1. Dutch Down Syndrome Foundation; Meppel The Netherlands
2. Department of Clinical Genetics, Research Institute Growth and Development (GROW); Maastricht University Medical Center; Maastricht The Netherlands
3. Department of Clinical Genetics; Leiden University Medical Center; Leiden The Netherlands
4. Department of Human Genetics; Radboud University Medical Centre; Nijmegen The Netherlands
5. Department of Genetics; University Medical Centre Utrecht; Utrecht The Netherlands
6. Department of Genetics; University of Groningen, University Medical Centre Groningen; Groningen The Netherlands
7. Department of Clinical Genetics; Erasmus MC; Rotterdam The Netherlands
8. Department of Clinical Genetics; Academic Medical Center; Amsterdam The Netherlands
9. Department of Clinical Genetics; VU University Medical Center; Amsterdam The Netherlands