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Yu C, Deng XJ, Xu D. Gene mutations in comorbidity of epilepsy and arrhythmia. J Neurol 2023; 270:1229-1248. [PMID: 36376730 DOI: 10.1007/s00415-022-11430-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2022] [Revised: 10/14/2022] [Accepted: 10/15/2022] [Indexed: 11/16/2022]
Abstract
Epilepsy is one of the most common neurological disorders, and sudden unexpected death in epilepsy (SUDEP) is the most severe outcome of refractory epilepsy. Arrhythmia is one of the heterogeneous factors in the pathophysiological mechanism of SUDEP with a high incidence in patients with refractory epilepsy, increasing the risk of premature death. The gene co-expressed in the brain and heart is supposed to be the genetic basis between epilepsy and arrhythmia, among which the gene encoding ion channel contributes to the prevalence of "cardiocerebral channelopathy" theory. Nevertheless, this theory could only explain the molecular mechanism of comorbid arrhythmia in part of patients with epilepsy (PWE). Therefore, we summarized the mutant genes that can induce comorbidity of epilepsy and arrhythmia and the possible corresponding treatments. These variants involved the genes encoding sodium, potassium, calcium and HCN channels, as well as some non-ion channel coding genes such as CHD4, PKP2, FHF1, GNB5, and mitochondrial genes. The relationship between genotype and clinical phenotype was not simple linear. Indeed, genes co-expressed in the brain and heart could independently induce epilepsy and/or arrhythmia. Mutant genes in brain could affect cardiac rhythm through central or peripheral regulation, while in the heart it could also affect cerebral electrical activity by changing the hemodynamics or internal environment. Analysis of mutations in comorbidity of epilepsy and arrhythmia could refine and expand the theory of "cardiocerebral channelopathy" and provide new insights for risk stratification of premature death and corresponding precision therapy in PWE.
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Affiliation(s)
- Cheng Yu
- Department of Neurology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, 1277 Jiefang Avenue, Wuhan, 430022, Hubei Province, China
| | - Xue-Jun Deng
- Department of Neurology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, 1277 Jiefang Avenue, Wuhan, 430022, Hubei Province, China
| | - Da Xu
- Department of Neurology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, 1277 Jiefang Avenue, Wuhan, 430022, Hubei Province, China.
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2
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Kalayinia S, Dalili M, Pourirahim M, Maleki M, Mahdieh N. A novel stop-gain pathogenic variant in the KCNQ1 gene causing long QT syndrome 1. Eur J Med Res 2023; 28:23. [PMID: 36635780 PMCID: PMC9835262 DOI: 10.1186/s40001-023-00984-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2022] [Accepted: 01/02/2023] [Indexed: 01/13/2023] Open
Abstract
BACKGROUND Inherited primary arrhythmias, such as long QT (LQT) syndromes, are electrical abnormalities of the heart mainly due to variants in 3 genes. We herein describe a novel stop-gain pathogenic variant in the KCNQ1 gene in an Iranian child with LQT syndrome 1. METHODS The patient and his family underwent clinical evaluation, electrocardiographic Holter monitoring, and whole-exome sequencing. Sanger sequencing and segregation analysis were used to confirm the variant in the patient and his family, respectively. The pathogenicity of the variant was checked via an in silico analysis. RESULTS The proband suffered from bradycardia and had experienced syncope without stress. The corrected QT interval was 470 ms (the Schwartz score ≥ 3.5), and the Holter monitoring showed sinus rhythm, infrequent premature atrial contractions, and a prolonged QT interval in some leads. Whole-exome and Sanger sequencing showed c.968G > A in 3 affected family members. According to the American College of Medical Genetics and Genomics criteria, c.968G > A was classified as a pathogenic variant. CONCLUSIONS The KCNQ1 gene is the main cause of LQT syndromes in our population. The common genes of LQT syndromes should be studied in our country's different ethnicities to determine the exact role of these genes in these subpopulations.
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Affiliation(s)
- Samira Kalayinia
- grid.411746.10000 0004 4911 7066Cardiogenetic Research Center, Rajaie Cardiovascular Medical and Research Center, Iran University of Medical Sciences, Tehran, Iran
| | - Mohammad Dalili
- grid.411746.10000 0004 4911 7066Rajaie Cardiovascular Medical and Research Center, Iran University of Medical Sciences, Tehran, Iran
| | - Maryam Pourirahim
- grid.411746.10000 0004 4911 7066Cardiogenetic Research Center, Rajaie Cardiovascular Medical and Research Center, Iran University of Medical Sciences, Tehran, Iran
| | - Majid Maleki
- grid.411746.10000 0004 4911 7066Rajaie Cardiovascular Medical and Research Center, Iran University of Medical Sciences, Tehran, Iran
| | - Nejat Mahdieh
- grid.411746.10000 0004 4911 7066Cardiogenetic Research Center, Rajaie Cardiovascular Medical and Research Center, Iran University of Medical Sciences, Tehran, Iran
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3
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Zou X, Wu X, Sampson KJ, Colecraft HM, Larsson HP, Kass RS. Pharmacological rescue of specific long QT variants of KCNQ1/KCNE1 channels. Front Physiol 2022; 13:902224. [PMID: 36505078 PMCID: PMC9726718 DOI: 10.3389/fphys.2022.902224] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Accepted: 11/02/2022] [Indexed: 11/24/2022] Open
Abstract
The congenital Long QT Syndrome (LQTS) is an inherited disorder in which cardiac ventricular repolarization is delayed and predisposes patients to cardiac arrhythmias and sudden cardiac death. LQT1 and LQT5 are LQTS variants caused by mutations in KCNQ1 or KCNE1 genes respectively. KCNQ1 and KCNE1 co-assemble to form critical IKS potassium channels. Beta-blockers are the standard of care for the treatment of LQT1, however, doing so based on mechanisms other than correcting the loss-of-function of K+ channels. ML277 and R-L3 are compounds that enhance IKS channels and slow channel deactivation in a manner that is dependent on the stoichiometry of KCNE1 subunits in the assembled channels. In this paper, we used expression of IKS channels in Chinese hamster ovary (CHO) cells and Xenopus oocytes to study the potential of these two drugs (ML277 and R-L3) for the rescue of LQT1 and LQT5 mutant channels. We focused on the LQT1 mutation KCNQ1-S546L, and two LQT5 mutations, KCNE1-L51H and KCNE1-G52R. We found ML277 and R-L3 potentiated homozygote LQTS mutations in the IKS complexes-KCNE1-G52R and KCNE1-L51H and in heterogeneous IKS channel complexes which mimic heterogeneous expression of mutations in patients. ML277 and R-L3 increased the mutant IKS current amplitude and slowed current deactivation, but not in wild type (WT) IKS. We obtained similar results in the LQT1 mutant (KCNQ1 S546L/KCNE1) with ML277 and R-L3. ML277 and R-L3 had a similar effect on the LQT1 and LQT5 mutants, however, ML277 was more effective than R-L3 in this modulation. Importantly we found that not all LQT5 mutants expressed with KCNQ1 resulted in channels that are potentiated by these drugs as the KCNE1 mutant D76N inhibited drug action when expressed with KCNQ1. Thus, our work shows that by directly studying the treatment of LQT1 and LQT5 mutations with ML277 and R-L3, we will understand the potential utility of these activators as options in specific LQTS therapeutics.
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Affiliation(s)
- Xinle Zou
- Department of Molecular Pharmacology & Therapeutics, Vagelos College of Physicians & Surgeons of Columbia University Irving Medical Center, New York, NY, United States
| | - Xiaoan Wu
- Department of Physiology and Biophysics, Miller School of Medicine, University of Miami, Miami, FL, United States
| | - Kevin J. Sampson
- Department of Molecular Pharmacology & Therapeutics, Vagelos College of Physicians & Surgeons of Columbia University Irving Medical Center, New York, NY, United States
| | - Henry M. Colecraft
- Department of Molecular Pharmacology & Therapeutics, Vagelos College of Physicians & Surgeons of Columbia University Irving Medical Center, New York, NY, United States
| | - H. Peter Larsson
- Department of Physiology and Biophysics, Miller School of Medicine, University of Miami, Miami, FL, United States
| | - Robert S. Kass
- Department of Molecular Pharmacology & Therapeutics, Vagelos College of Physicians & Surgeons of Columbia University Irving Medical Center, New York, NY, United States,*Correspondence: Robert S. Kass,
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4
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Eosinophilic Infiltration of the Sino-Atrial Node in Sudden Cardiac Death Caused by Long QT Syndrome. Int J Mol Sci 2022; 23:ijms231911666. [PMID: 36232963 PMCID: PMC9569895 DOI: 10.3390/ijms231911666] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Revised: 09/25/2022] [Accepted: 09/28/2022] [Indexed: 11/09/2022] Open
Abstract
Sudden death is defined as the unexpected death of a healthy person that occurs within the first hour of the onset of symptoms or within 24 h of the victim being last seen alive. In some of these cases, rare deleterious variants of genes associated with inherited cardiac disorders can provide a highly probable explanation for the fatal event. We report the case of a 21-year-old obese woman who lost consciousness suddenly in a public place and was pronounced dead after hospital admission. Clinical autopsy showed an inconclusive gross examination, while in the histopathological analysis an eosinophilic inflammatory focus and interstitial fibrosis in the sino-atrial node were found. Molecular autopsy revealed an intronic variant in the KCNQ1 gene (c.683 + 5G > A), classified as likely pathogenic for long QT syndrome according to the guidelines provided by the American College of Medical Genetics and Genomics. Therefore, there were many anomalies that could have played a role in the causation of the sudden death, such as the extreme obesity, the cardiac anomalies and the KNCQ1 variant. This case depicts the difficult interpretation of rare cardiac structural abnormalities in subjects carrying rare variants responsible for inherited arrhythmic disorders and the challenge for the forensic pathologist to make causal inferences in the determinism of the unexpected decease.
