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.
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.
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.