1. Metabolic Research Laboratories (D.B.S., R.K.S., C.A., S.O.), University of Cambridge, Addenbrooke’s Hospital, Cambridge CB2 0QQ, United Kingdom
2. Institute of Metabolic Science, Department of Medicine (M.R.C., P.A.L., G.J.M.A., A.N.C., K.G.C.S.), University of Cambridge, Addenbrooke’s Hospital, Cambridge CB2 0QQ, United Kingdom
3. Department of Medical Biochemistry and Immunology (B.P.M.), School of Medicine, Cardiff University, Cardiff CF10 3AT, United Kingdom
4. Clinical Endocrinology Branch (E.K.C., P.G.), National Institute of Diabetes, Digestive and Kidney Diseases, Bethesda, Maryland 20892-2560
5. Wellcome Trust Clinical Research Facility (P.R.-B., P.R.M.), Addenbrooke’s Hospital, Cambridge CB2 0SP, United Kingdom
6. Medway Maritime Hospital (I.S.), Gillingham, Kent ME7 5NY, United Kingdom
7. Department of Haematological Medicine (G.J.M.), Kings College London, London WC2R 2LS, United Kingdom
8. Cambridge Institute for Medical Research, and Department of Pathology (S.T.), University of Cambridge, Addenbrooke’s Hospital, Cambridge CB2 0QQ, United Kingdom
9. Institute of Normal Human Morphology (I.M., S.C.), University of Ancona, I-60131 Ancona, Italy