Genetic studies of human apolipoproteins. VI. Common polymorphism of apolipoprotein E in blacks.

Human apolipoprotein E exhibits genetically determined polymorphism with three common alleles, and plays a pivotal role in lipoprotein metabolism. Except in Caucasians, variation at the apolipoprotein E locus has been studied poorly in world populations. Using isoelectric focusing and immunoblotting, we have determined apolipoprotein E phenotypes and gene frequencies in a large number of individuals of black ancestry from the U.S. and Nigeria. The common three allele polymorphism was observed in both populations, with a striking high frequency of the APO E4 allele as compared to the reported values in other population groups. The frequencies of the three alleles, APO E2, APO E3, and APO E4, respectively, are: 0.034, 0.706, 0.260 in U.S. Blacks and 0.028, 0.662, 0.310 in Nigerian Blacks.