[1] Free Univ Amsterdam, Dept Oral Cell Biol ACTA, NL-1081 BT Amsterdam, Netherlands
[2] Leiden Univ, Med Ctr, Dept Endocrinol & Metab Dis, Leiden, Netherlands
[3] Leiden Univ, Med Ctr, Dept Pediat, Leiden, Netherlands
[4] Massachusetts Gen Hosp, Endocrine Unit, Boston, MA 02114 USA
[5] Netherlands Inst Dev Biol, Utrecht, Netherlands