Background: The goal of this study was to analyse the association between essential hypertension and the main genetic polymorphisms at the renin-angiotensin system in the Spanish population.
Patients and method: Case-control study including 185 essential hypertensive subjects(age [SD] 39.6 [7.5] years, 52% women, systolic blood pressure 151.2 [17.4] mmHg, diastolic blood pressure 96.0 [9.4] mmHg) and 350 sex- and age-matched normotensive individuals selected from a sample of the general population of the Comunidad Valenciana, Spain (age 39.4 [8.0] years, 51.7% women, systolic blood pressure 116.0 [12.0] mmHg, diastolic blood pressure 69.6 [8.5] mmHg). A PCR was performed to determine I/D angiotensin converting enzyme (ACE) gene polymorphism, A-6G and M235T angiotensinogen gene polymorphism and A1166C polymorphism of the angiotensin II type 1 receptor.
Results: There were no differences between cases and controls with regard to genotypic and allelic distributions. In hypertensive patients,there were no differences in genotypic or allelic distributions after considering the presence or absence of a familial history of hypertension or comparing tertiles of systolic and diastolic blood pressure values. Only in women, the combination of a C allele of A1166C polymorphism with an A-6G angiotensinogen polymorphism A allele (p = 0.007), or an M235T angiotensinogen polymorphism T allele (p = 0.007), was associated with a higher risk of hypertension.
Conclusions: We found no association between essential hypertension risk and I/D ACE gene, M235T and A-6G angiotensinogen gene, or A1166C angiotensin II type 1 receptor gene polymorphisms. An epistatic effect was observed in young women between angiotensin II type 1 receptor polymorphisms and angiotensinogen polymorphisms.