Variation at the Beta-1Adrenoceptor Gene Locus is Associated with Left Ventricular Mass in Endurance Athletes

Abstract

0714 Left ventricular hypertrophy in response to endurance training is a common feature in athletes. Twin studies, as well as association studies have shown that genetic factors play a role in the determination of the so called athlete's heart. In two recent studies, variants of the gene encoding the Beta-1 adrenoceptor (B1AR) has been associated with enlargement of the left ventricle in two different cohorts of sedentary subjects. PURPOSE: The aim of our study was to investigate the role of B1AR genetic polymorphisms for the development of left ventricular hypertrophy in endurance athletes. METHODS: We studied a cohort of 198 male Caucasian athletes involved in different endurance sports with a training history of at least 5 years (Tab. 1). Left ventricular mass was determined using M-mode echocardiography. Left ventricular mass index (LVMI) was calculated using Devereux's formula with correction for the body surface area. Subjects were typed for two single nucleotide polymorphisms (SNPs) that result in serine/glycine (Ser49Gly) and arginine/glycine (Arg389Gly) amino acid substitutions at residues 49 and 389 in the B1AR gene, respectively.Tab. 1: Characteristics of subjects (mean +/− std)RESULTS: Genotype distributions for both polymorphisms were in Hardy-Weinberg equilibrium. A significant association was found for Ser49Gly genotype and LVM (p = 0.036). Further analysis revealed a higher LVMI in carriers of the Gly-Allele compared to subjects homozygote for the Ser-Allele (LVMI 154g/m-2 vs. 145g/m-2, p = 0.014). No association was seen between the Arg389Gly polymorphism and LVM or LVMI (p = 0.093 and 0.232, respectively). CONCLUSION: In summary, we found evidence that the Ser49Gly polymorphism in the gene encoding for the B1AR may play a role in the development of left ventricular hypertrophy in highly trained endurance athletes.