Differences in Lpa concentrations and apoa polymorphs between black and white Americans

Lpa concentrations in nmol/L and apoa size isoforms, expressed in terms of the relative number of apoa kringle 4 (K4) repeats, were determined in 3959 whites and blacks from four U.S. communities. Plasma Lpa analyses were performed by an ELISA method insensitive to apoa size heterogeneity and apoa size isoforms were determined by high resolution agarose gel electrophoresis. Allele frequencies were estimated by maximum likelihood methods in order to account for the presence of null alleles and coalescence of hands on gels. The apoa allele frequencies and phenotype distributions differed significantly between blacks and whites (P 31 K4 repeats) both blacks and whites exhibited uniformly low Lpa values. For the intermediate isoforms K4(20) through K4(30), a considerable range of Lpa values was evident in blacks; the median Lpa for each isoform increased nearly linearly as the apoa size decreased. In contrast in whites there was little change in median Lpa concentrations for isoforms K4(20) through K4(30). For the small apoa size (< 20 K4) both blacks and whites exhibited high median Lpa levels and a wide variation of Lpa levels. The major difference in Lpa levels between the two racial groups occurred in the intermediate size isoform range of K4(20) through K4(25). In conclusion, whites and blacks differ significantly in Lpa concentrations, allele and phenotype frequencies, and in the relationship between apoa size isoform and Lpa concentration.