1. Center for Epidemiology and Population Health Baylor College of Medicine Houston Texas USA
2. Department of Pediatrics Baylor College of Medicine Houston Texas USA
3. Texas Department of State Health Services Birth Defects Epidemiology and Surveillance Branch Austin Texas USA
4. Department of Epidemiology Human Genetics and Environmental Sciences, University of Texas School of Public Health Austin Texas USA
5. Department of Pediatrics University of Texas Southwestern Medical Center Dallas Texas USA
6. Department of Epidemiology Human Genetics and Environmental Sciences, University of Texas School of Public Health Houston Texas USA