For example, the CSF Aβ42/40 ratio was an important predictor of CSF p‐tau181 levels in both CU (median VIM [95% confidence intervals]; BioFINDER‐2: 1.23 [1.18–1.32], rank #2; ADNI: 1.35 [1.25–1.51], rank #1) and MCI/dementia (BioFINDER‐2: 1.43 [1.32–1.59], rank #1; ADNI: 1.21 [1.10, 1.39], rank #1) groups, while for tau PET it was a more important predictor in the CU group (BioFINDER‐2: 0.67 [0.57–0.80], rank #3; ADNI: 0.91 [0.75–1.05], rank #1) than in MCI/dementia (BioFINDER‐2: 0.86 [0.72–1.06], rank #9; ADNI: 0.75 [0.67–0.83], rank #4). This evidence concerns the gene MAPT and dementia.