1. Department of Medicine, University of California, Los Angeles, California.
2. Department of Molecular and Medical Pharmacology, University of California, Los Angeles, California.
3. Department of Chemistry and Biochemistry, University of California, Los Angeles, California.
4. Department of Human Genetics, University of California, Los Angeles, California.
5. Division of Epidemiology, Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, Texas.