Circulating blood cell counts represent important intermediate phenotypes for a variety of cardiovascular, pulmonary, hematologic, and immunologic diseases. These traits differ by ethnicity and studying the genetics of these quantitative blood traits in African Americans (AAs) may reveal new biologic pathways that ultimately contribute to our understanding both of biology of blood cell production and of the relationship of blood counts with CVD and other chronic diseases that disproportionately impact AAs. Genome-wide association studies (GWAS), to date, performed mainly in European Americans, have implicated a number of genomic loci. Despite these successes, association signals for blood cell traits are often associated with uncertain effects on gene function or regulation, and therefore not readily translatable to clinical practice or treatment. Several recent advancements hold promise for translating genetic association findings for blood cell traits into mechanism-based therapeutic approaches for clinical disease. First, genome-wide mapping of blood cell type- and lineage-specific promoter and enhancer elements, transcription factor binding patterns and epigenetic profiling now provide a detailed picture of the cis- and trans- regulatory landscape during hematopoiesis. Second, experimental approaches utilizing genome engineering (RNA- guided CRISPR-Cas9) can characterize critical regulatory elements and functional variants of modest effect that are essential for stage-specific, lineage-restricted effects on gene expression. This proposal will utilize the wealth of newly available genetic data in multiple large AA cohorts, including high-coverage whole genome sequence (WGS) data available on ~3,500 JHS participants and exome array data on ~11,400 participants from the REasons for Geographical And Regional Differences in Stroke (REGARDS), the Jackson Heart (JHS) and Women's Health Initiative (WHI) studies to discover and functionally characterize novel genetic associations. These data will be combined with existing GWAS and exome array data on thousands of additional AAs with measured blood cell traits to form the largest and most comprehensive genetic study of blood cell traits ever conducted in AAs. Our study will use novel and established analytic and experimental approaches, consistent with the goals and directives of this initiative, to identify important genetic variants affecting these important blood-based biomarkers.

Public Health Relevance

Cardiovascular disease (CVD) is the leading killer of African Americans. The proposed work will identify novel genetic risk factors for various blood cell measures that influence CVD risk in African Americans and other populations. The results may lead to improved disease diagnosis and treatment.

National Institute of Health (NIH)
National Heart, Lung, and Blood Institute (NHLBI)
Research Project (R01)
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Cancer, Heart, and Sleep Epidemiology A Study Section (CHSA)
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Qasba, Pankaj
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University of North Carolina Chapel Hill
Schools of Medicine
Chapel Hill
United States
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Hu, Yao; Raffield, Laura M; Polfus, Linda M et al. (2018) A common TCN1 loss-of-function variant is associated with lower vitamin B12 concentration in African Americans. Blood 131:2859-2863
Raffield, Laura M; Zakai, Neil A; Duan, Qing et al. (2017) D-Dimer in African Americans: Whole Genome Sequence Analysis and Relationship to Cardiovascular Disease Risk in the Jackson Heart Study. Arterioscler Thromb Vasc Biol 37:2220-2227