Single nucleotide polymorphisms (SNPs) within the β(1)- (Ser49Gly, Arg389Gly) and β(2)-adrenoceptor (Arg16Gly, Gln27Glu, Thr164Ile) have been associated with alterations in adrenoceptor (AR) function sensitivity in vitro and in vivo and possibly contribute to HF progression.
The prevalence of the hypofunctional Thr164Ile</span>-beta(2)AR variant and the frequency of the Ile164-allele were almost identical in CHF-patients, who had undergone HTX, with those in patients with stable CHF or in healthy controls.
Of particular importance, the Thr164Ile polymorphism, which is found in approximately 4% of humans, shows decreased receptor signaling, blunted cardiac response when expressed in transgenic mice, and is associated with a decreased survival rate in patients with congestive heart failure.