Angiotensin converting enzyme gene polymorphism and activity in Turkish patients with essential hypertension

Studies in various ethnic groups have shown contradictory evidence on the a ssociation of: the angiotensin converting enzyme (ACE) insertion/ deletion (I/D) polymorphism with essential hypertension. We conducted a case-control study in Samsun, Turkey, to examine the association between ACE genotype, ACE serum activity, and blood pressure. Serum ACE activity was measured and ACE I/D polymorphism performed in 165 hypertensive and 143 normotensive su bjects. Genomic DNA was extracted from blood samples and amplified by polym erase chain reaction (PCR), PCR primers were flanking the polymorphic regio n in intron 16 of the ACE gene. The distribution of the DD, ID, and II ACE genotypes was 65, 77, and 23 in hypertensive patients and 42, 82, and 19 in normotensive subjects (P > .05). The estimated frequency of the insertion allele was 0.37 in hypertensive and 0.42 in normotensive subjects. Neverthe less, sensitivity analysis, based on positive family history and severity o f hypertension, suggested that significant associations existed between mor e homogeneous groups of hypertensives and normotensives (P < .05). ACE geno type influenced ACE activity and the highest level was in DD genotype, bein g the lowest in II genotype. ACE serum levels were significantly higher in hypertensives as compared with normotensives (P < .01). A modest correlatio n was observed between blood pressure and ACE among hypertensive persons (r = 0.25, P < .05) and this did persist in multivariate analysis (P < .05 fo r systolic blood pressure and P < .005 for diastolic blood-pressure). These data suggest that ACE DD genotype may have predisposing effects on severe hypertensives and cases with positive family history, and that ACE may be o ne of the independent factors on hypertension. (C) 1999 American Journal of Hypertension, Ltd.