title: Iron Overload Leading to Torsades de Pointes in β-Thalassemia and Long QT Syndrome.
abstract: The authors present a unique case of torsades de pointes in a β-thalassemia patient with early iron overload in the absence of any structural abnormalities as seen in hemochromatosis. Genetic testing showed a novel KCNQ1 gene mutation 1591C>T [Gln531Ter(X)]. Testing of the gene mutation in Xenopus laevis oocytes showed loss of function of the IKs current. The authors hypothesize that iron overload combined with the KCNQ1 gene mutation leads to prolongation of QTc and torsades de pointes.
authors.affiliation: Cardiology Division, Department of Internal Medicine, American University of Beirut Medical Center, Beirut, Lebanon; Department of Biochemistry and Molecular Genetics, American University of Beirut Medical Center, Beirut, Lebanon; Cardiac Electrophysiology, Cardiology, Department of Internal Medicine, American University of Beirut Faculty of Medicine and Medical Center, 3 Dag Hammarskjold Plaza, 8th Floor, New York, NY 10017, USA; Department of Biochemistry and Molecular Genetics, American University of Beirut Faculty of Medicine and Medical Center, 3 Dag Hammarskjold Plaza, 8th Floor, New York, NY 10017, USA.
authors.forename: Marwan M
authors.initials: MM
authors.lastname: Refaat
authors.affiliation: Division of Cardiology, Department of Medicine, University of California San Francisco Medical Center, 500 Parnassus Avenue, MUE-431, San Francisco, CA 94143-1354, USA.
authors.forename: Lea
authors.initials: L
authors.lastname: El Hage
authors.affiliation: Department of Biomedical Sciences, Faculty of Health and Medical Sciences, Danish National Research Foundation Centre for Cardiac Arrhythmia, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Annette Buur
authors.initials: AB
authors.lastname: Steffensen
authors.affiliation: Cardiology Division, Department of Internal Medicine, American University of Beirut Medical Center, Beirut, Lebanon.
authors.forename: Mostafa
authors.initials: M
authors.lastname: Hotait
authors.affiliation: Department of Biomedical Sciences, Faculty of Health and Medical Sciences, Danish National Research Foundation Centre for Cardiac Arrhythmia, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Nicole
authors.initials: N
authors.lastname: Schmitt
authors.affiliation: Division of Cardiology, Department of Medicine, University of California San Francisco Medical Center, 500 Parnassus Avenue, MUE-431, San Francisco, CA 94143-1354, USA.
authors.forename: Melvin
authors.initials: M
authors.lastname: Scheinman
authors.affiliation: Division of Cardiology, Department of Medicine, University of California San Francisco Medical Center, 500 Parnassus Avenue, MUE-431, San Francisco, CA 94143-1354, USA. Electronic address: badhwar@medicine.ucsf.edu.
authors.forename: Nitish
authors.initials: N
authors.lastname: Badhwar
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D019190:Iron Overload; D051657:KCNQ1 Potassium Channel / Q000235:genetics; D008133:Long QT Syndrome / Q000150:complications*; D009154:Mutation / Q000235:genetics; D016171:Torsades de Pointes; D055815:Young Adult; D017086:beta-Thalassemia / Q000150:complications*
chemical_list: D051657:KCNQ1 Potassium Channel; C496909:KCNQ1 protein, human
keywords: Iron overload; Long QT; β-thalassemia