Department of Biostatistics, Center for Statistical Genetics, University of Michigan, Ann Arbor, MI, USA, Department of Dermatology, University of Michigan, Ann Arbor, MI, USA, and Ann Arbor Veterans Affairs Hospital, Ann Arbor, MI, USA.|Department of Biostatistics, Center for Statistical Genetics, University of Michigan, Ann Arbor, MI, USA, Department of Dermatology, University of Michigan, Ann Arbor, MI, USA, and Ann Arbor Veterans Affairs Hospital, Ann Arbor, MI, USA Department of Biostatistics, Center for Statistical Genetics, University of Michigan, Ann Arbor, MI, USA, Department of Dermatology, University of Michigan, Ann Arbor, MI, USA, and Ann Arbor Veterans Affairs Hospital, Ann Arbor, MI, USA.|Department of Biostatistics, Center for Statistical Genetics, University of Michigan, Ann Arbor, MI, USA, Department of Dermatology, University of Michigan, Ann Arbor, MI, USA, and Ann Arbor Veterans Affairs Hospital, Ann Arbor, MI, USA.