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Articles by B. S Donahue
Total Records ( 2 ) for B. S Donahue
  H Watanabe , D Darbar , D. W Kaiser , K Jiramongkolchai , S Chopra , B. S Donahue , P. J Kannankeril and D. M. Roden
 

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 β-subunit genes SCN1BSCN4B contribute to AF susceptibility.

Methods and Results— Screening for mutations in the 4 β-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 β-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 β1- or β2-subunits reduced SCN5A-mediated current and altered channel gating compared with coexpression of wild-type subunits.

Conclusions— Loss of function mutations in sodium channel β-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.

  S. C Body , C. D Collard , S. K Shernan , A. A Fox , K. Y Liu , M. D Ritchie , T. E Perry , J. D Muehlschlegel , S Aranki , B. S Donahue , M Pretorius , J. C Estrada , P. T Ellinor , C Newton Cheh , C. E Seidman , J.G Seidman , D. S Herman; , P Lichtner , T Meitinger , A Pfeufer , S Kaab , N. J Brown , D. M Roden and D. Darbar
 

Background— Atrial fibrillation (AF) is the most common adverse event following coronary artery bypass graft surgery. A recent study identified chromosome 4q25 variants associated with AF in ambulatory populations. However, their role in postoperative AF is unknown. We hypothesized that genetic variants in the 4q25 chromosomal region are independently associated with postoperative AF after coronary artery bypass graft surgery.

Methods and Results— Two prospectively collected cohorts of patients undergoing coronary artery bypass graft surgery, with or without concurrent valve surgery, at 3 US centers. From a discovery cohort of 959 patients, clinical and genomic multivariate predictors of postoperative AF were identified by genotyping 45 single-nucleotide polymorphisms (SNPs) encompassing the 4q25 locus. Three SNPs were then assessed in a separately collected validation cohort of 494 patients. After adjustment for clinical predictors of postoperative AF and multiple comparisons, rs2200733, rs13143308, and 5 other linked SNPs independently predicted postoperative AF in the discovery cohort. Additive odds ratios for the 7 associated 4q25 SNPs ranged between 1.57 and 2.17 (P=8.0x10–4 to 3.4x10–6). Association with postoperative AF were measured and replicated for rs2200733 and rs13143308 in the validation cohort.

Conclusions— In 2 independently collected cardiac surgery cohorts, noncoding SNPs within the chromosome 4q25 region are independently associated with postoperative AF after coronary artery bypass graft surgery after adjusting for clinical covariates and multiple comparisons.

 
 
 
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