POLYMORPHISM OF THE ANGIOTENSIN-I CONVERTING-ENZYME GENE IN ESSENTIALHYPERTENSIVE PATIENTS

Insertion/deletion (I/D) polymorphism of the angiotensin I converting enzyme (ACE) gene has been associated with ischemic heart disease and hypertension. The D allele reportedly correlates with myocardial infar ction and it has been suggested that it may serve as the basis of popu lation-based risk assessment. Similarly, determining whether there is an ACE allele pattern associated with hypertension could be useful in developing screening strategies. Previous reports have not shown consi stent findings in Caucasian and Japanese population groups, some havin g a predominance of the I allele. Although African Americans have the highest prevalence of hypertension in the world, their ACE gene polymo rphism frequencies have not been clearly defined. We studied the allel e and genotype frequencies in this group, consisting of 133 essential hypertensive subjects, and compared their findings with those reported from normotensive African Americans and from other racial groups. The black patients had a different allele distribution than the other pop ulations in that the D was more common than the I allele, occurring at a rate of 59.7%. The most common genotype was DD and it was present i n 42.5% of the hypertensive subjects in contrast to the ID genotype wh ich was the most commonly reported genotype in normotensive individual s, The genotype pattern (frequencies of II, ID, DD) was significantly different (p<0.005, 2 df) from Japanese and Caucasian (Scotland and Au stralia) populations. There was no common allele or genotype distribut ion amongst these diverse hypertensive groups. In summary, African Ame ricans with essential hypertension most commonly have the D allele ACE gene polymorphism and the DD genotype; however, investigators need to be aware that there are major population differences in the allele an d genotype frequencies and this could make the polymorphisms a problem atic screening tool for hypertension.