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5
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Beverley KM, Pattnaik BR. Inward rectifier potassium (Kir) channels in the retina: living our vision. Am J Physiol Cell Physiol 2022; 323:C772-C782. [PMID: 35912989 PMCID: PMC9448332 DOI: 10.1152/ajpcell.00112.2022] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Revised: 07/25/2022] [Accepted: 07/25/2022] [Indexed: 11/22/2022]
Abstract
Channel proteins are vital for conducting ions throughout the body and are especially relevant to retina physiology. Inward rectifier potassium (Kir) channels are a class of K+ channels responsible for maintaining membrane potential and extracellular K+ concentrations. Studies of the KCNJ gene (that encodes Kir protein) expression identified the presence of all of the subclasses (Kir 1-7) of Kir channels in the retina or retinal-pigmented epithelium (RPE). However, functional studies have established the involvement of the Kir4.1 homotetramer and Kir4.1/5.1 heterotetramer in Müller glial cells, Kir2.1 in bipolar cells, and Kir7.1 in the RPE cell physiology. Here, we propose the potential roles of Kir channels in the retina based on the physiological contributions to the brain, pancreatic, and cardiac tissue functions. There are several open questions regarding the expressed KCNJ genes in the retina and RPE. For example, why does not the Kir channel subtype gene expression correspond with protein expression? Catching up with multiomics or functional "omics" approaches might shed light on posttranscriptional changes that might influence Kir subunit mRNA translation within the retina that guides our vision.
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Affiliation(s)
- Katie M Beverley
- Endocrinology and Reproductive Physiology Graduate Program, School of Medicine and Public Health, University of Wisconsin, Madison, Wisconsin
- Department of Pediatrics, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin
- McPherson Eye Research Institute, University of Wisconsin, Madison, Wisconsin
| | - Bikash R Pattnaik
- Endocrinology and Reproductive Physiology Graduate Program, School of Medicine and Public Health, University of Wisconsin, Madison, Wisconsin
- Department of Pediatrics, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin
- McPherson Eye Research Institute, University of Wisconsin, Madison, Wisconsin
- Department of Ophthalmology and Visual Sciences, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin
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6
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Oliveira‐Mendes B, Feliciangeli S, Ménard M, Chatelain F, Alameh M, Montnach J, Nicolas S, Ollivier B, Barc J, Baró I, Schott J, Probst V, Kyndt F, Denjoy I, Lesage F, Loussouarn G, De Waard M. A standardised hERG phenotyping pipeline to evaluate KCNH2 genetic variant pathogenicity. Clin Transl Med 2021; 11:e609. [PMID: 34841674 PMCID: PMC8609418 DOI: 10.1002/ctm2.609] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Revised: 09/22/2021] [Accepted: 09/28/2021] [Indexed: 12/19/2022] Open
Abstract
BACKGROUND AND AIMS Mutations in KCNH2 cause long or short QT syndromes (LQTS or SQTS) predisposing to life-threatening arrhythmias. Over 1000 hERG variants have been described by clinicians, but most remain to be characterised. The objective is to standardise and accelerate the phenotyping process to contribute to clinician diagnosis and patient counselling. In silico evaluation was also included to characterise the structural impact of the variants. METHODS We selected 11 variants from known LQTS patients and two variants for which diagnosis was problematic. Using the Gibson assembly strategy, we efficiently introduced mutations in hERG cDNA despite GC-rich sequences. A pH-sensitive fluorescent tag was fused to hERG for efficient evaluation of channel trafficking. An optimised 35-s patch-clamp protocol was developed to evaluate hERG channel activity in transfected cells. R software was used to speed up analyses. RESULTS In the present work, we observed a good correlation between cell surface expression, assessed by the pH-sensitive tag, and current densities. Also, we showed that the new biophysical protocol allows a significant gain of time in recording ion channel properties and provides extensive information on WT and variant channel biophysical parameters, that can all be recapitulated in a single parameter defined herein as the repolarisation power. The impacts of the variants on channel structure were also reported where structural information was available. These three readouts (trafficking, repolarisation power and structural impact) define three pathogenicity indexes that may help clinical diagnosis. CONCLUSIONS Fast-track characterisation of KCNH2 genetic variants shows its relevance to discriminate mutants that affect hERG channel activity from variants with undetectable effects. It also helped the diagnosis of two new variants. This information is meant to fill a patient database, as a basis for personalised medicine. The next steps will be to further accelerate the process using an automated patch-clamp system.
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Affiliation(s)
| | - Sylvain Feliciangeli
- Labex ICST, Université Côte d'Azur, INSERMCentre National de la Recherche Scientifique, Institut de Pharmacologie Moléculaire et CellulaireValbonneFrance
| | - Mélissa Ménard
- l'Institut du ThoraxInserm UMR 1087/CNRS UMR 6291NantesFrance
| | - Frank Chatelain
- Labex ICST, Université Côte d'Azur, INSERMCentre National de la Recherche Scientifique, Institut de Pharmacologie Moléculaire et CellulaireValbonneFrance
| | - Malak Alameh
- l'Institut du ThoraxInserm UMR 1087/CNRS UMR 6291NantesFrance
| | - Jérôme Montnach
- l'Institut du ThoraxInserm UMR 1087/CNRS UMR 6291NantesFrance
| | | | | | - Julien Barc
- l'Institut du ThoraxInserm UMR 1087/CNRS UMR 6291NantesFrance
| | - Isabelle Baró
- l'Institut du ThoraxInserm UMR 1087/CNRS UMR 6291NantesFrance
| | | | - Vincent Probst
- CHU Nantes, l'Institut du Thorax, INSERM, CNRSUNIV NantesNantesFrance
| | - Florence Kyndt
- CHU Nantes, l'Institut du Thorax, INSERM, CNRSUNIV NantesNantesFrance
| | - Isabelle Denjoy
- Service de Cardiologie et CNMR Maladies Cardiaques Héréditaires RaresHôpital BichatParisFrance
| | - Florian Lesage
- Labex ICST, Université Côte d'Azur, INSERMCentre National de la Recherche Scientifique, Institut de Pharmacologie Moléculaire et CellulaireValbonneFrance
| | | | - Michel De Waard
- l'Institut du ThoraxInserm UMR 1087/CNRS UMR 6291NantesFrance
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7
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He S, Moutaoufik MT, Islam S, Persad A, Wu A, Aly KA, Fonge H, Babu M, Cayabyab FS. HERG channel and cancer: A mechanistic review of carcinogenic processes and therapeutic potential. Biochim Biophys Acta Rev Cancer 2020; 1873:188355. [PMID: 32135169 DOI: 10.1016/j.bbcan.2020.188355] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2019] [Revised: 02/28/2020] [Accepted: 02/28/2020] [Indexed: 12/21/2022]
Abstract
The human ether-à-go-go related gene (HERG) encodes the alpha subunit of Kv11.1, which is a voltage-gated K+ channel protein mainly expressed in heart and brain tissue. HERG plays critical role in cardiac repolarization, and mutations in HERG can cause long QT syndrome. More recently, evidence has emerged that HERG channels are aberrantly expressed in many kinds of cancer cells and play important roles in cancer progression. HERG could therefore be a potential biomarker for cancer and a possible molecular target for anticancer drug design. HERG affects a number of cellular processes, including cell proliferation, apoptosis, angiogenesis and migration, any of which could be affected by dysregulation of HERG. This review provides an overview of available information on HERG channel as it relates to cancer, with focus on the mechanism by which HERG influences cancer progression. Molecular docking attempts suggest two possible protein-protein interactions of HERG with the ß1-integrin receptor and the transcription factor STAT-1 as novel HERG-directed therapeutic targeting which avoids possible cardiotoxicity. The role of epigenetics in regulating HERG channel expression and activity in cancer will also be discussed. Finally, given its inherent extracellular accessibility as an ion channel, we discuss regulatory roles of this molecule in cancer physiology and therapeutic potential. Future research should be directed to explore the possibilities of therapeutic interventions targeting HERG channels while minding possible complications.
