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(Circulation Research. 2005;96:703.)
© 2005 American Heart Association, Inc.

Editorials

Short QT Syndrome or Andersen Syndrome

Yin and Yang of Kir2.1 Channel Dysfunction

Eric Schulze-Bahr

From the From the Department of Cardiology and Angiology, Hospital of the University of Münster, and the Leibniz Institute for Arteriosclerosis Research at the University of Münster, Molecular Cardiology, Germany.

Correspondence to Eric Schulze-Bahr, MD, Molekular-Kardiologie Leibniz-Institut für Arterioskleroseforschung an der Universität Münster Domagkstr. 3 D-48149 Münster Germany. E-mail heart@uni-muenster.de

See related article, pages 800–807

Key Words: KCNJ2 • short QT syndrome • Andersen syndrome • gene • mutation • ventricular fibrillation

An extract of the first 250 words of the full text is provided, because this article has no abstract.

In 1994, the complete human cDNA of an inwardly rectifying K+ channel gene, KCNJ2 or Kir2.1, was isolated. Kir2.1 channels are important regulators of resting membrane potential of the cardiac (and also skeletal) muscle and cellular excitability,¹ since they cause an outflow of K+ in the hyperpolarized membrane state during the terminal phase of cardiac action potential repolarization. The cDNA encodes a small protein of 427 amino acids with 2 putative transmembrane domains (M1, M2) and a pore region (H5) and regulates the inward rectifier K+ current I_K1. Northern blot analysis demonstrated a 5.5-kb transcript with high levels in the heart, brain, placenta, lung, and skeletal muscle and lower levels in the kidney; in the heart, Kir2.1 channels are abundant in the atria, ventricle (with a high I_K1 conductance) and Purkinje fibers, but less frequent in nodal cells. On current knowledge, 4 subunits form a functional (ie, tetrameric) channel, but they also may co-assemble with other subunits of the Kir2.x family as heteromultimers² which indicates functional complexity and diversity.

In 2001, Plaster et al performed a genome-wide linkage analysis to identify the disease locus for Andersen (also Andersen–Tawil) syndrome.³ This rare syndrome can be found as a sporadic or autosomal dominant genetic trait and is characterized by a skeletal muscle phenotype (potassium-sensitive periodic paralysis caused by abnormal muscle relaxation, and histologically tubular aggregates), a cardiac phenotype (borderline or mildly prolonged QT interval, adrenergically mediated multifocal ventricular ectopy or tachycardia) and a distinct developmental dysmorphology that may include short stature, . . . [Full Text of this Article]

Related Article:

A Novel Form of Short QT Syndrome (SQT3) Is Caused by a Mutation in the KCNJ2 Gene

Silvia G. Priori, Sandeep V. Pandit, Ilaria Rivolta, Omer Berenfeld, Elena Ronchetti, Amit Dhamoon, Carlo Napolitano, Justus Anumonwo, Marina Raffaele di Barletta, Smitha Gudapakkam, Giuliano Bosi, Marco Stramba-Badiale, and José Jalife
Circ. Res. 2005 96: 800-807. [Abstract] [Full Text] [PDF]

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