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Fine-mapping in African Americans of 8 recently discovered genetic loci for plasma lipids: the Jackson Heart Study.

ABSTRACT: BACKGROUND:Genome-wide association studies in cohorts of European descent have identified novel genomic regions as associated with lipids, but their relevance in African Americans remains unclear. METHODS AND RESULTS:We genotyped 8 index single nucleotide polymorphisms (SNPs) and 488 tagging SNPs across 8 novel lipid loci in the Jackson Heart Study, a community-based cohort of 4605 African Americans. For each trait, we calculated residuals adjusted for age, sex, and global ancestry and performed multivariable linear regression to detect genotype-phenotype association with adjustment for local ancestry. To explore admixture effects, we conducted stratified analyses in individuals with a high probability of 2 African ancestral alleles or at least 1 European allele at each locus. We confirmed 2 index SNPs as associated with lipid traits in African Americans, with suggestive association for 3 more. However, the effect sizes for 4 of the 5 associated SNPs were larger in the European local ancestry subgroup compared with the African local ancestry subgroup, suggesting that the replication is driven by European ancestry segments. Through fine-mapping, we discovered 3 new SNPs with significant associations, 2 with consistent effect on triglyceride levels across ancestral groups: rs636523 near DOCK7/ANGPTL3 and rs780093 in GCKR. African linkage disequilibrium patterns did not assist in narrowing association signals. CONCLUSIONS:We confirm that 5 genetic regions associated with lipid traits in European-derived populations are relevant in African Americans. To further evaluate these loci, fine-mapping in larger African American cohorts and/or resequencing will be required.

SUBMITTER: Keebler ME

PROVIDER: S-EPMC3074173 | biostudies-literature | 2010 Aug

REPOSITORIES: biostudies-literature

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Fine-mapping in African Americans of 8 recently discovered genetic loci for plasma lipids: the Jackson Heart Study.

Keebler Mary E ME Deo Rahul C RC Surti Aarti A Konieczkowski David D Guiducci Candace C Burtt Noel N Buxbaum Sarah G SG Sarpong Daniel F DF Steffes Michael W MW Wilson James G JG Taylor Herman A HA Kathiresan Sekar S

Circulation. Cardiovascular genetics 20100622 4

<h4>Background</h4>Genome-wide association studies in cohorts of European descent have identified novel genomic regions as associated with lipids, but their relevance in African Americans remains unclear.<h4>Methods and results</h4>We genotyped 8 index single nucleotide polymorphisms (SNPs) and 488 tagging SNPs across 8 novel lipid loci in the Jackson Heart Study, a community-based cohort of 4605 African Americans. For each trait, we calculated residuals adjusted for age, sex, and global ancestr ...[more]

PMID: 20570916

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Project description:The QT interval (QT) is heritable and its prolongation is a risk factor for ventricular tachyarrhythmias and sudden death. Most genetic studies of QT have examined European ancestral populations; however, the increased genetic diversity in African Americans provides opportunities to narrow association signals and identify population-specific variants. We therefore evaluated 6,670 SNPs spanning eleven previously identified QT loci in 8,644 African American participants from two Population Architecture using Genomics and Epidemiology (PAGE) studies: the Atherosclerosis Risk in Communities study and Women's Health Initiative Clinical Trial. Of the fifteen known independent QT variants at the eleven previously identified loci, six were significantly associated with QT in African American populations (P?1.20×10(-4)): ATP1B1, PLN1, KCNQ1, NDRG4, and two NOS1AP independent signals. We also identified three population-specific signals significantly associated with QT in African Americans (P?1.37×10(-5)): one at NOS1AP and two at ATP1B1. Linkage disequilibrium (LD) patterns in African Americans assisted in narrowing the region likely to contain the functional variants for several loci. For example, African American LD patterns showed that 0 SNPs were in LD with NOS1AP signal rs12143842, compared with European LD patterns that indicated 87 SNPs, which spanned 114.2 Kb, were in LD with rs12143842. Finally, bioinformatic-based characterization of the nine African American signals pointed to functional candidates located exclusively within non-coding regions, including predicted binding sites for transcription factors such as TBX5, which has been implicated in cardiac structure and conductance. In this detailed evaluation of QT loci, we identified several African Americans SNPs that better define the association with QT and successfully narrowed intervals surrounding established loci. These results demonstrate that the same loci influence variation in QT across multiple populations, that novel signals exist in African Americans, and that the SNPs identified as strong candidates for functional evaluation implicate gene regulatory dysfunction in QT prolongation.

Dataset Information

Fine-mapping in African Americans of 8 recently discovered genetic loci for plasma lipids: the Jackson Heart Study.

Publications

Fine-mapping in African Americans of 8 recently discovered genetic loci for plasma lipids: the Jackson Heart Study.

Similar Datasets

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