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Affiliation(s)
- Siyi He
- Department of Surgery, Neuroscience Research Group, College of Medicine, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E5, Canada
| | | | - Saadul Islam
- Department of Surgery, Neuroscience Research Group, College of Medicine, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E5, Canada
| | - Amit Persad
- Department of Surgery, Neuroscience Research Group, College of Medicine, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E5, Canada
| | - Adam Wu
- Department of Surgery, Neuroscience Research Group, College of Medicine, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E5, Canada
| | - Khaled A Aly
- Department of Biochemistry, University of Regina, Regina, SK S4S 0A2, Canada
| | - Humphrey Fonge
- Department of Medical Imaging, University of Saskatchewan, Saskatoon, Saskatchewan S7N 0W8, Canada; Department of Medical Imaging, Royal University Hospital, Saskatoon, Saskatchewan S7N 0W8, Canada
| | - Mohan Babu
- Department of Biochemistry, University of Regina, Regina, SK S4S 0A2, Canada
| | - Francisco S Cayabyab
- Department of Surgery, Neuroscience Research Group, College of Medicine, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E5, Canada.
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8
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9
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Bennett JS, Bernhardt M, McBride KL, Reshmi SC, Zmuda E, Kertesz NJ, Garg V, Fitzgerald-Butt S, Kamp AN. Reclassification of Variants of Uncertain Significance in Children with Inherited Arrhythmia Syndromes is Predicted by Clinical Factors. Pediatr Cardiol 2019; 40:1679-1687. [PMID: 31535183 DOI: 10.1007/s00246-019-02203-2] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/30/2019] [Accepted: 08/28/2019] [Indexed: 12/19/2022]
Abstract
Genetic testing is important to augment clinical diagnosis and inform management of inherited arrhythmias syndromes (IAS), but variants of uncertain significance (VUS) are common and remain a challenge in clinical practice. In 2015, American College of Medical Genetics (ACMG) published updated guidelines for interpretation of genetic results. Despite increasing understanding of human genomic variation, there are no guidelines for reinterpretation of prior genetic test results. Patients at a single tertiary children's hospital with genetic testing for an IAS that demonstrated a VUS were re-evaluated using 2015 ACMG guidelines, clinical information, and publically available databases. Search of the electronic medical record identified 116 patients with genetic testing results available, and 24/116 (21%) harbored a VUS for an IAS. 23 unique VUS were evaluated from 12 genes. Over half of the VUS (12/23 (52%)) were reclassified using 2015 criteria, and 8 (35%) changed to pathogenic and 4 (17%) to benign. Relative risk of reclassification of VUS to a pathogenic variant in a patient with confirmed clinical diagnosis was 4.1 (95% CI 1.23-15.4). Reclassification was not associated with initial testing year. These data demonstrate 52% of VUS in children with IAS are reclassified with application of 2015 ACMG guidelines. Strength of phenotyping is associated with eventual pathogenic classification of genetic variants and periodic re-evaluation of VUS identified on genetic testing for IAS is warranted.
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Affiliation(s)
- Jeffrey S Bennett
- Department of Pediatrics, The Ohio State University College of Medicine, Columbus, OH, USA.,The Heart Center, Nationwide Children's Hospital, 700 Children's Drive, Columbus, OH, 43205, USA
| | - Madison Bernhardt
- Department of Medical Genetics, St. Luke's Mountain States Tumor Institute, Boise, ID, USA
| | - Kim L McBride
- Department of Pediatrics, The Ohio State University College of Medicine, Columbus, OH, USA.,Division of Genetic and Genomic Medicine, Nationwide Children's Hospital, Columbus, OH, USA.,The Center for Cardiovascular Research, Nationwide Children's Hospital, Columbus, OH, USA
| | - Shalini C Reshmi
- Department of Pediatrics, The Ohio State University College of Medicine, Columbus, OH, USA.,Department of Pathology and Laboratory Medicine, Nationwide Children's Hospital, Columbus, OH, USA
| | - Erik Zmuda
- Department of Pediatrics, The Ohio State University College of Medicine, Columbus, OH, USA.,Department of Pathology and Laboratory Medicine, Nationwide Children's Hospital, Columbus, OH, USA
| | - Naomi J Kertesz
- Department of Pediatrics, The Ohio State University College of Medicine, Columbus, OH, USA.,The Heart Center, Nationwide Children's Hospital, 700 Children's Drive, Columbus, OH, 43205, USA
| | - Vidu Garg
- Department of Pediatrics, The Ohio State University College of Medicine, Columbus, OH, USA.,The Heart Center, Nationwide Children's Hospital, 700 Children's Drive, Columbus, OH, 43205, USA.,The Center for Cardiovascular Research, Nationwide Children's Hospital, Columbus, OH, USA
| | - Sara Fitzgerald-Butt
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Anna N Kamp
- Department of Pediatrics, The Ohio State University College of Medicine, Columbus, OH, USA. .,The Heart Center, Nationwide Children's Hospital, 700 Children's Drive, Columbus, OH, 43205, USA.
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10
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Marschall C, Moscu-Gregor A, Klein HG. Variant panorama in 1,385 index patients and sensitivity of expanded next-generation sequencing panels in arrhythmogenic disorders. Cardiovasc Diagn Ther 2019; 9:S292-S298. [PMID: 31737537 DOI: 10.21037/cdt.2019.06.06] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Background Arrhythmogenic disorders occur in a broad spectrum of cardiac pathologies in the general population with a prevalence of 1:10,000 to 1:500. Genetic studies conducted during the past 20 years have markedly illuminated the genetic basis of inherited cardiac disorders. However, uncertainty exists regarding which genes should be included and routinely assessed on genetic testing panels. Here, we review the genetic basis of the most important arrhythmogenic disorders found in our laboratory since 2016 by next-generation sequencing (NGS) analysis. Methods We analyzed sequence data from 1,385 clinical index cases with a suspected diagnosis of long QT syndrome (LQTS), Brugada syndrome (BrS), catecholaminergic polymorphic ventricular tachycardia (CPVT), hypertrophic cardiomyopathy (HCM), dilatative cardiomyopathy (DCM) or arrhythmogenic right ventricular cardiomyopathy (ARVC). Genetic testing was performed by NGS using a custom design based on an Agilent SureSelectQXT. Results The detection rate of pathogenic or likely pathogenic variants was in the range of 16% for BrS to 40% for HCM. Only the few well known core genes and some additional side genes substantially contribute to the diagnostic sensitivity. Conclusions Clinical testing provides a definitive diagnosis for many patients. The genetic result may be important for risk stratification, genetic counseling and, in some cases, treatment planning. Diagnostic panels should not be further expanded as inclusion of many genes rather produces variants of unclear significance and confusing reports.
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Affiliation(s)
| | | | - Hanns-Georg Klein
- Center for Human Genetics and Laboratory Diagnostics, Martinsried, Germany
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11
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Faridi R, Tona R, Brofferio A, Hoa M, Olszewski R, Schrauwen I, Assir MZ, Bandesha AA, Khan AA, Rehman AU, Brewer C, Ahmed W, Leal SM, Riazuddin S, Boyden SE, Friedman TB. Mutational and phenotypic spectra of KCNE1 deficiency in Jervell and Lange-Nielsen Syndrome and Romano-Ward Syndrome. Hum Mutat 2019; 40:162-176. [PMID: 30461122 PMCID: PMC6328321 DOI: 10.1002/humu.23689] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2018] [Revised: 11/01/2018] [Accepted: 11/15/2018] [Indexed: 11/11/2022]
Abstract
KCNE1 encodes a regulatory subunit of the KCNQ1 potassium channel-complex. Both KCNE1 and KCNQ1 are necessary for normal hearing and cardiac ventricular repolarization. Recessive variants in these genes are associated with Jervell and Lange-Nielson syndrome (JLNS1 and JLNS2), a cardio-auditory syndrome characterized by congenital profound sensorineural deafness and a prolonged QT interval that can cause ventricular arrhythmias and sudden cardiac death. Some normal-hearing carriers of heterozygous missense variants of KCNE1 and KCNQ1 have prolonged QT intervals, a dominantly inherited phenotype designated Romano-Ward syndrome (RWS), which is also associated with arrhythmias and elevated risk of sudden death. Coassembly of certain mutant KCNE1 monomers with wild-type KCNQ1 subunits results in RWS by a dominant negative mechanism. This paper reviews variants of KCNE1 and their associated phenotypes, including biallelic truncating null variants of KCNE1 that have not been previously reported. We describe three homozygous nonsense mutations of KCNE1 segregating in families ascertained ostensibly for nonsyndromic deafness: c.50G>A (p.Trp17*), c.51G>A (p.Trp17*), and c.138C>A (p.Tyr46*). Some individuals carrying missense variants of KCNE1 have RWS. However, heterozygotes for loss-of-function variants of KCNE1 may have normal QT intervals while biallelic null alleles are associated with JLNS2, indicating a complex genotype-phenotype spectrum for KCNE1 variants.
