Angiotensin II AT1 receptor gene polymorphism and microalbuminuria in essential hypertension

The objective of this study was to analyze the relationship of polymorphism s of the angiotensin II ATI receptor gene with microalbuminuria in a group of young adults with essential hypertension. Essential hypertensives, less than 50 years old, never previously treated with antihypertensive drugs, an d in absence of diabetes mellitus were included. Office blood pressure (BP) , 24-h ambulatory BP monitoring, urinary albumin excretion (UAE) measuremen ts, and DNA analysis were performed. Polymorphisms of the angiotensin II AT 1-receptor gene (A1166C and C573T) were studied by polymerase chain reactio n and single-strand conformation polymorphism techniques. One hundred eight y-three patients, 49 (27%) microalbuminurics, were included. Office and amb ulatory BP values were significantly higher in the microalbuminuria group. No differences in the presence of microalbuminuria were observed among the genotypes of either A1166C or C573T polymorphisms of the angiotensin II rec eptor AT1 gene, or in the allele frequency of the A1166C or the C573T polym orphism LogUAE was significantly different among genotypes of the C573T pol ymorphism [CC 1.30(1.15-1.45), CT 1.14(1.00-1.28), and TT 0.94(0.68-1.20), P < .05]. Both office and ambulatory blood pressure and the TT/C573T genoty pe were independently related to logUAE, and, at the same BP values, UAE wa s lower in subjects with this genotype. We have found that the C573T polymo rphism is on linkage disequilibrium with A1166C, as the 573T allele is clos ely linked to the presence of the 1166A allele, but not vice versa. Haploty pe analysis among subjects with the AA genotype for the A1166C polymorphism confirms the influence of the TT genotype of the C573T polymorphism on the UAE in hypertensives. The C573T polymorphism of the angistensin II recepto r ATI gene seems to be a genetic protective factor for UAE in a population of essential hypertensives. <(c)> 2001 American Journal of Hypertension, Lt d.