Apolipoprotein(a) genotypes in a Scandinavian population: Allele frequencies, correlation to apolipoprotein(a) phenotypes and lipoprotein(a) concentrations

Background and Aim: We have studied the distribution of apo(a) KpnI alleles and their relationship to Lp(a) concentrations and apo(a) protein phenotypes in 455 forty-year-old Danish men. Methods and Results: The distribution of apo(a) alleles was similar to that described in a Tyrolean population, and the size of the apo(a) alleles was inversely correlated to Lp(a) concentrations. When comparing results of apo(a) KpnI genotyping and apo(a) protein phenotyping by SDS-PAGE the major differences were that subjects with single-banded protein isoform detected by Western blotting, had an allele coding for S4, too. In agreement with these findings the majority of the 0 (null) isoforms had two apo(a) alleles that coded for S4 protein isoforms. Even though most of the apo(a) alleles associated with no detectable apo(a) protein were relatively large, they were distributed over the entire apo(a) allele size range. Conclusions: When comparing the distribution of apo(a) protein phenotypes and apo(a) KpnI alleles in two groups according to protein size and allele size, respectively, we found no difference between the distributions and the median Lp(a) concentrations in the groups, suggesting that the use of apo(a) KpnI genotyping would not have changed the results of previous studies comparing apo(a) allele distributions by SDS-polyacrylamide gel electrophoresis. (C) 1997, Medikal Press.