Sequence microheterogeneity in apolipoprotein(a) gene repeats and the relationship to plasma Lp(a) levels

Francesco P. Mancini, Vincent Mooser, Rudy Guerra, Helen H. Hobbs

Research output: Contribution to journalArticle

39 Scopus citations

Abstract

Lipoprotein(a) [Lp(a)] is a cholesterol ester-rich atherogenic lipoprotein that is composed of a particle of low density lipoprotein and a large glycoprotein, apolipoprotein(a) [apo(a)]. Apolipoprotein(a) varies in size over a ̃500 kDa range due to inter-allelic differences in the number of tandemly repeated kringle 4 (K4)-encoding 5. 5 kb sequences in the apo(a) gene. Only one of the 10 different types of K4 repeats in the apo(a) gene, the so-called type 2 K4 repeats, vary in number between apo(a) alleles. In this paper, we show that there is microheterogeneity within the sequence of the type 2 K4 repeat. Dralll restriction digestion and genomic blotting revealed that a subset of the type 2 K4-encoding sequences contained a Dralll site (K4-D). The proportion of apo(a) alleles that had at least one K4-D repeat ranged from 25% in Caucasians to 50% in the Chinese. K4-D repeats were clustered at the end(s) of the type 2 K4 tandem array and the number and patterns of the K4-D repeats were in linkage disequilibrium with flanking sequence polymorphisms; these features are remarkably similar to the minisatellite variant repeats (MVRs) found in variable number of tandem repeat sequences (VNTRs). In addition, a Dralll pattern that comprised 9% of the sample was invariably associated with low plasma levels of Lp(a) in Caucasians.

Original languageEnglish (US)
Pages (from-to)1535-1542
Number of pages8
JournalHuman molecular genetics
Volume4
Issue number9
DOIs
StatePublished - Sep 1 1995

ASJC Scopus subject areas

  • Molecular Biology
  • Genetics
  • Genetics(clinical)

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