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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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2
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González-Garrido A, Domínguez-Pérez M, Jacobo-Albavera L, López-Ramírez O, Guevara-Chávez JG, Zepeda-García O, Iturralde P, Carnevale A, Villarreal-Molina T. Compound Heterozygous KCNQ1 Mutations Causing Recessive Romano-Ward Syndrome: Functional Characterization by Mutant Co-expression. Front Cardiovasc Med 2021; 8:625449. [PMID: 33693037 PMCID: PMC7937651 DOI: 10.3389/fcvm.2021.625449] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Accepted: 01/11/2021] [Indexed: 11/13/2022] Open
Abstract
Next Generation Sequencing has identified many KCNQ1 genetic variants associated with type 1 long QT or Romano-Ward syndrome, most frequently inherited in an autosomal dominant fashion, although recessive forms have been reported. Particularly in the case of missense variants, functional studies of mutants are of aid to establish variant pathogenicity and to understand the mechanistic basis of disease. Two compound heterozygous KCNQ1 mutations (p.A300T and p.P535T) were previously found in a child who suffered sudden death. To provide further insight into the clinical significance and basis for pathogenicity of these variants, different combinations of wildtype, A300T and P535T alleles were co-expressed with the accessory β-subunit minK in HEK293 cells, to analyze colocalization with the plasma membrane and some biophysical phenotypes of homo and heterotetrameric channels using the patch-clamp technique. A300T homotetrameric channels showed left-shifted activation V1/2 as previously observed in Xenopus oocytes, decreased maximum conductance density, slow rise-time300ms, and a characteristic use-dependent response. A300T slow rise-time300ms and use-dependent response behaved as dominant biophysical traits for all allele combinations. The P535T variant significantly decreased maximum conductance density and Kv7.1-minK-plasma membrane colocalization. P535T/A300T heterotetrameric channels showed decreased colocalization with plasma membrane, slow rise-time300ms and the A300T characteristic use-dependent response. While A300T left shifted activation voltage dependence behaved as a recessive trait when co-expressed with WT alleles, it was dominant when co-expressed with P535T alleles. Conclusions: The combination of P535T/A300T channel biophysical properties is compatible with recessive Romano Ward syndrome. Further analysis of other biophysical traits may identify other mechanisms involved in the pathophysiology of this disease.
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Affiliation(s)
- Antonia González-Garrido
- Laboratorio de Genómica de Enfermedades Cardiovasculares, Instituto Nacional de Medicina Genómica, Mexico City, Mexico.,Cátedras CONACyT, Consejo Nacional de Ciencia y Tecnología, Mexico City, Mexico
| | - Mayra Domínguez-Pérez
- Laboratorio de Genómica de Enfermedades Cardiovasculares, Instituto Nacional de Medicina Genómica, Mexico City, Mexico
| | - Leonor Jacobo-Albavera
- Laboratorio de Genómica de Enfermedades Cardiovasculares, Instituto Nacional de Medicina Genómica, Mexico City, Mexico
| | - Omar López-Ramírez
- Department of Neurobiology, University of Chicago, Chicago, IL, United States
| | - José Guadalupe Guevara-Chávez
- Laboratorio de Genómica de Enfermedades Cardiovasculares, Instituto Nacional de Medicina Genómica, Mexico City, Mexico
| | - Oscar Zepeda-García
- Laboratorio de Genómica de Enfermedades Cardiovasculares, Instituto Nacional de Medicina Genómica, Mexico City, Mexico
| | - Pedro Iturralde
- Departamento de Electrofisiología, Instituto Nacional de Cardiología "Ignacio Chávez", Mexico, Mexico
| | - Alessandra Carnevale
- Laboratorio de Enfermedades Mendelianas, Instituto Nacional de Medicina Genómica, Mexico, Mexico
| | - Teresa Villarreal-Molina
- Laboratorio de Genómica de Enfermedades Cardiovasculares, Instituto Nacional de Medicina Genómica, Mexico City, Mexico
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Synková I, Bébarová M, Andršová I, Chmelikova L, Švecová O, Hošek J, Pásek M, Vít P, Valášková I, Gaillyová R, Navrátil R, Novotný T. Long-QT founder variant T309I-Kv7.1 with dominant negative pattern may predispose delayed afterdepolarizations under β-adrenergic stimulation. Sci Rep 2021; 11:3573. [PMID: 33574382 PMCID: PMC7878757 DOI: 10.1038/s41598-021-81670-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Accepted: 12/30/2020] [Indexed: 11/30/2022] Open
Abstract
The variant c.926C > T (p.T309I) in KCNQ1 gene was identified in 10 putatively unrelated Czech families with long QT syndrome (LQTS). Mutation carriers (24 heterozygous individuals) were more symptomatic compared to their non-affected relatives (17 individuals). The carriers showed a mild LQTS phenotype including a longer QTc interval at rest (466 ± 24 ms vs. 418 ± 20 ms) and after exercise (508 ± 32 ms vs. 417 ± 24 ms), 4 syncopes and 2 aborted cardiac arrests. The same haplotype associated with the c.926C > T variant was identified in all probands. Using the whole cell patch clamp technique and confocal microscopy, a complete loss of channel function was revealed in the homozygous setting, caused by an impaired channel trafficking. Dominant negativity with preserved reactivity to β-adrenergic stimulation was apparent in the heterozygous setting. In simulations on a human ventricular cell model, the dysfunction resulted in delayed afterdepolarizations (DADs) and premature action potentials under β-adrenergic stimulation that could be prevented by a slight inhibition of calcium current. We conclude that the KCNQ1 variant c.926C > T is the first identified LQTS-related founder mutation in Central Europe. The dominant negative channel dysfunction may lead to DADs under β-adrenergic stimulation. Inhibition of calcium current could be possible therapeutic strategy in LQTS1 patients refractory to β-blocker therapy.
