2018). Increased Fe was observed in the brain‐damaged area of AD patients (Maher 2018), which had a significant correlation with Aβ plaque and Tau pathology (van Duijn et al. 2017). Ferritin is a protein that stores and regulates Fe. It is related to AD. Elevated plasma and CSF ferritin levels are a feature of preclinical AD (Goozee et al. 2018). Elevated ferritin levels suggest elevated Fe levels in CSF and brain, which may be related to ferroptosis, which is a cell death pathway caused by lipid peroxide (Acevedo et al. 2019). This evidence concerns the gene MAPT and Alzheimer disease.