Apo[a] size and PNR explain African American-Caucasian differences in allele-specific apo[a] levels for small but not large apo[a]

Jill Rubin, Jo Kim Han, Thomas A. Pearson, Steve Holleran, Rajasekhar Ramakrishnan, Lars Berglund

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22 Scopus citations


Apolipoprotein [a] (apo[a]) gene size is a major predictor of lipoprotein [a] level. To determine genetic predictors of allele-specific apo[a] levels beyond gene size, we evaluated the upstream C/T and pentanucleotide repeat (PNR) polymorphisms. We determined apo[a] sizes, allelespecific apo[a] levels, and C/T and PNR in 215 Caucasians and 139 African Americans. For Caucasians, apo[a] size affected allele-specific levels substantially greater in subjects with apo[a] < 24 K4; for African Americans, the size effect was smaller than in Caucasians, <24 K4, but did not decrease at higher repeats. In both groups, the level decreased with increasing size of the other allele. Controlling for apo[a] sizes, PNR decreased allele-specific apo[a] levels in Caucasians with increasing PNR > 8. In a multiple regression model, apo[a] allele size and size and expression of the other apo[a] allele (and PNR > 8 for Caucasians) significantly predicted allele-specific apo[a] levels. For a common PNR 8 allele, predicted values were similar in the two ethnicities for small size apo[a]. Allele-specific apo[a] levels were influenced by the other allele size and expression. Observed differences between Caucasians and African Americans in allele-specific apo[a] levels were explained for small apo[a] sizes by the other allele size and PNR; the ethnicity differences remain unexplained for larger sizes.

Original languageEnglish (US)
Pages (from-to)982-989
Number of pages8
JournalJournal of Lipid Research
Issue number5
StatePublished - May 2006



  • African Americans
  • Apolipoprotein [a]
  • Genotyping
  • Lipoprotein [a]
  • Pentanucleotide repeat
  • Polymorphism

ASJC Scopus subject areas

  • Endocrinology

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