['Beta1- and beta2-adrenergic receptors (ARs) play a pivotal role in myocardial function. We investigated whether functionally relevant polymorphisms within the genes encoding for these receptors indicate susceptibility to idiopathic dilated cardiomyopathy (DCM).', "This case-control association study involved 189 patients with DCM and 378 gender- and age-matched control subjects. All of the subjects were characterised by polymerase chain reaction-restriction fragment length polymorphism analysis in terms of Ser49Gly and Arg389Gly polymorphisms in the beta1-AR, and the 5' leader cistron Arg19Cys, Arg16Gly, Gln27Glu, and Thr164Ile polymorphisms in the beta2-AR. Genotype, allele and haplotype frequencies were analysed.", 'Univariate analysis showed that the distribution of genotype and allele frequencies of the beta1-Ser49Gly, beta1-Arg389Gly and beta2-Arg16Gly polymorphisms was significantly different between the patients and controls, and the beta1-Gly49/beta1-Arg389 haplotype was significantly more represented in the patients. Multivariate analysis showed that only the beta1-Gly49 variant (odds ratio 1.91; 95% confidence interval 1.24-2.95; P = 0.003) and beta2-Gly16Gly genotype (odds ratio 1.58; 95% confidence interval 1.10-2.26; P = 0.013) carriers were at significantly higher risk of developing DCM.'] Do beta1- and beta2-adrenergic receptor polymorphisms affect susceptibility to idiopathic dilated cardiomyopathy?