Angiotensin II Type 1 Receptor A/C 1166 Polymorphism

Abstract

The angiotensin II type 1 (AT 1 ) receptor has a key role in mediating the vasoconstrictor and growth-promoting effects of angiotensin II. It has been reported that a polymorphism of the AT 1 receptor gene (an A/C transversion at position 1166) may be associated with cardiovascular phenotypes, such as arterial blood pressure and aortic stiffness, that underlie a condition of increased cardiovascular risk. We examined a sample of 212 subjects randomly selected from a general population in northern Italy to investigate the role of AT 1 receptor gene polymorphism in the regulation of blood pressure and cardiovascular growth. We measured blood pressure (both clinic and 24-hour ambulatory recording), left ventricular mass (echocardiography), and carotid artery wall thickness (B-mode ultrasound); we assessed the AT 1 receptor genotype by polymerase chain reaction and allele-specific oligonucleotide hybridization. Blood pressure values were lower in CC homozygotes than in heterozygotes and AA homozygotes; the difference was statistically significant for clinic measurements (mean difference for mean blood pressure, −6.6 mm Hg, P =.01; 95% confidence interval, −1.6 to −11.7 mm Hg) but not for ambulatory blood pressure measurements. CC homozygotes also presented a lower incidence of a positive family history of hypertension ( P =.027). No statistically significant differences among AT 1 receptor A/C 1166 genotypes were observed for left ventricular mass or carotid artery wall thickness. We conclude that the present study does not support a major role of the AT 1 receptor gene A/C 1166 polymorphism as a marker of conditions associated with increased cardiovascular risk.