1. Avera Genetics, Avera McKennan Hospital & University Health Center, Sioux Falls, SD 57105, USA
2. Avera Cancer Institute, Sioux Falls, SD 57105, USA
3. Fred and Pamela Buffet Cancer Center and Eppley Institute for Research in Cancer at University of Nebraska Medical Center, Omaha, NE 68105, USA
4. Department of Biological Psychology, Netherlands Twin Register, Vrije Universiteit Amsterdam, 1081 BT Amsterdam, The Netherlands