1. Department of Neurosurgery (A)PEV, CJJA), University Hospital Rotterdam, Section Group Gene Therapy (MdCE, DV, AB), Department of Medical Biochemistry, University of Leiden, Department of Neuro-oncology (CV, PSS), Daniel den Hoed Clinic Rotterdam, IntroGene BV (DWvB, DV, PMH, AB), Rijswijk, Department of Pediatrics (PMH), University Hospital Rotterdam, Rotterdam, The Netherlands