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Affiliation(s)
- Rabia Faridi
- Laboratory of Molecular Genetics, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD 20892, USA
- National Centre of Excellence in Molecular Biology, University of the Punjab, Lahore 54550, Pakistan
| | - Risa Tona
- Laboratory of Molecular Genetics, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD 20892, USA
| | - Alessandra Brofferio
- Cardiology Branch, National Heart, Lung, and Blood Institute, National Institutes of Health Clinical Center, Bethesda, MD 20892, USA
| | - Michael Hoa
- Auditory Development and Restoration Program, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD 20892, USA
| | - Rafal Olszewski
- Auditory Development and Restoration Program, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD 20892, USA
| | - Isabelle Schrauwen
- Center for Statistical Genetics, Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Muhammad Z.K. Assir
- Allama Iqbal Medical Research Centre, Jinnah Hospital Complex, Lahore 54550, Pakistan
| | - Akhtar A. Bandesha
- Cardiology Department, The Pakistan Institute of Medical Sciences, Islamabad, Pakistan
| | - Asma A. Khan
- National Centre of Excellence in Molecular Biology, University of the Punjab, Lahore 54550, Pakistan
| | - Atteeq U. Rehman
- Laboratory of Molecular Genetics, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD 20892, USA
| | - Carmen Brewer
- Audiology Unit, National Institute on Deafness and Other Communication Disorders (NIDCD), National Institutes of Health, Bethesda, MD 20892, USA
| | - Wasim Ahmed
- Department of Biochemistry, Faculty of Biological Sciences, Quaid-i-Azam University, Islamabad 45320, Pakistan
| | - Suzanne M. Leal
- Center for Statistical Genetics, Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Sheikh Riazuddin
- Allama Iqbal Medical Research Centre, Jinnah Hospital Complex, Lahore 54550, Pakistan
| | - Steven E. Boyden
- Section on Genetics of Communication Disorders, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD 20892, USA
| | - Thomas B. Friedman
- Laboratory of Molecular Genetics, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD 20892, USA
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12
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Seo SH, Kim SY, Cho SI, Park H, Lee S, Choi JM, Kim MJ, Lee JS, Ahn KJ, Song MK, Bae EJ, Park SS, Seong MW. Application of Multigene Panel Sequencing in Patients with Prolonged Rate-corrected QT Interval and No Pathogenic Variants Detected in KCNQ1, KCNH2, and SCN5A. Ann Lab Med 2018; 38:54-58. [PMID: 29071820 PMCID: PMC5700148 DOI: 10.3343/alm.2018.38.1.54] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2017] [Revised: 06/29/2017] [Accepted: 09/14/2017] [Indexed: 01/08/2023] Open
Abstract
Long QT syndrome (LQTS) is an inherited cardiac disease characterized by a prolonged heart rate-corrected QT (QTc) interval. We investigated the genetic causes in patients with prolonged QTc intervals who were negative for pathogenic variants in three major LQTS-related genes (KCNQ1, KCNH2, and SCN5A). Molecular genetic testing was performed using a panel including 13 LQTS-related genes and 67 additional genes implicated in other cardiac diseases. Overall, putative genetic causes of prolonged QTc interval were identified in three of the 30 patients (10%). Among the LQTS-related genes, we detected a previously reported pathogenic variant, CACNA1C c.1552C>T, responsible for cardiac-only Timothy syndrome. Among the genes related to other cardiac diseases, a likely pathogenic variant, RYR2 c.11995A>G, was identified in a patient with catecholaminergic polymorphic ventricular tachycardia. Another patient who developed dilated cardiomyopathy with prolonged QTc interval was found to carry a likely pathogenic variant, TAZ c.718G>A, associated with infantile dilated cardiomyopathy. Comprehensive screening of genetic variants using multigene panel sequencing enables detection of genetic variants with a possible involvement in QTc interval prolongation, thus uncovering unknown molecular mechanisms underlying LQTS.
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Affiliation(s)
- Soo Hyun Seo
- Department of Laboratory Medicine, Seoul National University Bundang Hospital, Seongnam, Korea
| | - So Yeon Kim
- Department of Laboratory Medicine, National Medical Center, Seoul, Korea
| | - Sung Im Cho
- Department of Laboratory Medicine, Seoul National University Hospital, Seoul National University College of Medicine, Seoul, Korea
| | - Hyunwoong Park
- Department of Laboratory Medicine, Gyeongsang National University Changwon Hospital, Changwon, Korea
| | - Seungjun Lee
- Department of Laboratory Medicine, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul, Korea
| | - Jong Moon Choi
- Green Cross Genome, Yongin, Korea.,Green Cross Laboratories, Yongin, Korea
| | - Man Jin Kim
- Department of Laboratory Medicine, Seoul National University Hospital, Seoul National University College of Medicine, Seoul, Korea
| | - Jee Soo Lee
- Department of Laboratory Medicine, Hallym University Sacred Heart Hospital, Anyang, Korea
| | - Kyung Jin Ahn
- Department of Pediatrics, Seoul National University Children's Hospital, Seoul National University College of Medicine, Seoul, Korea
| | - Mi Kyoung Song
- Department of Pediatrics, Seoul National University Children's Hospital, Seoul National University College of Medicine, Seoul, Korea
| | - Eun Jung Bae
- Department of Pediatrics, Seoul National University Children's Hospital, Seoul National University College of Medicine, Seoul, Korea
| | - Sung Sup Park
- Department of Laboratory Medicine, Seoul National University Hospital, Seoul National University College of Medicine, Seoul, Korea
| | - Moon Woo Seong
- Department of Laboratory Medicine, Seoul National University Hospital, Seoul National University College of Medicine, Seoul, Korea.
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Landstrom AP, Fernandez E, Rosenfeld JA, Yang Y, Dailey-Schwartz AL, Miyake CY, Allen HD, Penny DJ, Kim JJ. Amino acid-level signal-to-noise analysis of incidentally identified variants in genes associated with long QT syndrome during pediatric whole exome sequencing reflects background genetic noise. Heart Rhythm 2018; 15:1042-1050. [PMID: 29501670 DOI: 10.1016/j.hrthm.2018.02.031] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/04/2018] [Indexed: 10/17/2022]
Abstract
BACKGROUND Due to rapid expansion of clinical genetic testing, an increasing number of genetic variants of undetermined significance and unclear diagnostic value are being identified in children. Variants found in genes associated with heritable channelopathies, such as long QT syndrome (LQTS), are particularly difficult to interpret given the risk of sudden cardiac death associated with pathologic mutations. OBJECTIVE The purpose of this study was to determine whether variants in LQTS-associated genes from whole exome sequencing (WES) represent disease-associated biomarkers or background genetic "noise." METHODS WES variants from Baylor Genetics Laboratories were obtained for 17 LQTS-associated genes. Rare variants from healthy controls were obtained from the GnomAD database. LQTS case variants were extracted from the literature. Amino acid-level mapping and signal-to-noise calculations were conducted. Clinical history and diagnostic studies were analyzed for WES subjects evaluated at our institution. RESULTS Variants in LQTS case-associated genes were present in 38.3% of 7244 WES probands. There was a similar frequency of variants in the WES and healthy cohorts for LQTS1-3 (11.2% and 12.9%, respectively) and LQTS4-17 (27.1% and 38.4%, respectively). WES variants preferentially localized to amino acids altered in control individuals compared to cases. Based on amino acid-level analysis, WES-identified variants are indistinguishable from healthy background variation, whereas LQTS1 and 2 case-identified variants localized to clear pathologic "hotspots." No individuals who underwent clinical evaluation had clinical suspicion for LQTS. CONCLUSION The prevalence of incidentally identified LQTS-associated variants is ∼38% among WES tests. These variants most likely represent benign healthy background genetic variation rather than disease-associated mutations.
