Participants with AD dementia were significantly older (p = .015), carried the APOE ε4 allele at significantly higher rates (p < .001), and scored significantly worse on MMSE (p = .022), ROCF-R (p = .006), ROCF-C (p = .014), LOG-I (p = .025), and LOG-D (p < .001) compared to FTLD dementia participants. This evidence concerns the gene APOE and dementia.