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98
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Tse HF, Ho JCY, Choi SW, Lee YK, Butler AW, Ng KM, Siu CW, Simpson MA, Lai WH, Chan YC, Au KW, Zhang J, Lay KWJ, Esteban MA, Nicholls JM, Colman A, Sham PC. Patient-specific induced-pluripotent stem cells-derived cardiomyocytes recapitulate the pathogenic phenotypes of dilated cardiomyopathy due to a novel DES mutation identified by whole exome sequencing. Hum Mol Genet 2013; 22:1395-403. [PMID: 23300193 DOI: 10.1093/hmg/dds556] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
In this paper, we report a novel heterozygous mutation of A285V codon conversion on exon 4 of the desmin (DES), using whole exome sequencing (WES) in an isolated proband with documented dilated cardiomyopathy (DCM). This mutation is predicted to cause three-dimensional structure changes of DES. Immunohistological and electron microscopy studies demonstrated diffuse abnormal DES aggregations in DCM-induced-pluripotent stem cell (iPSC)-derived cardiomyocytes, and control-iPSC-derived cardiomyocytes transduced with A285V-DES. DCM-iPSC-derived cardiomyocytes also exhibited functional abnormalities in vitro. This is the first demonstration that patient-specific iPSC-derived cardiomyocytes can be used to provide histological and functional confirmation of a suspected genetic basis for DCM identified by WES.
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Affiliation(s)
- Hung-Fat Tse
- Cardiology Division, Department of Medicine, The University of Hong Kong, Queen Mary Hospital, Hong Kong, China.
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Mestroni L, Taylor MRG. Genetics and genetic testing of dilated cardiomyopathy: a new perspective. DISCOVERY MEDICINE 2013; 15:43-49. [PMID: 23375013 PMCID: PMC3929942] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
The completion of the Human Genome Project was a landmark achievement, but as clinical genetic testing becomes more mainstream, the extent of remarkable genetic variation is increasingly being appreciated. Newer DNA sequencing technology can now complete the sequencing of an entire human genome several times over in a matter of days, but this will undoubtedly add new challenges to the difficulty of distinguishing true pathogenic variants from benign variants in diagnostic genetics and in the research setting. The recent discovery of the role of titin gene (TTN) mutations in dilated cardiomyopathy (DCM) will make genetic testing in this disease more efficient. Furthermore, better understanding of genotype-phenotype associations will assist clinicians in identifying early stages of disease and providing more appropriate treatments. This high level of complexity requires an expert genetic team to offer counseling and to manage, deliver, and follow-up over time the results of genetic testing, which is particularly important for screening of family members potentially at risk. In DCM, genetic testing may be useful for the identification of non-carriers and asymptomatic carriers, as well as for prevention strategies, sport recommendations, and defibrillator implantation. It can also guide reproductive decision-making including utilization of pre-implantation genetic diagnostic strategies.
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Affiliation(s)
- Luisa Mestroni
- Cardiovascular Institute, University of Colorado, Aurora, CO 80305, USA.
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100
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McNally EM, Golbus JR, Puckelwartz MJ. Genetic mutations and mechanisms in dilated cardiomyopathy. J Clin Invest 2013; 123:19-26. [PMID: 23281406 PMCID: PMC3533274 DOI: 10.1172/jci62862] [Citation(s) in RCA: 342] [Impact Index Per Article: 28.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Genetic mutations account for a significant percentage of cardiomyopathies, which are a leading cause of congestive heart failure. In hypertrophic cardiomyopathy (HCM), cardiac output is limited by the thickened myocardium through impaired filling and outflow. Mutations in the genes encoding the thick filament components myosin heavy chain and myosin binding protein C (MYH7 and MYBPC3) together explain 75% of inherited HCMs, leading to the observation that HCM is a disease of the sarcomere. Many mutations are "private" or rare variants, often unique to families. In contrast, dilated cardiomyopathy (DCM) is far more genetically heterogeneous, with mutations in genes encoding cytoskeletal, nucleoskeletal, mitochondrial, and calcium-handling proteins. DCM is characterized by enlarged ventricular dimensions and impaired systolic and diastolic function. Private mutations account for most DCMs, with few hotspots or recurring mutations. More than 50 single genes are linked to inherited DCM, including many genes that also link to HCM. Relatively few clinical clues guide the diagnosis of inherited DCM, but emerging evidence supports the use of genetic testing to identify those patients at risk for faster disease progression, congestive heart failure, and arrhythmia.
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MESH Headings
- Animals
- Arrhythmias, Cardiac/etiology
- Arrhythmias, Cardiac/genetics
- Arrhythmias, Cardiac/metabolism
- Arrhythmias, Cardiac/pathology
- Arrhythmias, Cardiac/physiopathology
- Calcium-Binding Proteins/genetics
- Calcium-Binding Proteins/metabolism
- Cardiac Myosins/genetics
- Cardiac Myosins/metabolism
- Cardiomyopathy, Dilated/complications
- Cardiomyopathy, Dilated/genetics
- Cardiomyopathy, Dilated/metabolism
- Cardiomyopathy, Dilated/pathology
- Cardiomyopathy, Dilated/physiopathology
- Carrier Proteins/genetics
- Carrier Proteins/metabolism
- Cytoskeleton/genetics
- Cytoskeleton/metabolism
- Cytoskeleton/pathology
- Heart Failure/etiology
- Heart Failure/genetics
- Heart Failure/metabolism
- Heart Failure/pathology
- Heart Failure/physiopathology
- Humans
- Mitochondria/genetics
- Mitochondria/metabolism
- Mitochondria/pathology
- Mutation
- Myocardium/metabolism
- Myocardium/pathology
- Myosin Heavy Chains/genetics
- Myosin Heavy Chains/metabolism
- Sarcomeres/genetics
- Sarcomeres/metabolism
- Sarcomeres/pathology
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Affiliation(s)
- Elizabeth M McNally
- Department of Human Genetics, University of Chicago, Chicago, Illinois 60637, USA.
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