[1] Ghent Univ Hosp, Dept Pediat Nephrol & Rheumatol, Ghent, Belgium
[2] Great Ormond St Hosp London, Renal Unit, London, England
[3] Hosp Civils Lyon, Lyon, France
[4] Univ Childrens Hosp Heidelberg, Heidelberg, Germany
[5] Univ Ghent, Biostat Unit, Ghent, Belgium
[6] Hannover Med Sch, Dept Pediat Kidney Liver & Metab Dis, Hannover, Germany