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Affiliation(s)
- Andrew P Landstrom
- Department of Pediatrics, Section of Pediatric Cardiology, Baylor College of Medicine, Houston, Texas.
| | - Ernesto Fernandez
- Department of Pediatrics, Section of Pediatric Cardiology, Baylor College of Medicine, Houston, Texas
| | | | - Yaping Yang
- Baylor Miraca Genetic Laboratories, Houston, Texas
| | - Andrew L Dailey-Schwartz
- Department of Pediatrics, Section of Pediatric Cardiology, Baylor College of Medicine, Houston, Texas
| | - Christina Y Miyake
- Department of Pediatrics, Section of Pediatric Cardiology, Baylor College of Medicine, Houston, Texas
| | - Hugh D Allen
- Department of Pediatrics, Section of Pediatric Cardiology, Baylor College of Medicine, Houston, Texas
| | - Daniel J Penny
- Department of Pediatrics, Section of Pediatric Cardiology, Baylor College of Medicine, Houston, Texas
| | - Jeffrey J Kim
- Department of Pediatrics, Section of Pediatric Cardiology, Baylor College of Medicine, Houston, Texas
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14
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Kaltman JR, Evans F, Fu YP. Re-evaluating pathogenicity of variants associated with the long QT syndrome. J Cardiovasc Electrophysiol 2017; 29:98-104. [PMID: 28988457 DOI: 10.1111/jce.13355] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/05/2017] [Revised: 08/17/2017] [Accepted: 09/11/2017] [Indexed: 01/06/2023]
Abstract
INTRODUCTION Genetic testing for congenital long QT syndrome (LQTS) has become common. Recent studies have shown that some variants labelled as pathogenic might be misclassified due to sparse case reports and relatively common allele frequencies (AF) in the general population. This study aims to evaluate the presence of LQTS-associated variants in the Genome Aggregation Database (gnomAD) population, and assess the functional impact of these variants. METHODS AND RESULTS Variants associated with LQTS from the Human Gene Mutation Database were extracted and matched to the gnomAD to evaluate population-based AF. We used MetaSVM to predict the function of LQTS variants. Allele distribution by protein topology in KCNQ1, KCNH2, and SCN5A was compared between gnomAD (n = 123,136) and a cohort of LQTS patients aggregated from eight published studies (n = 2,683). Among the 1,415 LQTS-associated single nucleotide variants in 30 genes, 347 (25%) are present in gnomAD; 24% of the 347 variants were predicted as functionally tolerated compared with 4% of variants not present in gnomAD (P < 0.001). Of the 347 pathogenic variants in gnomAD, seven (2%) had an AF of ≥ 0.001 and 65 (19%) variants had an AF of ≥ 0.0001. In KCNQ1, KCNH2, and SCN5A, allele distribution by protein functional region was significantly different with gnomAD alleles appearing less frequently in highly pathogenic domains than case alleles. CONCLUSION A significant number of LQTS variants have insufficient evidence for pathogenicity and relatively common AF in the general population. Caution should be used when ascribing pathogenicity to these variants.
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Affiliation(s)
- Jonathan R Kaltman
- Division of Cardiovascular Sciences, National Heart, Lung, and Blood Institute, Bethesda, MD, USA
| | - Frank Evans
- Division of Cardiovascular Sciences, National Heart, Lung, and Blood Institute, Bethesda, MD, USA
| | - Yi-Ping Fu
- Division of Cardiovascular Sciences, National Heart, Lung, and Blood Institute, Bethesda, MD, USA
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15
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Wang B, Guo RQ, Wang J, Yang F, Zuo L, Liu Y, Shao H, Ju Y, Sun C, Xu L, Zhang YM, Wang LF, Liu LW. The Cumulative Effects of the MYH7-V878A and CACNA1C-A1594V Mutations in a Chinese Family with Hypertrophic Cardiomyopathy. Cardiology 2017; 138:228-237. [PMID: 28866666 DOI: 10.1159/000478900] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/16/2017] [Accepted: 06/21/2017] [Indexed: 01/05/2023]
Abstract
AIMS We investigated the pathogenesis of MYH7-V878A and CACNA1C-A1594V mutations in a Chinese family with hypertrophic cardiomyopathy. METHODS Clinical, electrocardiographic (ECG), echocardiographic, and cardiac magnetic resonance (CMR) examinations of members of a Chinese family were followed by exon and boarding intron analyses of 96 genes in the proband using second-generation sequencing. We confirmed the mutations by bidirectional Sanger sequencing in the members and in 300 healthy controls. RESULTS We detected MYH7-V878A and CACNA1C-A1594V mutations in this family. The members with both mutations showed inverted T-waves and ST-segment depression in ECG recordings, severe left ventricular (LV) hypertrophy in echocardiography, and myocardial fibrosis in CMR; subject II-11 did not show late gadolinium enhancement. Among those with only the MYH7-V878A mutation, subject III-7 showed abnormal ECG recordings, asymmetric septal hypertrophy, and myocardial fibrosis, and subjects II-13 and III-15 showed some abnormal repolarization, borderline LV wall thickness, and normal CMR findings. Those with only the CACNA1C-A1594V mutation showed nearly normal readings in all examinations. The members with both mutations displayed more severe LV hypertrophy and elevated LV filling pressure than those with 1 or no mutation (p < 0.05). CONCLUSION Our results suggest that the pathogenesis of MYH7-V878A and CACNA1C-A1594V mutations may have a cumulative effect.
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Affiliation(s)
- Bo Wang
- Department of Ultrasound, Xijing Hospital, Fourth Military Medical University, Xi'an, China
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16
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Roberts JD, Krahn AD, Ackerman MJ, Rohatgi RK, Moss AJ, Nazer B, Tadros R, Gerull B, Sanatani S, Wijeyeratne YD, Baruteau AE, Muir AR, Pang B, Cadrin-Tourigny J, Talajic M, Rivard L, Tester DJ, Liu T, Whitman IR, Wojciak J, Conacher S, Gula LJ, Leong-Sit P, Manlucu J, Green MS, Hamilton R, Healey JS, Lopes CM, Behr ER, Wilde AA, Gollob MH, Scheinman MM. Loss-of-Function
KCNE2
Variants. Circ Arrhythm Electrophysiol 2017; 10:CIRCEP.117.005282. [DOI: 10.1161/circep.117.005282] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/09/2017] [Accepted: 06/29/2017] [Indexed: 11/16/2022]
Affiliation(s)
| | | | | | | | | | - Babak Nazer
- For author affiliations, please see the Appendix
| | - Rafik Tadros
- For author affiliations, please see the Appendix
| | | | | | | | | | | | | | | | | | - Lena Rivard
- For author affiliations, please see the Appendix
| | | | - Taylor Liu
- For author affiliations, please see the Appendix
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17
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Abstract
Somatic mosaicism, the occurrence and propagation of genetic variation in cell lineages after fertilization, is increasingly recognized to play a causal role in a variety of human diseases. We investigated the case of life-threatening arrhythmia in a 10-day-old infant with long QT syndrome (LQTS). Rapid genome sequencing suggested a variant in the sodium channel NaV1.5 encoded by SCN5A, NM_000335:c.5284G > T predicting p.(V1762L), but read depth was insufficient to be diagnostic. Exome sequencing of the trio confirmed read ratios inconsistent with Mendelian inheritance only in the proband. Genotyping of single circulating leukocytes demonstrated the mutation in the genomes of 8% of patient cells, and RNA sequencing of cardiac tissue from the infant confirmed the expression of the mutant allele at mosaic ratios. Heterologous expression of the mutant channel revealed significantly delayed sodium current with a dominant negative effect. To investigate the mechanism by which mosaicism might cause arrhythmia, we built a finite element simulation model incorporating Purkinje fiber activation. This model confirmed the pathogenic consequences of cardiac cellular mosaicism and, under the presenting conditions of this case, recapitulated 2:1 AV block and arrhythmia. To investigate the extent to which mosaicism might explain undiagnosed arrhythmia, we studied 7,500 affected probands undergoing commercial gene-panel testing. Four individuals with pathogenic variants arising from early somatic mutation events were found. Here we establish cardiac mosaicism as a causal mechanism for LQTS and present methods by which the general phenomenon, likely to be relevant for all genetic diseases, can be detected through single-cell analysis and next-generation sequencing.
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18
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Priest JR, Osoegawa K, Mohammed N, Nanda V, Kundu R, Schultz K, Lammer EJ, Girirajan S, Scheetz T, Waggott D, Haddad F, Reddy S, Bernstein D, Burns T, Steimle JD, Yang XH, Moskowitz IP, Hurles M, Lifton RP, Nickerson D, Bamshad M, Eichler EE, Mital S, Sheffield V, Quertermous T, Gelb BD, Portman M, Ashley EA. De Novo and Rare Variants at Multiple Loci Support the Oligogenic Origins of Atrioventricular Septal Heart Defects. PLoS Genet 2016; 12:e1005963. [PMID: 27058611 PMCID: PMC4825975 DOI: 10.1371/journal.pgen.1005963] [Citation(s) in RCA: 72] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2015] [Accepted: 03/07/2016] [Indexed: 12/15/2022] Open
Abstract
Congenital heart disease (CHD) has a complex genetic etiology, and recent studies suggest that high penetrance de novo mutations may account for only a small fraction of disease. In a multi-institutional cohort surveyed by exome sequencing, combining analysis of 987 individuals (discovery cohort of 59 affected trios and 59 control trios, and a replication cohort of 100 affected singletons and 533 unaffected singletons) we observe variation at novel and known loci related to a specific cardiac malformation the atrioventricular septal defect (AVSD). In a primary analysis, by combining developmental coexpression networks with inheritance modeling, we identify a de novo mutation in the DNA binding domain of NR1D2 (p.R175W). We show that p.R175W changes the transcriptional activity of Nr1d2 using an in vitro transactivation model in HUVEC cells. Finally, we demonstrate previously unrecognized cardiovascular malformations in the Nr1d2tm1-Dgen knockout mouse. In secondary analyses we map genetic variation to protein-interaction networks suggesting a role for two collagen genes in AVSD, which we corroborate by burden testing in a second replication cohort of 100 AVSDs and 533 controls (p = 8.37e-08). Finally, we apply a rare-disease inheritance model to identify variation in genes previously associated with CHD (ZFPM2, NSD1, NOTCH1, VCAN, and MYH6), cardiac malformations in mouse models (ADAM17, CHRD, IFT140, PTPRJ, RYR1 and ATE1), and hypomorphic alleles of genes causing syndromic CHD (EHMT1, SRCAP, BBS2, NOTCH2, and KMT2D) in 14 of 59 trios, greatly exceeding variation in control trios without CHD (p = 9.60e-06). In total, 32% of trios carried at least one putatively disease-associated variant across 19 loci,suggesting that inherited and de novo variation across a heterogeneous group of loci may contribute to disease risk.
