The angiotensin-converting enzyme (ACE) gene insertion/deletion dimorphismtracks with higher serum ACE activities in both younger and older subjects

Background: The absence of a 287 base pair alu sequence in the ACE gene (D allele) is associated with higher ACE levels than its presence (I allele) i n adults. We carried out a case-control study of the ACE*I/D dimorphism in relation to circulating ACE activities to evaluate associations between the two variables in adults, compared to younger(18 years or less) individuals . Materials and Methods: Genotypes of the ACE*I/D dimorphism were determined on DNA samples from a population of 164 random (unrelated) Emirate national s, composed of two groups: 112 subjects above 18 years of age (range=20-77 years), and 52 subjects of 18 years or less (range=1-18), and analyzed for putative associations with serum ACE activities. ACE*I/D genotypes of the 1 64 individuals were determined by assays based on polymerase chain reaction . ACE activities were determined on serum samples of these subjects by colo rimetric assays. Results: The D allele was associated with increased ACE values in both adul t and younger individuals. Mean ACE activity levels associated with II, ID and DD genotypes, however, were 42%-61% higher in the 18 years and under gr oup of subjects. The ACE*I/D marker accounted for 28% of the variance of th e phenomenon determining ACE levels in adults, and for 30% among youngsters . Conclusion: The ACE*I/D dimorphism correlated strongly with circulating ACE activities in both adult and young Emirati subjects, and the corresponding mean ACE activities were significantly higher among the youngsters.