[1] Univ Oxford, Wellcome Trust Ctr Human Genet, Oxford OX1 2JD, England
[2] Univ Oxford, Oxford Ctr Diabet Endocrinol & Metab, Oxford OX1 2JD, England
[3] Wellcome Trust Sanger Inst, Cambridge, England
[4] Inst Pasteur, F-59019 Lille, France
[5] Univ London Imperial Coll Sci & Technol, London, England