MAPT and Alzheimer disease: On the other hand, it is only recently that AD genetic risk factors have been also associated with Tau pathology, following the development of systematic screenings in Drosophila which allowed for the identification of genetic modifiers by assessing eye roughness and eye size as readouts of Tau neurotoxicity [20, 48, 49] and their associations with endophenotypes related to Tau [6, 16, 20].