Research article

Association of alpha1a-adrenergic receptor polymorphism and blood pressure phenotypes in the Brazilian population

Silvia R Freitas^1,2 , Alexandre C Pereira¹ , Marcilene S Floriano¹ , José G Mill³ and José E Krieger¹

¹  Laboratory of Genetics and Molecular Cardiology, Heart Institute/InCor, University of São Paulo Medical School, São Paulo, Brazil

²  Laboratory of Human Genetics, Oswaldo Cruz Institute/FIOCRUZ, Rio de Janeiro, Brazil

³  Department of Physiology, Espírito Santo Federal University, Vitória, Brazil

author email corresponding author email

BMC Cardiovascular Disorders 2008, 8:40doi:10.1186/1471-2261-8-40

Published:	23 December 2008

Abstract

Background

The alpha1A-adrenergic receptor (α_1A-AR) regulates the cardiac and peripheral vascular system through sympathetic activation. Due to its important role in the regulation of vascular tone and blood pressure, we aimed to investigate the association between the Arg347Cys polymorphism in the α_1A-AR gene and blood pressure phenotypes, in a large sample of Brazilians from an urban population.

Methods

A total of 1568 individuals were randomly selected from the general population of the Vitória City metropolitan area. Genetic analysis of the Arg347Cys polymorphism was conducted by polymerase chain reaction/restriction fragment length polymorphism. We have compared cardiovascular risk variables and genotypes using ANOVA, and Chi-square test for univariate comparisons and logistic regression for multivariate comparisons.

Results

Association analysis indicated a significant difference between genotype groups with respect to diastolic blood pressure (p = 0.04), but not systolic blood pressure (p = 0.12). In addition, presence of the Cys/Cys genotype was marginally associated with hypertension in our population (p = 0.06). Significant interaction effects were observed between the studied genetic variant, age and physical activity. Presence of the Cys/Cys genotype was associated with hypertension only in individuals with regular physical activity (odds ratio = 1.86; p = 0.03) or younger than 45 years (odds ratio = 1.27; p = 0.04).

Conclusion

Physical activity and age may potentially play a role by disclosing the effects of the Cys allele on blood pressure. According to our data it is possible that the Arg347Cys polymorphism can be used as a biomarker to disease risk in a selected group of individuals.