(Research Project 1) The overall objective of the proposed study is to identify novel genes and functional genetic variants associated with blood pressure (BP) at 9 loci which attained genome-wide significance in the recent Asian Genetic Epidemiology Network (AGEN)-BP genome-wide association study (GWAS) meta-analysis using next generation sequencing technology. The proposed study will be carried out among 5,000 Han Chinese participants of the International Collaborative Study of Cardiovascular Disease in Asia (InterASIA). InterASIA provides an extraordinary resource on BP-related phenotypes as well as sufficient quantities of DNA already stored at our laboratories for genetic research. In the proposed study, we will discover novel functional variants by deep sequencing contiguous genomic regions of 9 GWAS-implicated loci among 300 InterASIA participants with the highest mean arterial pressure (MAP) and 300 participants not taking antihypertension medication with the lowest MAP. This agnostic sequencing approach will allow us to examine intergenic variants with potentially important but not well-understood regulatory functions as well as all 15 known genes at these loci, which span an average of 155 kilobases each. Bioinformatic tools will be used to filter the large number of discovered variants, prioritizing those with predicted functional relevance. To maximize statistical power, rare variants will be grouped using: 1) an agnostic sliding window approach which aggregates rare variants in adjacent and overlapping segments across the entire loci; and 2) a biology-based approach which aggregates rare variants by known functional units (e.g. conserved region or gene). We will use state-of-the-art statistical methods to examine the collective effects of rare variants in aggregate analyses. Novel low-frequency and common variants will be examined separately using traditional single-marker analyses. We will genotype the 200 most promising novel variants among the remaining 4,400 InterASIA participants and test the association between each variant and BP among the 5,000 (4,400 genotyped + 600 sequenced) InterASIA participants. We will replicate each of the 25 most promising variants in an independent random sample of 10,000 Han Chinese participants. In addition, we will leverage existing GWAS, whole-exome, and phenotype data available in the database of Genotypes and Phenotypes to assess the trans-ethnic relevance of the 25 most promising BP variants within large, population-based samples of up to 15,076 African-American and 30,821 European- American participants. Ancestry-specific and overall meta-analyses will then be carried out. These findings may have important clinical and public health implications. By helping to elucidate the biological pathways underlying BP regulation, these findings may be used to develop novel gene-based strategies for the prevention and treatment of hypertension. Furthermore, the experience gained by the proposed COBRE junior faculty investigator should serve as an important stepping stone to her success as an independent researcher.
(Research Project 1) The proposed study will identify novel functional genetic variants associated with blood pressure (BP) by deep sequencing genomic regions implicated in a recent BP genome-wide association study meta-analysis among participants of the International Collaborative Study of Cardiovascular Disease in Asia. With replication of promising variants in a large sample of Han Chinese and assessment of their trans-ethnic relevance in large population based samples of African- and European-American participants, the findings from the proposed study promise to provide timely, undiscovered and important insights into the genetic mechanisms underlying blood pressure regulation. These findings may have important clinical and public health implications, leading to the development of novel gene-based strategies for the prevention and treatment of hypertension.
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