Mutations in the genes KCND2 and KCND3 encoding the ion channels Kv4.2 and Kv4.3, conducting the cardiac fast transient outward current (ITO,f), are not a frequent cause of long QT syndrome

2005 ◽  
Vol 351 (1-2) ◽  
pp. 95-100 ◽  
Author(s):  
Rune Frank-Hansen ◽  
Lars Allan Larsen ◽  
Paal Andersen ◽  
Cathrine Jespersgaard ◽  
Michael Christiansen
Keyword(s):  
Ion Channels ◽  
Long Qt Syndrome ◽  
Outward Current ◽  
Transient Outward Current ◽  
Long Qt ◽  
Qt Syndrome ◽  
Fast Transient

Genotype and Severity of Long QT Syndrome

2001 ◽  
Vol 125 (1) ◽  
pp. 116-121
Author(s):  
Jeffrey A. Towbin ◽  
Zhiqing Wang ◽  
Hua Li
Keyword(s):  
Ion Channels ◽  
Sudden Death ◽  
Long Qt Syndrome ◽  
World Literature ◽  
State Of The Art ◽  
Clinical Severity ◽  
Clinical Aspects ◽  
Long Qt ◽  
Severity Of Disease ◽  
Qt Syndrome

Abstract Objectives.—To describe the state of the art of our understanding of the long QT syndromes and to provide the genetic correlation of clinical severity of patients with this disorder. Date Sources.—In this review, we outline data that were obtained from work in our laboratory, as well as information reported in the literature. Study Selection.—The information in this review spans the last decade; data were obtained from the studies that had the most impact, as well as from recent work at our laboratory. Data Extraction.—The data reported herein were extracted from the world literature on sudden death and the clinical aspects of long QT syndrome. The genes identified to date, mutations in these genes, and the biophysical perturbations in the mutated ion channels, as well as the severity of disease, are detailed. Data Synthesis.—The extracted data are described as a state-of-the-art review. Conclusions.—The long QT syndromes, genetically heterogeneous disorders due to mutations in genes encoding ion channels, are relatively common causes of syncope and sudden death. The affected genes, along with the genetic background of individuals, determine the clinical severity of disease. An understanding of the mechanisms responsible for long QT syndrome is expected to enable development of specific therapies.

scholarly journals hERG1a N-terminal eag domain–containing polypeptides regulate homomeric hERG1b and heteromeric hERG1a/hERG1b channels: A possible mechanism for long QT syndrome

2011 ◽  
Vol 138 (6) ◽  
pp. 581-592 ◽  
Author(s):  
Matthew C. Trudeau ◽  
Lisa M. Leung ◽  
Elon Roti Roti ◽  
Gail A. Robertson
Keyword(s):  
Amino Acids ◽  
Long Qt Syndrome ◽  
Outward Current ◽  
Inhibitory Effect ◽  
Pas Domain ◽  
Long Qt ◽  
Current Voltage ◽  
Qt Syndrome ◽  
Herg Channels

Human ether-á-go-go–related gene (hERG) potassium channels are critical for cardiac action potential repolarization. Cardiac hERG channels comprise two primary isoforms: hERG1a, which has a regulatory N-terminal Per-Arnt-Sim (PAS) domain, and hERG1b, which does not. Isolated, PAS-containing hERG1a N-terminal regions (NTRs) directly regulate NTR-deleted hERG1a channels; however, it is unclear whether hERG1b isoforms contain sufficient machinery to support regulation by hERG1a NTRs. To test this, we constructed a series of PAS domain–containing hERG1a NTRs (encoding amino acids 1–181, 1–228, 1–319, and 1–365). The NTRs were also predicted to form from truncation mutations that were linked to type 2 long QT syndrome (LQTS), a cardiac arrhythmia disorder associated with mutations in the hERG gene. All of the hERG1a NTRs markedly regulated heteromeric hERG1a/hERG1b channels and homomeric hERG1b channels by decreasing the magnitude of the current–voltage relationship and slowing the kinetics of channel closing (deactivation). In contrast, NTRs did not measurably regulate hERG1a channels. A short NTR (encoding amino acids 1–135) composed primarily of the PAS domain was sufficient to regulate hERG1b. These results suggest that isolated hERG1a NTRs directly interact with hERG1b subunits. Our results demonstrate that deactivation is faster in hERG1a/hERG1b channels compared to hERG1a channels because of fewer PAS domains, not because of an inhibitory effect of the unique hERG1b NTR. A decrease in outward current density of hERG1a/hERG1b channels by hERG1a NTRs may be a mechanism for LQTS.

scholarly journals Ion channels, long QT syndrome and arrhythmogenesis in ageing

2017 ◽  
Vol 44 ◽  
pp. 38-45 ◽  
Author(s):  
Kamalan Jeevaratnam ◽  
Karan R Chadda ◽  
Samantha C Salvage ◽  
Haseeb Valli ◽  
Shiraz Ahmad ◽  
...  
Keyword(s):  
Ion Channels ◽  
Long Qt Syndrome ◽  
Long Qt ◽  
Qt Syndrome

The Hereditary Long QT Syndrome

2010 ◽  
Vol 43 (2) ◽  
pp. 19
Author(s):  
PETER HULICK
Keyword(s):  
Long Qt Syndrome ◽  
Long Qt ◽  
Qt Syndrome
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