1. University of Cambridge Metabolic Research Laboratories (N.S., C.M., M.A., O.R., G.L., M.G., K.C.), Wellcome Trust-Medical Research Council Institute of Metabolic Science, Addenbrooke's Hospital, Cambridge CB2 0QQ, United Kingdom
2. Institute of Endocrine Sciences (I.C., P.B.-P.), University of Milan, 20132 Milan, Italy
3. Department of Clinical Biochemistry (O.B., S.B., D.H.), Addenbrooke's Hospital, Cambridge CB2 2OO, United Kingdom
4. Department of Biochemistry (J.S.), University of Leicester, Leicester LE1 7RH, United Kingdom
5. Departments of Paediatrics (T.B.), Birmingham B15 2TT, United Kingdom
6. Department of Clinical Biochemistry (F.G.), Ealing Hospital, London UB1 3EU, United Kingdom
7. Departments of Endocrinology (M.D.), St Bartholomew's Hospital, London E1 4NS, United Kingdom
8. Department of Clinical Biochemistry (A.O., P.C.), Selly Oak Hospital, Birmingham B29 6JD, United Kingdom
9. Clinical Chemistry (M.B.), Birmingham Childrens Hospital, Birmingham B15 2TT, United Kingdom