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KCNQ1 gain-of-function mutation in familial atrial fibrillation.

Yi-Han Chen, Shi-Jie Xu, Saïd Bendahhou, Xiao-Liang Wang, Ying Wang, Wen-Yuan Xu, Hong-Wei Jin, Hao Sun, Xiao-Yan Su, Qi-Nan Zhuang, Yi-Qing Yang, Yue-Bin Li, Yi Liu, Hong-Ju Xu, Xiao-Fei Li, Ning Ma, Chun-Ping Mou, Zhu Chen, Jacques Barhanin, Wei Huang

Science, 2003 Jan 10 , 299, 251-4

Atrial fibrillation (AF) is a common cardiac arrhythmia whose molecular etiology is poorly understood. We studied a family with hereditary persistent AF and identified the causative mutation (S140G) in the KCNQ1 (KvLQT1) gene on chromosome 11p15.5. The KCNQ1 gene encodes the pore-forming alpha subunit of the cardiac I(Ks) channel (KCNQ1/KCNE1), the KCNQ1/KCNE2 and the KCNQ1/KCNE3 potassium channels. Functional analysis of the S140G mutant revealed a gain-of-function effect on the KCNQ1/KCNE1 and the KCNQ1/KCNE2 currents, which contrasts with the dominant negative or loss-of-function effects of the KCNQ1 mutations previously identified in patients with long QT syndrome. Thus, the S140G mutation is likely to initiate and maintain AF by reducing action potential duration and effective refractory period in atrial myocytes.