The colocalised signal of Aβx-34 and BACE2 was seen in three categories of objects (Fig. 4), in all analysed samples: four individual DS-AD brains (Fig. 4a–c), five euploid sporadic AD subjects (example in Supplementary Fig. 8a, for complete list of brain samples see Supplementary Table 1) and (in the fine vesicle compartment only) in five non-demented control euploid subjects’ neurons (age 42–84), as well as DS brain from a 28 yr old with no plaques or dementia, (examples in Fig. 4d, for complete list of brain samples see Supplementary Table 1). This evidence concerns the gene BACE2 and dementia.