Using immunohistochemistry, we detected significant Aβ and tau staining in the SCN, hippocampus and retina in ApoE−/− but not C57BL/6J mice (Fig. 3a,b, Supplementary Fig. 2), providing proof that ApoE−/− mice developed neurodegeneration at a young age and thus represented an adequate model for AD. This evidence concerns the gene APOE and Alzheimer disease.