1 Genome Research Division, Human Genetics Department, Radboud University Medical Center Nijmegen and Radboud Institute for Molecular Life Sciences, Nijmegen, Netherlands.
2 Center for Pediatrics and Adolescent Medicine, University Hospital Freiburg, Freiburg University Faculty of Medicine, Freiburg, Germany.
3 Department of Pediatrics, University Hospital of Cologne, Cologne, Germany.
4 Center for Molecular Medicine, University Hospital of Cologne, Cologne, Germany.
5 Nephrology Research Laboratory, Department II of Internal Medicine, University Hospital of Cologne, Cologne, Germany.