Background: The angiotensin-converting enzyme gene and the angiotensin II type 1 receptor gene meet the criteria for candidate genes in the pathogenesis of essential hypertension. The aim of this study was to assess the possible association between polymorphisms of these genes and essential hypertension in a Polish population, to evaluate them as possible genetic markers of susceptibility to hypertension, and to search for interaction between the two polymorphisms.
Material and methods: The insertion/deletion polymorphism at the angiotensin-converting enzyme gene locus and the A1166C polymorphism at the angiotensin II type 1 receptor gene locus were detected using the polymerase chain reaction and restriction fragment length methods. 250 patients with stable essential hypertension lasting at least 1 year were compared to 150 individuals without signs and symptoms of cardiovascular disease or family history of hypertension.
Results: No association was found between the insertion/deletion polymorphism at the angiotensin-converting enzyme locus and essential hypertension in the study population, although the DD genotype occurred more often (p<0.01) among patients with hypertension and a negative family history of hypertension than among hypertensives with a positive family history. There was an association in our study population between hypertension and the A1166C polymorphism at the angiotensinogen II type 1 receptor gene locus. The frequency of occurrence of the C1166 variant was higher among patients with hypertension (0.29) than in control subjects (0.20). The CC genotype occurred more frequently among hypertensives (0.10) than in the control group (0.04). Both these differences were statistically significant. This association was stronger in males, patients with a negative family history of hypertension, and non-obese patients with a body mass index less than 26 kg/m2. To test the interaction between the polymorphisms in question, the distribution of the A1166 and C1166 variants among ACE genotypes was assessed. The A1166 variant occurs more often among DD genotype normotensives.
Conclusions: There was no association in our study population between essential hypertension and the I/D polymorphism at the angiotensin-converting enzyme gene locus. The C1166 variant of the angiotensin II type 1 receptor gene was associated with hypertension in our study population, while the A1166 variant seems to be protective as regards susceptibility to hypertension.