title: Synergistic polymorphisms of beta1- and alpha2C-adrenergic receptors and the risk of congestive heart failure.
abstract: BACKGROUND
  Sustained cardiac adrenergic stimulation has been implicated in the development and progression of heart failure. Release of norepinephrine is controlled by negative feedback from presynaptic alpha2-adrenergic receptors, and the targets of the released norepinephrine on myocytes are beta1-adrenergic receptors. In transfected cells, a polymorphic alpha2C-adrenergic receptor (alpha2CDel322-325) has decreased function, and a variant of the beta1-adrenergic receptor (beta1Arg389) has increased function. We hypothesized that this combination of receptor variants, which results in increased synaptic norepinephrine release and enhanced receptor function at the myocyte, would predispose persons to heart failure.
  
  
  METHODS
  Genotyping at these loci was performed in 159 patients with heart failure and 189 controls. Logistic-regression methods were used to determine the potential effect of each genotype and the interaction between them on the risk of heart failure.
  
  
  RESULTS
  Among black subjects, the adjusted odds ratio for heart failure among persons who were homozygous for alpha2CDel322-325 as compared with those with the other alpha2C-adrenergic receptor genotypes was 5.65 (95 percent confidence interval, 2.67 to 11.95; P<0.001). There was no increase in risk with beta1Arg389 alone. However, there was a marked increase in the risk of heart failure among persons who were homozygous for both variants (adjusted odds ratio, 10.11; 95 percent confidence interval, 2.11 to 48.53; P=0.004). The patients with heart failure did not differ from the controls in the frequencies of nine short tandem-repeat alleles. Among white subjects, there were too few who were homozygous for both polymorphisms to allow an adequate assessment of risk.
  
  
  CONCLUSIONS
  The alpha2CDel322-325 and beta1Arg389 receptors act synergistically to increase the risk of heart failure in blacks. Genotyping at these two loci may be a useful approach for identification of persons at risk for heart failure or its progression, who may be candidates for early preventive measures.
authors.affiliation: Division of Pulmonary Medicine, University of Cincinnati College of Medicine, Cincinnati 45267-0564, USA.
authors.forename: Kersten M
authors.initials: KM
authors.lastname: Small
authors.forename: Lynne E
authors.initials: LE
authors.lastname: Wagoner
authors.forename: Albert M
authors.initials: AM
authors.lastname: Levin
authors.forename: Sharon L R
authors.initials: SL
authors.lastname: Kardia
authors.forename: Stephen B
authors.initials: SB
authors.lastname: Liggett
mesh_terms: D000328:Adult; D044383:Black People / Q000235:genetics*; D016022:Case-Control Studies; D005260:Female; D005838:Genotype; D006333:Heart Failure / Q000208:ethnology / Q000235:genetics*; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D009638:Norepinephrine / Q000378:metabolism; D016017:Odds Ratio; D011110:Polymorphism, Genetic; D018341:Receptors, Adrenergic, alpha-2 / Q000235:genetics*; D018342:Receptors, Adrenergic, beta-1 / Q000235:genetics*; D012307:Risk Factors; D016019:Survival Analysis; D044465:White People / Q000235:genetics
chemical_list: C547774:ADRA2C protein, human; D018341:Receptors, Adrenergic, alpha-2; D018342:Receptors, Adrenergic, beta-1; D009638:Norepinephrine