Mutations in sodium channel beta1- and beta2-subunits associated with atrial fibrillation. Watanabe, H., Darbar, D., Kaiser, D., Jiramongkolchai, K., Chopra, S., Donahue, B., Kannankeril, P., & Roden, D. Circ Arrhythm Electrophysiol, 2(3):268–275, Jun, 2009.
bibtex   
@Article{RSM:Wat2009,
  author =       "H. Watanabe and D. Darbar and D.W. Kaiser and K.
                 Jiramongkolchai and S. Chopra and B.S. Donahue and P.J.
                 Kannankeril and D.M. Roden",
  title =        "Mutations in sodium channel beta1- and beta2-subunits
                 associated with atrial fibrillation.",
  journal =      "Circ Arrhythm Electrophysiol",
  year =         "2009",
  month =        "Jun",
  volume =       "2",
  number =       "3",
  pages =        "268--275",
  robnote =      "BACKGROUND: We and others have reported mutations in the
                 cardiac predominant sodium channel gene SCN5A in patients
                 with atrial fibrillation (AF). We also have reported that
                 SCN1B is associated with Brugada syndrome and isolated
                 cardiac conduction disease. We tested the hypothesis that
                 mutations in the 4 sodium channel beta-subunit genes
                 SCN1B-SCN4B contribute to AF susceptibility. METHODS AND
                 RESULTS: Screening for mutations in the 4 beta-subunit
                 genes was performed in 480 patients with AF (118 patients
                 with lone AF and 362 patients with AF and cardiovascular
                 disease) and 548 control subjects (188 ethnically defined
                 anonymized subjects and 360 subjects without AF). The
                 effects of mutant beta-subunits on SCN5A mediated currents
                 were studied using electrophysiological studies. We
                 identified 2 nonsynonymous variants in SCN1B (resulting in
                 R85H, D153N) and 2 in SCN2B (R28Q, R28W) in patients with
                 AF. These occur at residues highly conserved across
                 mammals and were absent in control subjects. In 3 of 4
                 mutation carriers, the ECGs showed saddleback-type
                 ST-segment elevation in the right precordial leads.
                 Transcripts encoding both SCN1B and SCN2B were detected in
                 human atrium and ventricle. In heterologous expression
                 studies using Chinese hamster ovary cells, the mutant
                 beta1- or beta2-subunits reduced SCN5A-mediated current
                 and altered channel gating compared with coexpression of
                 wild-type subunits. CONCLUSIONS: Loss of function
                 mutations in sodium channel beta-subunits were identified
                 in patients with AF and were associated with a distinctive
                 ECG phenotype. These findings further support the
                 hypothesis that decreased sodium current enhances AF
                 susceptibility.",
  bibdate =      "Mon Dec 7 22:15:47 2009",
  pmcid =        "2010/06/01 PHST- 2009/03/06 [aheadofprint]",
}

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