Differences in frequency of the deletion polymorphism of the angiotensin-converting enzyme gene in different ethnic groups

A polymorphism characterized by the insertion or deletion of a 287-bp Alu r epeat sequence in intron 16 of the angiotensin-converting enzyme gene deter mines about half the serum angiotensin-converting enzyme level variability among individuals. The deletion polymorphism is associated with higher leve ls of angiotensin-converting enzyme and perhaps with a greater risk of card iovascular diseases. The relative frequency of this genetic polymorphism in different ethnic groups is not known. The objective of this study was to c ompare the frequency of angiotensin-converting enzyme gene insertion/deleti on polymorphism in different ethnic groups. Angiotensin-converting enzyme g enotype was determined in middle-aged healthy hospital workers of three dif ferent ethnic origins (African Americans, whites, and Indians). There were 142 African Americans, 136 Indians, and 82 whites. The distribution of the deletion-deletion, insertion-deletion, and insertion-insertion genotypes in African Americans (29%, 60%, and 11%, respectively), Indians (19%, 50%, an d 31%, respectively) and whites (29%, 40%, and 31%, respectively) was signi ficantly different (p = < 0.005). The frequency of the deletion allele amon g African Americans, Indians, and whites (0.59, 0.49, and 0.44, respectivel y) was also significantly different (p = 0.05). African Americans had the h ighest frequency of deletion allele and the lowest frequency of the inserti on-insertion genotype among the three groups. The frequency of the deletion polymorphism of the angiotensin-converting enzyme gene is different among African Americans, whites, and Indians. This may be important in relation t o the high risk of cardiovascular morbidity and mortality in African Americ ans and may be relevant in explaining differences in cardiovascular disease s in different populations. This finding also emphasizes the importance of studying angiotensin-converting enzyme gene polymorphism in genetically hom ogenous populations, Because of the small size of this study, however. thes e findings need further confirmation.