[1] Hop Necker Enfants Malad, Paris, France
[2] Erasmus MC, Rotterdam, Netherlands
[3] Univ Amsterdam, Acad Med Ctr, NL-1105 AZ Amsterdam, Netherlands
[4] HagaZiekenhuis, The Hague, Netherlands
[5] Ctr Hosp Henri Mondor, Creteil, France
[6] Univ London St Bartholomews Hosp Med Coll, Queen Marys Sch Med, London, England
[7] Amgen Inc, Thousand Oaks, CA 91320 USA
[8] Hosp Claude Huriez, Lille, France
[9] Amgen LTD, Cambridge, England