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Affiliation(s)
- James R. Priest
- Division of Pediatric Cardiology, Stanford University School of Medicine, Stanford University, Stanford, California, United States of America
- Cardiovascular Institute, Stanford University School of Medicine, Stanford University, Stanford, California, United States of America
| | - Kazutoyo Osoegawa
- Department of Pathology, Stanford University School of Medicine, Stanford University, Stanford, California, United States of America
| | - Nebil Mohammed
- University of California San Francisco Benioff Children’s Hospital Oakland, University of California San Francisco, San Francisco, California, United States of America
| | - Vivek Nanda
- Department of Vascular Surgery, Stanford University School of Medicine, Stanford University, Stanford, California, United States of America
| | - Ramendra Kundu
- Division of Cardiovascular Medicine, Stanford University School of Medicine, Stanford University, Stanford, California, United States of America
| | - Kathleen Schultz
- University of California San Francisco Benioff Children’s Hospital Oakland, University of California San Francisco, San Francisco, California, United States of America
| | - Edward J. Lammer
- University of California San Francisco Benioff Children’s Hospital Oakland, University of California San Francisco, San Francisco, California, United States of America
| | - Santhosh Girirajan
- Departments of Biochemistry, Molecular Biology, and Anthropology, Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Todd Scheetz
- College of Engineering, University of Iowa, Iowa City, Iowa, United States of America
| | - Daryl Waggott
- Division of Cardiovascular Medicine, Stanford University School of Medicine, Stanford University, Stanford, California, United States of America
| | - Francois Haddad
- Cardiovascular Institute, Stanford University School of Medicine, Stanford University, Stanford, California, United States of America
- Division of Cardiovascular Medicine, Stanford University School of Medicine, Stanford University, Stanford, California, United States of America
| | - Sushma Reddy
- Division of Pediatric Cardiology, Stanford University School of Medicine, Stanford University, Stanford, California, United States of America
- Cardiovascular Institute, Stanford University School of Medicine, Stanford University, Stanford, California, United States of America
| | - Daniel Bernstein
- Division of Pediatric Cardiology, Stanford University School of Medicine, Stanford University, Stanford, California, United States of America
- Cardiovascular Institute, Stanford University School of Medicine, Stanford University, Stanford, California, United States of America
| | - Trudy Burns
- College of Public Health, University of Iowa, Iowa City, Iowa, United States of America
| | - Jeffrey D. Steimle
- Department of Pathology, University of Chicago, Chicago, Illinois, United States of America
| | - Xinan H. Yang
- Department of Pathology, University of Chicago, Chicago, Illinois, United States of America
| | - Ivan P. Moskowitz
- Department of Pathology, University of Chicago, Chicago, Illinois, United States of America
| | - Matthew Hurles
- Wellcome Trust Sanger Institute, Hinxton, Cambridge, United Kingdom
| | - Richard P. Lifton
- Department of Genetics, Yale University, New Haven, Connecticut, United States of America
- Howard Hughes Medical Institute, Chevy Chase, Maryland, United States of America
| | - Debbie Nickerson
- Department of Genome Sciences, University of Washington, Seattle, Washington, United States of America
| | - Michael Bamshad
- Department of Genome Sciences, University of Washington, Seattle, Washington, United States of America
- Department of Pediatrics, University of Washington, Seattle, Washington, United States of America
| | - Evan E. Eichler
- Howard Hughes Medical Institute, Chevy Chase, Maryland, United States of America
- Department of Genome Sciences, University of Washington, Seattle, Washington, United States of America
| | - Seema Mital
- Department of Pediatrics, University of Toronto, Toronto, Ontario, Canada
| | - Val Sheffield
- Howard Hughes Medical Institute, Chevy Chase, Maryland, United States of America
- Division of Medical Genetics, University of Iowa Carver College of Medicine, Iowa City, Iowa, United States of America
| | - Thomas Quertermous
- Cardiovascular Institute, Stanford University School of Medicine, Stanford University, Stanford, California, United States of America
- Division of Cardiovascular Medicine, Stanford University School of Medicine, Stanford University, Stanford, California, United States of America
| | - Bruce D. Gelb
- Mindich Child Health and Development Institute, Icahn School of Medicine at Mt. Sinai, New York, New York, United States of America
| | - Michael Portman
- Department of Pediatrics, University of Washington, Seattle, Washington, United States of America
| | - Euan A. Ashley
- Cardiovascular Institute, Stanford University School of Medicine, Stanford University, Stanford, California, United States of America
- Division of Cardiovascular Medicine, Stanford University School of Medicine, Stanford University, Stanford, California, United States of America
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19
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Watanabe H, Minamino T. Rare Variants in <i>ANK2</i> Associated With Various Inherited Arrhythmia Syndromes. Circ J 2016; 80:2423-2424. [DOI: 10.1253/circj.cj-16-1085] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Hiroshi Watanabe
- Department of Cardiovascular Biology and Medicine, Niigata University Graduate School of Medical and Dental Sciences
| | - Tohru Minamino
- Department of Cardiovascular Biology and Medicine, Niigata University Graduate School of Medical and Dental Sciences
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20
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Abstract
Ion channels in the myocardial cellular membrane are responsible for allowing the cardiac action potential. Genetic abnormalities in these channels can predispose to life-threatening arrhythmias. We discuss the basic science of the cardiac action potential; outline the different clinical entities, including information regarding overlapping diagnoses, touching upon relevant genetics, new innovations in screening, diagnosis, risk stratification, and management. The special considerations of sudden unexplained death and sudden infant death syndrome are discussed. Scientists and clinicians continue to reconcile the rapidly growing body of knowledge regarding the molecular mechanisms and genetics while continuing to improve our understanding of the various clinical entities and their diagnosis and management in clinical setting. Two separate searches were run on the National Center for Biotechnology Information's website. The first using the term cardiac channelopathies was run on the PubMed database using filters for time (published in past 5 years) and age (birth-18 years), yielding 47 results. The second search using the medical subject headings (MeSH) database with the search terms “Long QT Syndrome” (MeSH) and “Short QT Syndrome” (MeSH) and “Brugada Syndrome” (MeSH) and “Catecholaminergic Polymorphic Ventricular Tachycardia” (MeSH), applying the same filters yielded 467 results. The abstracts of these articles were studied, and the articles were categorized and organized. Articles of relevance were read in full. As and where applicable, relevant references and citations from the primary articles where further explored and read in full.
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Affiliation(s)
- Shashank P Behere
- Department of Pediatrics, Dartmouth Hitchcock Medical Center, Lebanon, New Hampshire, USA
| | - Steven N Weindling
- Department of Pediatric Cardiology, Dartmouth Hitchcock Medical Center, Lebanon, New Hampshire, USA
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21
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Millat G, Chanavat V, Rousson R. Evaluation of a new high-throughput next-generation sequencing method based on a custom AmpliSeq™ library and ion torrent PGM™ sequencing for the rapid detection of genetic variations in long QT syndrome. Mol Diagn Ther 2015; 18:533-9. [PMID: 24687331 DOI: 10.1007/s40291-014-0099-y] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
BACKGROUND AND OBJECTIVE Inherited long QT syndrome (LQTS) is a cardiac channelopathy associated with a high risk of sudden death. The prevalence has been estimated at close to 1:2,000. Due to large cohorts to investigate and high rate of private mutations, mutational screening must be performed using an extremely sensitive and specific detection method. Mutational screening is crucial as this may have implications for therapy and management of LQTS patients. METHODS Next-generation sequencing (NGS) workflow based on a custom AmpliSeq™ panel was designed for sequencing the five most prevalent cardiomyopathy-causing genes (KCNQ1, KCNH2, SCN5A, KCNE1, KCNE2) on Ion PGM™ Sequencer. A cohort of 30 previously studied patients was screened to evaluate this strategy in terms of sensitivity, specificity, practicability, and cost. In silico analysis was performed using NextGENe(®) software. RESULTS Our AmpliSeq™ custom panel allowed us to explore 86 % of targeted sequences efficiently. Using adjusted alignment settings, all genetic variants (40 substitutions, 17 indels) present in covered regions and previously detected by high-resolution melt (HRM)/sequencing were readily identified. Uncovered targeted regions, which were mainly located in KCNH2, were further analyzed by HRM/sequencing strategy. Complete molecular investigation was performed faster and cheaper than with previously used mutation detection methods. CONCLUSION Finally, these results suggested that our new NGS approach based on AmpliSeq™ libraries and Ion PGM™ sequencing is a highly efficient, fast, and cheap high-throughput mutation detection method that is ready to be deployed in clinical laboratories. This method will allow fast identification of LQTS mutations that will have further implications for therapeutics.
