**5. Acknowledgment**

We are grateful to the patients for their cooperation. We further acknowledge the contribution of personnel of the VIB Genetic Service Facility (www.vibgeneticservicefacility.be). This research of the authors was in part funded by the Special Research Fund of the University of Antwerp, the Research Foundation Flanders (FWO-F), the Institute for Science and Technology - Flanders (IWT-F), the Methusalem excellence grant of the Flemish Government, the Interuniversity Attraction Poles program (IUAP) P6/43 of the Belgian Science Policy Office, the Stichting Alzheimer Onderzoek (SAO-FRMA). I.G. is holding a postdoctoral fellowship of FWO-F.
