title: Detecting rare variant effects using extreme phenotype sampling in sequencing association studies.
abstract: In the increasing number of sequencing studies aimed at identifying rare variants associated with complex traits, the power of the test can be improved by guided sampling procedures. We confirm both analytically and numerically that sampling individuals with extreme phenotypes can enrich the presence of causal rare variants and can therefore lead to an increase in power compared to random sampling. Although application of traditional rare variant association tests to these extreme phenotype samples requires dichotomizing the continuous phenotypes before analysis, the dichotomization procedure can decrease the power by reducing the information in the phenotypes. To avoid this, we propose a novel statistical method based on the optimal Sequence Kernel Association Test that allows us to test for rare variant effects using continuous phenotypes in the analysis of extreme phenotype samples. The increase in power of this method is demonstrated through simulation of a wide range of scenarios as well as in the triglyceride data of the Dallas Heart Study.
authors.affiliation: Department of Biostatistics, Harvard School of Public Health, Boston, MA 02115, USA.
authors.forename: Ian J
authors.initials: IJ
authors.lastname: Barnett
authors.forename: Seunggeun
authors.initials: S
authors.lastname: Lee
authors.forename: Xihong
authors.initials: X
authors.lastname: Lin
mesh_terms: D000091303:Angiopoietin-Like Protein 3; D000075803:Angiopoietin-Like Protein 4; D000075802:Angiopoietin-like Proteins; D042682:Angiopoietins / Q000235:genetics; D056726:Genetic Association Studies; D014644:Genetic Variation; D006801:Humans; D008957:Models, Genetic; D010641:Phenotype; D017422:Sequence Analysis, DNA / Q000379:methods; D014280:Triglycerides / Q000235:genetics
chemical_list: C479896:ANGPTL3 protein, human; C474772:ANGPTL4 protein, human; C473567:ANGPTL5 protein, human; D000091303:Angiopoietin-Like Protein 3; D000075803:Angiopoietin-Like Protein 4; D000075802:Angiopoietin-like Proteins; D042682:Angiopoietins; D014280:Triglycerides