[1] Univ Childrens Hosp, Dept Gen Pediat, D-40225 Dusseldorf, Germany
[2] Univ Medi Ctr Hamburg Eppendorf, Dept Pediat Nephrol, D-20246 Hamburg, Germany
[3] Univ Hosp Bonn, Inst Human Genet, D-53127 Bonn, Germany
[4] Tech Univ Munich, Dept Human Biol, D-85350 Freising Weihenstephan, Germany
[5] Univ Hosp Mannheim, Dept Pediat, D-68167 Mannheim, Germany