The apolipoprotein(a) size, pentanucleotide repeat, C/T(+93) polymorphisms of apolipoprotein(a) gene, serum lipoprotein(a) concentrations and their relationship in a Korean population

Abstract

BACKGROUND: In addition to apolipoprotein(a) [apo(a)] kringle 4 variable number of tandem repeat (K4-VNTR), pentanucleotide repeat polymorphism (PNRP) and C/T(+93) polymorphism [C/T(+93)] of apo(a) gene have been suggested to be related to lipoprotein(a) [Lp(a)] concentration. We studied the distribution of these genetic polymorphisms and their relationship with Lp(a) concentrations in a Korean population. METHODS: One hundred thirty-two Korean adults were examined. Lp(a) was measured with enzyme-linked immunosorbent assay (ELISA). Apo(a) K4-VNTR was measured by high-resolution SDS-agarose gel separation and ECL Western blotting method. PNRP was measured after DNA amplification. The C/T(+93) ratio was measured by a amplification refractory mutation system. RESULTS: Lp(a) was inversely correlated with K4-VNTR (r=0.732, p<0.0001), but was associated neither with any PNRP haplotype nor with C/T(+93) by multiple regression analysis, although we found a significant decrease of Lp(a) in PNRP 9/9 individuals (p<0.01). There was a strong linkage disequilibrium between 9 haplotypes of PNRP and the T haplotype of C/T(+93). CONCLUSIONS: Inverse relationship between serum Lp(a) and K4 number of apo(a) was confirmed in normal Korean adults. PNRP 9/9 genotype appeared to have a reducing effect on Lp(a), but neither 9 haplotype heterozygotes of PNRP nor the T haplotype C/T(+93) affected Lp(a) concentrations in Koreans.