1. Biochemical Genetics Laboratory, Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN 55905, USA
2. Illinois Department of Public Health, Chicago, IL 60612, USA
3. Missouri State Public Health Laboratory, Jefferson City, MO 65101, USA
4. Tennessee Department of Health, Division of Laboratory Services, Nashville, TN 37243, USA
5. Pennsylvania Department of Health, Harrisburg, PA 17120, USA
6. Department of Pediatrics, Duke University Medical Center, Durham, NC 27705, USA
7. Newborn Screening Program, Wadsworth Center, New York State Department of Health, Albany, NY 12208, USA