ABSTRACT
Background : Although the Beta1-adrenoreceptor (AR) Gly389Arg and ?2c-AR Del322-325 gene variants are associated with the response to Beta-AR-blocker therapy; whether this effect is associated with the risk for heart failure; or the severity or progression of heart failure is uncertain. Aims : To assess the relationship between Gly389Arg and Del322-325 variants and the presence; severity and progression of idiopathic dilated cardiomyopathy (IDC) in 403 black South African patients. Methods : Genotypes were identified using a restriction fragment length olymorphism-based technique and automated sequencing. Left ventricular ejection fraction (LVEF) and dimensions were determined at baseline and in 132 patients after six months of standard medical therapy excluding Beta- AR-blockers (not indicated as standard care at the time of completing this study). Results : All patients and controls genotyped for the ?2c-AR variant were homozygous for the Del322-325 (risk) allele. The Gly389Arg polymorphism was not associated with IDC (control n = 429) (Arg389 allele homozygosity : odds ratio = 1.03; confidence limits = 0.78-1.35); nor did it predict LVEF and cavity dimensions either before or after therapy. Conclusion : in patients homozygous for the risk allele of the ?2c-AR variant; the Beta1-AR variant neither increased the risk for IDC nor predicted its severity or progression in patients not receiving Beta-AR-blockers