Duke Center for Statistical Genetics and Genomics, Duke University, Durham, NC, USA.|Center for Genomic and Computational Biology, Duke University Medical School, Durham, NC, USA.|Center for Genomic and Computational Biology, Duke University Medical School, Durham, NC, USA.|Department of Biostatistics, Yale University, New Haven, CT, USA.|Masters Program in Biostatistics, Department of Biostatistics and Bioinformatics, Duke University Medical School, Durham, NC, USA.|University Program in Genetics and Genomics, Duke University, Durham, NC, USA.|Center for Genomic and Computational Biology, Duke University Medical School, Durham, NC, USA.|University Program in Genetics and Genomics, Duke University, Durham, NC, USA.|Division of Endocrinology, Metabolism & Molecular Medicine, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA.|Division of Biostatistics, Department of Preventive Medicine, Northwestern University Feinberg School of Medicine,Chicago, Illinois, USA.|Division of Endocrinology, Metabolism & Molecular Medicine, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA.|Duke Center for Statistical Genetics and Genomics, Duke University, Durham, NC, USA.|Duke Center for Statistical Genetics and Genomics, Duke University, Durham, NC, USA.