1. Division of Metabolism; University Children's Hospital; Zurich Switzerland
2. Children's Research Center; Zurich Switzerland
3. Pediatric Endocrinology; Departments of Pediatrics and Clinical Research; University of Bern; Bern Switzerland
4. University Institute of Clinical Chemistry; University Children's Hospital; University of Bern; Bern 3010 Switzerland
5. Department of Molecular and Human Genetics; Baylor College of Medicine; Houston Texas 77030