1. RTI International, Research Triangle Park, North Carolina
2. Division of Genetics and Metabolism, University of North Carolina at Chapel Hill, Chapel Hill
3. Department of Pediatrics, Duke University School of Medicine, Durham, North Carolina
4. Department of Pathology, Duke University School of Medicine, Durham, North Carolina
5. Department of Neurology, University of North Carolina at Chapel Hill, Chapel Hill
6. Division of Pediatric Endocrinology, University of North Carolina at Chapel Hill, Chapel Hill
7. North Carolina State Laboratory of Public Health, Raleigh
8. Now at Division of Newborn and Childhood Screening, Maryland Department of Health, Laboratories Administration, Baltimore