RESUMO
BACKGROUND: The human angiotensin-converting enzyme (ACE) gene contains a polymorphism consisting of either an insertion (I) or a deletion (D) of a 287 bp Alu repetitive sequence in intron 16. The potential role of ACE polymorphism in the risk of developing hypertension or other cardiovascular disorders has not been determined in relation to birth weight (BW). METHODS: The ACE genotype and plasma ACE activity were determined in 167 children. Among these children, 60 were identified with low BW (LBW), and 107 were of normal BW (NBW). RESULTS: ACE activity levels were significantly elevated in LBW children compared with the NBW group (P < 0.001). There was a significant association of the ACE activity with systolic blood pressure (SBP) levels in our population (P < 0.001). Among the ACE genotypes, no significant differences were found with respect to BW (P = 0.136). However, our results revealed that LBW children had a higher D allele frequency than NBW children (P = 0.036). When analyzed by quartiles of SBP or ACE activity, we found a greater frequency of both the LBW children and those carrying the DD genotype in the highest quartiles of these parameters, whereas the NBW children tended to be in the lowest quartile (P < 0.001). Similar results were observed with the heterozygote ID children after categorization by quartiles of both SBP (P < 0.001) and ACE activity (P = 0.004). CONCLUSIONS: The ACE I/D polymorphism, especially the DD genotype, can be interpreted as a major factor in association between LBW and high BP levels.