APOE and Mental deterioration: As we noted above, larger GWASs of Alzheimer’s disease will produce summary data with more signals from non-APOE-e4-linked variants, and these should be tested for their association with normal-range cognitive ability and cognitive decline at different thresholds; we note that a previous study [66] found no relation between a PGS calculated from an older Alzheimer’s GWAS and cognitive abilities in this same sample (see also ref. [67] for an example of a combination of APOE and PGS variables).