1. Department of Neurosurgery, Keck School of Medicine of the University of Southern California , Los Angeles, California , USA
2. Center for Genetic Epidemiology, Norris Comprehensive Cancer Center, University of Southern California , Los Angeles, California , USA
3. Department of Chronic Disease Epidemiology, Yale School of Public Health , New Haven, Connecticut , USA
4. Department of Epidemiology, School of Public Health, University of California, Berkeley , California , USA
5. Department of Internal Medicine, Yale School of Medicine , New Haven, Connecticut , USA