title: Single-nucleotide polymorphisms in LPA explain most of the ancestry-specific variation in Lp(a) levels in African Americans.
abstract: Lipoprotein(a) (Lp(a)) is an important causal cardiovascular risk factor, with serum Lp(a) levels predicting atherosclerotic heart disease and genetic determinants of Lp(a) levels showing association with myocardial infarction. Lp(a) levels vary widely between populations, with African-derived populations having nearly 2-fold higher Lp(a) levels than European Americans. We investigated the genetic basis of this difference in 4464 African Americans from the Jackson Heart Study (JHS) using a panel of up to 1447 ancestry informative markers, allowing us to accurately estimate the African ancestry proportion of each individual at each position in the genome. In an unbiased genome-wide admixture scan for frequency-differentiated genetic determinants of Lp(a) level, we found a convincing peak (LOD = 13.6) at 6q25.3, which spans the LPA locus. Dense fine-mapping of the LPA locus identified a number of strongly associated, common biallelic SNPs, a subset of which can account for up to 7% of the variation in Lp(a) level, as well as >70% of the African-European population differences in Lp(a) level. We replicated the association of the most strongly associated SNP, rs9457951 (p = 6 × 10(-22), 27% change in Lp(a) per allele, ∼5% of Lp(a) variance explained in JHS), in 1,726 African Americans from the Dallas Heart Study and found an even stronger association after adjustment for the kringle(IV) repeat copy number. Despite the strong association with Lp(a) levels, we find no association of any LPA SNP with incident coronary heart disease in 3,225 African Americans from the Atherosclerosis Risk in Communities Study.
authors.affiliation: Department of Genetics, Harvard Medical School, Boston, Massachusetts, United States of America. rdeo@partners.org
authors.forename: Rahul C
authors.initials: RC
authors.lastname: Deo
authors.forename: James G
authors.initials: JG
authors.lastname: Wilson
authors.forename: Chao
authors.initials: C
authors.lastname: Xing
authors.forename: Kim
authors.initials: K
authors.lastname: Lawson
authors.forename: W H Linda
authors.initials: WH
authors.lastname: Kao
authors.forename: David
authors.initials: D
authors.lastname: Reich
authors.forename: Arti
authors.initials: A
authors.lastname: Tandon
authors.forename: Ermeg
authors.initials: E
authors.lastname: Akylbekova
authors.forename: Nick
authors.initials: N
authors.lastname: Patterson
authors.forename: Thomas H
authors.initials: TH
authors.lastname: Mosley
authors.forename: Eric
authors.initials: E
authors.lastname: Boerwinkle
authors.forename: Herman A
authors.initials: HA
authors.lastname: Taylor
mesh_terms: D001741:Black or African American / Q000235:genetics*; D044383:Black People / Q000235:genetics; D002318:Cardiovascular Diseases / Q000235:genetics; D056426:Genetic Loci / Q000235:genetics*; D005819:Genetic Markers; D006801:Humans; D018082:Kringles / Q000235:genetics; D017270:Lipoprotein(a) / Q000097:blood / Q000235:genetics*; D020641:Polymorphism, Single Nucleotide / Q000235:genetics*; D044465:White People / Q000235:genetics
chemical_list: D005819:Genetic Markers; D017270:Lipoprotein(a)