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Affiliation(s)
- Gilles Millat
- Laboratoire de Cardiogénétique Moléculaire, Centre de Biologie et Pathologie Est, Hospices Civils de Lyon, Lyon, 69677, Bron Cedex, France,
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22
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Congenital long QT syndrome: Severe Torsades de pointes provoked by epinephrine in a digenic mutation carrier. Heart Lung 2014; 43:541-5. [DOI: 10.1016/j.hrtlng.2014.07.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2014] [Revised: 07/22/2014] [Accepted: 07/24/2014] [Indexed: 02/02/2023]
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23
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Hertz CL, Ferrero-Miliani L, Frank-Hansen R, Morling N, Bundgaard H. A comparison of genetic findings in sudden cardiac death victims and cardiac patients: the importance of phenotypic classification. Europace 2014; 17:350-7. [PMID: 25345827 DOI: 10.1093/europace/euu210] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Sudden cardiac death (SCD) is responsible for a large proportion of non-traumatic, sudden and unexpected deaths in young individuals. Sudden cardiac death is a known manifestation of several inherited cardiac diseases. In post-mortem examinations, about two-thirds of the SCD cases show structural abnormalities at autopsy. The remaining cases stay unexplained after thorough investigations and are referred to as sudden unexplained deaths. A routine forensic investigation of the SCD victims in combination with genetic testing makes it possible to establish a likely diagnosis in some of the deaths previously characterized as unexplained. Additionally, a genetic diagnose in a SCD victim with a structural disease may not only add to the differential diagnosis, but also be of importance for pre-symptomatic family screening. In the case of SCD, the optimal establishment of the cause of death and management of the family call for standardized post-mortem procedures, genetic screening, and family screening. Studies of genetic testing in patients with primary arrhythmia disorders or cardiomyopathies and of victims of SCD presumed to be due to primary arrhythmia disorders or cardiomyopathies, were systematically identified and reviewed. The frequencies of disease-causing mutation were on average between 16 and 48% in the cardiac patient studies, compared with ∼10% in the post-mortem studies. The frequency of pathogenic mutations in heart genes in cardiac patients is up to four-fold higher than that in SCD victims in a forensic setting. Still, genetic investigation of SCD victims is important for the diagnosis and the possible investigation of relatives at risk.
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Affiliation(s)
- Christin L Hertz
- Section of Forensic Genetics, Department of Forensic Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, 11 Frederik V's Vej, 2100 Copenhagen, Denmark
| | - Laura Ferrero-Miliani
- Section of Forensic Genetics, Department of Forensic Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, 11 Frederik V's Vej, 2100 Copenhagen, Denmark
| | - Rune Frank-Hansen
- Section of Forensic Genetics, Department of Forensic Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, 11 Frederik V's Vej, 2100 Copenhagen, Denmark
| | - Niels Morling
- Section of Forensic Genetics, Department of Forensic Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, 11 Frederik V's Vej, 2100 Copenhagen, Denmark
| | - Henning Bundgaard
- Rigshospitalets Unit for Inherited Heart Diseases, The Heart Centre, Rigshospitalet, Copenhagen University Hospital, Denmark
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Partemi S, Vidal MC, Striano P, Campuzano O, Allegue C, Pezzella M, Elia M, Parisi P, Belcastro V, Casellato S, Giordano L, Mastrangelo M, Pietrafusa N, Striano S, Zara F, Bianchi A, Buti D, La Neve A, Tassinari CA, Oliva A, Brugada R. Genetic and forensic implications in epilepsy and cardiac arrhythmias: a case series. Int J Legal Med 2014; 129:495-504. [PMID: 25119684 DOI: 10.1007/s00414-014-1063-4] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2014] [Accepted: 08/05/2014] [Indexed: 12/27/2022]
Abstract
Epilepsy affects approximately 3% of the world's population, and sudden death is a significant cause of death in this population. Sudden unexpected death in epilepsy (SUDEP) accounts for up to 17% of all these cases, which increases the rate of sudden death by 24-fold as compared to the general population. The underlying mechanisms are still not elucidated, but recent studies suggest the possibility that a common genetic channelopathy might contribute to both epilepsy and cardiac disease to increase the incidence of death via a lethal cardiac arrhythmia. We performed genetic testing in a large cohort of individuals with epilepsy and cardiac conduction disorders in order to identify genetic mutations that could play a role in the mechanism of sudden death. Putative pathogenic disease-causing mutations in genes encoding cardiac ion channel were detected in 24% of unrelated individuals with epilepsy. Segregation analysis through genetic screening of the available family members and functional studies are crucial tasks to understand and to prove the possible pathogenicity of the variant, but in our cohort, only two families were available. Despite further research should be performed to clarify the mechanism of coexistence of both clinical conditions, genetic analysis, applied also in post-mortem setting, could be very useful to identify genetic factors that predispose epileptic patients to sudden death, helping to prevent sudden death in patients with epilepsy.
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Affiliation(s)
- Sara Partemi
- Institute of Legal Medicine, School of Medicine, Catholic University, Rome, Italy
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25
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Wilde AAM, Lieve KVV. Double trouble, stick to the basics should be the rule! Heart Rhythm 2014; 11:2105-6. [PMID: 25063691 DOI: 10.1016/j.hrthm.2014.07.026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/15/2014] [Indexed: 10/25/2022]
Affiliation(s)
- Arthur A M Wilde
- Department of Clinical and Experimental Cardiology, Academic Medical Center, Amsterdam, The Netherlands.; Princess Al-Jawhara Albrahim Centre of Excellence in Research of Hereditary Disorders, King Abdulaziz University, Jeddah, Saudi Arabia.
| | - Krystien V V Lieve
- Department of Clinical and Experimental Cardiology, Academic Medical Center, Amsterdam, The Netherlands
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26
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Priest JR, Ceresnak SR, Dewey FE, Malloy-Walton LE, Dunn K, Grove ME, Perez MV, Maeda K, Dubin AM, Ashley EA. Molecular diagnosis of long QT syndrome at 10 days of life by rapid whole genome sequencing. Heart Rhythm 2014; 11:1707-13. [PMID: 24973560 DOI: 10.1016/j.hrthm.2014.06.030] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/24/2014] [Indexed: 11/17/2022]
Abstract
BACKGROUND The advent of clinical next generation sequencing is rapidly changing the landscape of rare disease medicine. Molecular diagnosis of long QT syndrome (LQTS) can affect clinical management, including risk stratification and selection of pharmacotherapy on the basis of the type of ion channel affected, but results from the current gene panel testing requires 4-16 weeks before return to clinicians. OBJECTIVE A term female infant presented with 2:1 atrioventricular block and ventricular arrhythmias consistent with perinatal LQTS, requiring aggressive treatment including epicardial pacemaker and cardioverter-defibrillator implantation and sympathectomy on day of life 2. We sought to provide a rapid molecular diagnosis for the optimization of treatment strategies. METHODS We performed Clinical Laboratory Improvement Amendments-certified rapid whole genome sequencing (WGS) with a speed-optimized bioinformatics platform to achieve molecular diagnosis at 10 days of life. RESULTS We detected a known pathogenic variant in KCNH2 that was demonstrated to be paternally inherited by follow-up genotyping. The unbiased assessment of the entire catalog of human genes provided by WGS revealed a maternally inherited variant of unknown significance in a novel gene. CONCLUSION Rapid clinical WGS provides faster and more comprehensive diagnostic information at 10 days of life than does standard gene panel testing. In selected clinical scenarios such as perinatal LQTS, rapid WGS can provide more timely and clinically actionable information than can a standard commercial test.
