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GhostKnockoff Inference Empowers Identification of Putative Causal Variants in Genome-wide Association Studies

Abstract

Recent advances in genome sequencing and imputation technologies provide an exciting opportunity to comprehensively study the contribution of genetic variants to complex phenotypes. However, our ability to translate genetic discoveries into mechanistic insights remains limited at this point. In this paper, we propose an efficient knockoff-based method, GhostKnockoff, for genome-wide association studies (GWAS) that leads to improved power and ability to prioritize putative causal variants relative to conventional GWAS approaches. The method requires only Z-scores from conventional GWAS and hence can be easily applied to enhance existing and future studies. The method can also be applied to meta-analysis of multiple GWAS allowing for arbitrary sample overlap. We demonstrate its performance using empirical simulations and two applications: (1) a meta-analysis for Alzheimer's disease comprising nine overlapping large-scale GWAS, whole-exome and whole-genome sequencing studies and (2) analysis of 1403 binary phenotypes from the UK Biobank data in 408,961 samples of European ancestry. Our results demonstrate that GhostKnockoff can identify putatively functional variants with weaker statistical effects that are missed by conventional association tests.

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References
1.
Chen C, Pollack S, Hunter D, Hirschhorn J, Kraft P, Price A . Improved ancestry inference using weights from external reference panels. Bioinformatics. 2013; 29(11):1399-406. PMC: 3661048. DOI: 10.1093/bioinformatics/btt144. View

2.
Lin D, Sullivan P . Meta-analysis of genome-wide association studies with overlapping subjects. Am J Hum Genet. 2009; 85(6):862-72. PMC: 2790578. DOI: 10.1016/j.ajhg.2009.11.001. View

3.
Schaid D, Chen W, Larson N . From genome-wide associations to candidate causal variants by statistical fine-mapping. Nat Rev Genet. 2018; 19(8):491-504. PMC: 6050137. DOI: 10.1038/s41576-018-0016-z. View

4.
Yang H, Chen R, Wang Q, Wei Q, Ji Y, Zheng G . De novo pattern discovery enables robust assessment of functional consequences of non-coding variants. Bioinformatics. 2018; 35(9):1453-1460. PMC: 6499232. DOI: 10.1093/bioinformatics/bty826. View

5.
Leung Y, Valladares O, Chou Y, Lin H, Kuzma A, Cantwell L . VCPA: genomic variant calling pipeline and data management tool for Alzheimer's Disease Sequencing Project. Bioinformatics. 2018; 35(10):1768-1770. PMC: 6513159. DOI: 10.1093/bioinformatics/bty894. View