Polymorphisms of Adrenergic Receptors and the Risk of Heart Failure

To the Editor: The interesting study by Small et al. (Oct. 10 issue) 1 showed that two potentially synergistic adrenergic-receptor polymorphisms are associated with a risk of congestive heart failure. Since this may indeed give rise to genotype-targeted intervention studies, one important point deserves attention. Although the polymorphism involving the substitution of glycine for arginine at position 389 (Arg389Gly) of the β 1 -adrenergic receptor has clearly been shown to be functional in vitro, data on its consequences in vivo are conflicting. 2 Moreover, there is high sequence variability in the gene encoding the β 1 -adrenergic receptor, with at least 18 . . .