RACIAL DIFFERENCE IN THE RELATIONSHIP OF AN ANGIOTENSIN I-CONVERTING ENZYME GENE POLYMORPHISM TO SERUM ANGIOTENSIN I-CONVERTING ENZYME-ACTIVITY

An insertion (I)/deletion (D) polymorphism of the angiotensin I-conver ting enzyme (ACE) gene that has been associated with certain cardiovas cular disorders accounts for nearly half the variation in serum ACE le vel in white subjects. Whether a similar association of serum ACE with the I/D polymorphism occurs in other racial groups is not known. We s tudied the I/D polymorphism of ACE in relation to serum ACE activity i n 141 white and 62 black healthy, unrelated children and adolescents ( mean age, 14.7 years). The mean level of ACE activity in whites homozy gous for the D allele was higher than in heterozygotes (P=.002) and in homozygotes for the I allele (P=.0001), consistent with an earlier st udy. Inblacks, on the other hand, no significant difference in serum A CE activity between genotypes was observed. An additional finding was a significantly positive relationship between serum ACE activity and d iastolic pressure (P=.009). In children and adolescents, serum ACE act ivity is related to the ACE gene I/D polymorphism in whites but not in blacks. The results indicate a potentially important ethnic variation in genetic regulation of serum ACE activity and the relationship of t he I/D polymorphism to cardiovascular disease.