title: Characterization of genome-wide association-identified variants for atrial fibrillation in African Americans.
abstract: BACKGROUND
  Despite a greater burden of risk factors, atrial fibrillation (AF) is less common among African Americans than European-descent populations. Genome-wide association studies (GWAS) for AF in European-descent populations have identified three predominant genomic regions associated with increased risk (1q21, 4q25, and 16q22). The contribution of these loci to AF risk in African American is unknown.
  
  
  RESULTS
  We studied 73 African Americans with AF from the Vanderbilt-Meharry AF registry and 71 African American controls, with no history of AF including after cardiac surgery. Tests of association were performed for 148 SNPs across the three regions associated with AF, and 22 SNPs were significantly associated with AF (P<0.05). The SNPs with the strongest associations in African Americans were both different from the index SNPs identified in European-descent populations and independent from the index European-descent population SNPs (r(2)<0.40 in HapMap CEU): 1q21 rs4845396 (odds ratio [OR] 0.30, 95% confidence interval [CI] 0.13-0.67, P = 0.003), 4q25 rs4631108 (OR 3.43, 95% CI 1.59-7.42, P = 0.002), and 16q22 rs16971547 (OR 8.1, 95% CI 1.46-45.4, P = 0.016). Estimates of European ancestry were similar among cases (23.6%) and controls (23.8%). Accordingly, the probability of having two copies of the European derived chromosomes at each region did not differ between cases and controls.
  
  
  CONCLUSIONS
  Variable European admixture at known AF loci does not explain decreased AF susceptibility in African Americans. These data support the role of 1q21, 4q25, and 16q22 variants in AF risk for African Americans, although the index SNPs differ from those identified in European-descent populations.
authors.affiliation: Department of Medicine, Vanderbilt University, Nashville, Tennessee, United States of America.
authors.forename: Jessica T
authors.initials: JT
authors.lastname: Delaney
authors.forename: Janina M
authors.initials: JM
authors.lastname: Jeff
authors.forename: Nancy J
authors.initials: NJ
authors.lastname: Brown
authors.forename: Mias
authors.initials: M
authors.lastname: Pretorius
authors.forename: Henry E
authors.initials: HE
authors.lastname: Okafor
authors.forename: Dawood
authors.initials: D
authors.lastname: Darbar
authors.forename: Dan M
authors.initials: DM
authors.lastname: Roden
authors.forename: Dana C
authors.initials: DC
authors.lastname: Crawford
mesh_terms: D001741:Black or African American / Q000235:genetics*; D001281:Atrial Fibrillation / Q000208:ethnology / Q000235:genetics*; D044383:Black People / Q000235:genetics; D016022:Case-Control Studies; D005260:Female; D020022:Genetic Predisposition to Disease; D014644:Genetic Variation; D055106:Genome-Wide Association Study; D005838:Genotype; D060148:HapMap Project; D006801:Humans; D008297:Male; D008875:Middle Aged; D008957:Models, Genetic; D015233:Models, Statistical; D016017:Odds Ratio; D020641:Polymorphism, Single Nucleotide; D012306:Risk; D044465:White People / Q000235:genetics