Angiotensin II type I receptor gene polymorphism in essential hypertensive and normotensive subjects

Abstract

Hypertension is a polygenic disorder that involves a complex interplay of genetic and environmental factors. Genes that influence the renin–angiotensin–aldosterone system (RAAS) appear to be particularly important among the many potential candidate components of EHT. The RAAS system plays an important role in BP regulation by maintaining vascular tone and renal hemodynamics. Most of these are mediated via the activation of the angiotensin II type 1 receptor (AT1R). Untreated hypertension increases the risk of developing cardiovascular diseases such as stroke, myocardial infarction, ischemic heart disease, and, target organ damage. A polymorphism in the 3’ untranslated region of the AT1R gene has been described with either an adenine (A) or a cytosine (C) base (A/C transversion) at the 1166 position that is associated with increased blood pressure. A total of 170 hypertensive patients and 170 normal subjects were included in the present study. Genomic DNA was isolated from peripheral blood leukocytes, amplified with PCR, and separated with gel electrophoresis to determine the AT1R genotype. On electrophoresis, the genotypes A/A-359 bp, A/C-220+139 bp, and C/C-220, 139, and 359 bp were identified. In hypertensive patients, the CC genotype was present in 21.18 percent (n = 36) as compared to 11.76 percent (n = 20) in non-hypertensive patients. In this study AT1R CC homozygote was significantly associated with hypertension (p = 0.019). The odds ratio related to the association of the prevalence of the CC genotype with hypertension was 2.014 (95% CI: 1.112–3.650).: From the present study, it is concluded that AT1R gene polymorphism is associated with hypertension, and with the CC genotype, the risk of hypertension increases in comparison to AC and AA. A allele is not significantly associated with hypertension, but the recessive and co-dominant modes of inheritance of allele C (CC) and its co-dominant mode (AC) are a genetic predisposition to hypertension.