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 E*4 allele as compared to the reported values in other population groups. The frequencies of the three alleles, APO E*2, APO E*3, and APO E*4, respectively, are: 0.034, 0.706, 0.260 in U.S. Blacks and 0.028, 0.662, 0.310 in Nigerian Blacks.