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Affiliation(s)
- James R Priest
- Division of Pediatric Cardiology, Stanford University School of Medicine, Stanford University, Stanford, California; Child Health Research Institute; Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, California
| | - Scott R Ceresnak
- Division of Pediatric Cardiology, Stanford University School of Medicine, Stanford University, Stanford, California; Child Health Research Institute; Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, California
| | - Frederick E Dewey
- Division of Cardiovascular Medicine; Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, California
| | - Lindsey E Malloy-Walton
- Division of Pediatric Cardiology, Stanford University School of Medicine, Stanford University, Stanford, California; Child Health Research Institute; Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, California
| | - Kyla Dunn
- Children's Heart Center, Lucile Packard Children's Hospital at Stanford, Palo Alto, California; Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, California
| | - Megan E Grove
- Division of Cardiovascular Medicine; Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, California
| | - Marco V Perez
- Division of Cardiovascular Medicine; Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, California
| | - Katsuhide Maeda
- Division of Cardiothoracic Surgery; Child Health Research Institute; Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, California
| | - Anne M Dubin
- Division of Pediatric Cardiology, Stanford University School of Medicine, Stanford University, Stanford, California; Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, California
| | - Euan A Ashley
- Division of Cardiovascular Medicine; Child Health Research Institute; Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, California.
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27
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Chang RKR, Lan YT, Silka MJ, Morrow H, Kwong A, Smith-Lang J, Wallerstein R, Lin HJ. Genetic variants for long QT syndrome among infants and children from a statewide newborn hearing screening program cohort. J Pediatr 2014; 164:590-5.e1-3. [PMID: 24388587 PMCID: PMC3943925 DOI: 10.1016/j.jpeds.2013.11.011] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/17/2013] [Revised: 10/01/2013] [Accepted: 11/06/2013] [Indexed: 10/25/2022]
Abstract
OBJECTIVES Autosomal recessive long QT syndrome (LQTS), or Jervell and Lange-Nielsen syndrome (JLNS), can be associated with sensorineural hearing loss. We aimed to explore newborn hearing screening combined with electrocardiograms (ECGs) for early JLNS detection. STUDY DESIGN In California, we conducted statewide, prospective ECG screening of children ≤ 6 years of age with unilateral or bilateral, severe or profound, sensorineural or mixed hearing loss. Families were identified through newborn hearing screening and interviewed about medical and family histories. Twelve-lead ECGs were obtained. Those with positive histories or heart rate corrected QT (QTc) intervals ≥ 450 ms had repeat ECGs. DNA sequencing of 12 LQTS genes was performed for repeat QTc intervals ≥ 450 ms. RESULTS We screened 707 subjects by ECGs (number screened/number of responses = 91%; number of responses/number of families who were mailed invitations = 54%). Of these, 73 had repeat ECGs, and 19 underwent gene testing. No subject had homozygous or compound heterozygous LQTS mutations, as in JLNS. However, 3 individuals (with QTc intervals of 472, 457, and 456 ms, respectively) were heterozygous for variants that cause truncation or missplicing: 2 in KCNQ1 (c.1343dupC or p.Glu449Argfs*14; c.1590+1G>A or p.Glu530sp) and 1 in SCN5A (c.5872C>T or p.Arg1958*). CONCLUSIONS In contrast to reports of JLNS in up to 4% of children with sensorineural hearing loss, we found no examples of JLNS. Because the 3 variants identified were unrelated to hearing, they likely represent the prevalence of potential LQTS mutations in the general population. Further studies are needed to define consequences of such mutations and assess the overall prevalence.
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Affiliation(s)
- Ruey-Kang R. Chang
- Department of Pediatrics, Harbor-UCLA Medical Center and Los Angeles Biomedical Research Institute, Torrance, California
| | | | - Michael J. Silka
- Children’s Hospital Los Angeles – University of Southern California, Los Angeles, CA
| | - Hallie Morrow
- California Department of Health Care Services, Sacramento, CA
| | - Alan Kwong
- Department of Pediatrics, Harbor-UCLA Medical Center and Los Angeles Biomedical Research Institute, Torrance, California
| | | | | | - Henry J. Lin
- Department of Pediatrics, Harbor-UCLA Medical Center and Los Angeles Biomedical Research Institute, Torrance, California
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28
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Gong Q, Stump MR, Zhou Z. Position of premature termination codons determines susceptibility of hERG mutations to nonsense-mediated mRNA decay in long QT syndrome. Gene 2014; 539:190-7. [PMID: 24530480 DOI: 10.1016/j.gene.2014.02.012] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2013] [Revised: 02/01/2014] [Accepted: 02/10/2014] [Indexed: 01/26/2023]
Abstract
The degradation of human ether-a-go-go-related gene (hERG, KCNH2) transcripts containing premature termination codon (PTC) mutations by nonsense-mediated mRNA decay (NMD) is an important mechanism of long QT syndrome type 2 (LQT2). The mechanisms governing the recognition of PTC-containing hERG transcripts as NMD substrates have not been established. We used a minigene system to study two frameshift mutations, R1032Gfs 25 and D1037Rfs 82. R1032Gfs 25 introduces a PTC in exon 14, whereas D1037Rfs 82 causes a PTC in the last exon (exon 15). We showed that R1032Gfs 25, but not D1037Rfs 82, reduced the level of mutant mRNA compared to the wild-type minigene in an NMD-dependent manner. The deletion of intron 14 prevented degradation of R1032Gfs 25 mRNA indicating that a downstream intron is required for NMD. The recognition and elimination of PTC-containing transcripts by NMD required that the mutation be positioned >54-60 nt upstream of the 3'-most exon-exon junction. Finally, we used a full-length hERG splicing-competent construct to show that inhibition of downstream intron splicing by antisense morpholino oligonucleotides inhibited NMD and rescued the functional expression of a third LQT2 mutation, Y1078. The present study defines the positional requirements for the susceptibility of LQT2 mutations to NMD and posits that the majority of reported LQT2 nonsense and frameshift mutations are potential targets of NMD.
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Affiliation(s)
- Qiuming Gong
- Knight Cardiovascular Institute, Oregon Health & Science University, Portland, OR, USA
| | - Matthew R Stump
- Knight Cardiovascular Institute, Oregon Health & Science University, Portland, OR, USA
| | - Zhengfeng Zhou
- Knight Cardiovascular Institute, Oregon Health & Science University, Portland, OR, USA.
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Hofman N, Tan HL, Alders M, Kolder I, de Haij S, Mannens MMAM, Lombardi MP, Dit Deprez RHL, van Langen I, Wilde AAM. Yield of molecular and clinical testing for arrhythmia syndromes: report of 15 years' experience. Circulation 2013; 128:1513-21. [PMID: 23963746 DOI: 10.1161/circulationaha.112.000091] [Citation(s) in RCA: 111] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
BACKGROUND Sudden cardiac death is often caused by inherited arrhythmia syndromes, particularly if it occurs at a young age. In 1996, we started a cardiogenetics clinic aimed at diagnosing such syndromes and providing timely (often presymptomatic) treatment to families in which such syndromes or sudden cardiac death existed. We studied the yield of DNA testing for these syndromes using a candidate-gene approach over our 15 years of experience. METHODS AND RESULTS We analyzed the yield of DNA testing. In subanalyses, we studied differences in the yield of DNA testing over time, between probands with isolated or familial cases and between probands with or without clear disease-specific clinical characteristics. In cases of sudden unexplained death (antemortem or postmortem analysis of the deceased not performed or providing no diagnosis), we analyzed the yield of cardiological investigations. Among 7021 individuals who were counseled, 6944 from 2298 different families (aged 41 ± 19 years; 49% male) were analyzed. In 702 families (31%), a possible disease-causing mutation was detected. Most mutations were found in families with long-QT syndrome (47%) or hypertrophic cardiomyopathy (46%). Cascade screening revealed 1539 mutation-positive subjects. The mutation detection rate decreased over time, in part because probands with a less severe phenotype were studied, and was significantly higher in familial than in isolated cases. We counseled 372 families after sudden unexplained death; in 29% of them (n=108), an inherited arrhythmia syndrome was diagnosed. CONCLUSIONS The proportion of disease-causing mutations found decreased over time, in part because probands with a less severe phenotype were studied. Systematic screening of families identified many (often presymptomatic) mutation-positive subjects.
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Affiliation(s)
- Nynke Hofman
- Department of Clinical Genetics (N.H., M.A., S.d.H., M.M.A.M.M., M.P.L., R.H.L.d.D., I.v.L.), Department of Cardiology (H.L.T., A.A.M.W.), and Department of Epidemiology, Biostatistics, and Bioinformatics (I.K.), Academic Medical Center, Amsterdam, The Netherlands
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30
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Perez MV, Ashley EA. Taming Rare Variation With Known Biology in Long QT Syndrome. ACTA ACUST UNITED AC 2013; 6:227-9. [DOI: 10.1161/circgenetics.113.000199] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Marco V. Perez
- From the Center for Inherited Cardiovascular Disease, Division of Cardiovascular Medicine, Stanford University, Stanford, CA
| | - Euan A. Ashley
- From the Center for Inherited Cardiovascular Disease, Division of Cardiovascular Medicine, Stanford University, Stanford, CA
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