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Affiliation(s)
- Iva Synková
- Department of Medical Genetics, University Hospital Brno and Faculty of Medicine, Masaryk University, Jihlavská 20, 625 00, Brno, Czech Republic.,Department of Experimental Biology, Faculty of Science, Masaryk University, Kotlářská 267/2, 611 37, Brno, Czech Republic
| | - Markéta Bébarová
- Department of Physiology, Faculty of Medicine, Masaryk University, Kamenice 5, 625 00, Brno, Czech Republic.
| | - Irena Andršová
- Department of Internal Medicine and Cardiology, University Hospital Brno and Faculty of Medicine, Masaryk University, Jihlavská 20, 625 00, Brno, Czech Republic
| | - Larisa Chmelikova
- Department of Biomedical Engineering, Faculty of Electrical Engineering and Communication, Brno University of Technology, Technická 10, 616 00, Brno, Czech Republic
| | - Olga Švecová
- Department of Physiology, Faculty of Medicine, Masaryk University, Kamenice 5, 625 00, Brno, Czech Republic
| | - Jan Hošek
- Division of Biologically Active Complexes and Molecular Magnets, Regional Centre of Advanced Technologies and Materials, Faculty of Science, Palacký University in Olomouc, Šlechtitelů 27, 783 71, Olomouc, Czech Republic
| | - Michal Pásek
- Department of Physiology, Faculty of Medicine, Masaryk University, Kamenice 5, 625 00, Brno, Czech Republic.,Institute of Thermomechanics, Czech Academy of Sciences, Dolejškova 5, 182 00, Prague, Czech Republic
| | - Pavel Vít
- Department of Paediatrics, University Hospital Brno and Faculty of Medicine, Masaryk University, Černopolní 9, 613 00, Brno, Czech Republic
| | - Iveta Valášková
- Department of Medical Genetics, University Hospital Brno and Faculty of Medicine, Masaryk University, Jihlavská 20, 625 00, Brno, Czech Republic
| | - Renata Gaillyová
- Department of Medical Genetics, University Hospital Brno and Faculty of Medicine, Masaryk University, Jihlavská 20, 625 00, Brno, Czech Republic
| | - Rostislav Navrátil
- Repromeda, Clinic for Reproductive Medicine and Preimplantation Genetic Diagnosis, Biology Park, Studentská 812/6, 625 00, Brno, Czech Republic
| | - Tomáš Novotný
- Department of Internal Medicine and Cardiology, University Hospital Brno and Faculty of Medicine, Masaryk University, Jihlavská 20, 625 00, Brno, Czech Republic
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Amirian A, Zafari Z, Dalili M, Saber S, Karimipoor M, Dabbagh Bagheri S, Fazelifar AF, Zeinali S. Detection of a new KCNQ1 frameshift mutation associated with Jervell and Lange-Nielsen syndrome in 2 Iranian families. J Arrhythm 2018; 34:286-290. [PMID: 29951145 PMCID: PMC6010008 DOI: 10.1002/joa3.12042] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Accepted: 01/20/2018] [Indexed: 12/22/2022] Open
Abstract
Jervell-Lange Nielsen syndrome (JLNS) with autosomal recessive inheritance is a congenital cardiovascular disorder characterized by prolongation of QT interval on the ECG and deafness. We have performed molecular investigation by haplotype analysis and DNA Sanger sequencing in 2 unrelated Iranian families with a history of syncope. Mutational screening of KCNQ1 gene revealed the novel homozygous frameshift mutation c.733-734delGG (p.G245Rfs*39) in 2 obviously unrelated cases of JLNS which is probably a founder mutation in Iran. The novel mutation detected in this study is the first time reported among Iranian population and will be beneficial in the tribe and region-specific cascade screening of LQTS in Iran.
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Affiliation(s)
- Azam Amirian
- Biotechnology Research CenterPasteur Institute of IranTehranIran
| | - Zahra Zafari
- Department of Medical GeneticsFaculty of Medical SciencesTarbiat Modares UniversityTehranIran
| | - Mohammad Dalili
- Cardiac Electrophysiology Research CenterRajaie Cardiovascular Medical, and Research CenterIran University of Medical SciencesTehranIran
| | - Siamak Saber
- Cardiac Electrophysiology Research CenterRajaie Cardiovascular Medical, and Research CenterIran University of Medical SciencesTehranIran
| | | | | | - Amir Farjam Fazelifar
- Cardiac Electrophysiology Research CenterRajaie Cardiovascular Medical, and Research CenterIran University of Medical SciencesTehranIran
| | - Sirous Zeinali
- Biotechnology Research CenterPasteur Institute of IranTehranIran
- Medical Genetics LaboratoryKawsar Human Genetics Research CenterTehranIran
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