1. Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Churchill Hospital, Oxford, OX3 7LJ, UK.
2. The Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford, OX37BN, UK.
3. Genetics of Complex Traits, Institute of Biomedical and Clinical Science, Peninsula Medical School, Magdalen Road, Exeter EX1 2LU, UK.
4. Diabetes Genetics Group, Institute of Biomedical and Clinical Science, Peninsula Medical School, Barrack Road, Exeter EX2 5DW, UK.
5. Medical Research Council Centre for Causal Analyses in Translational Epidemiology, Bristol University, Canynge Hall, Whiteladies Rd, Bristol, BS2 8PR, UK.