At present it is commonly accepted by the scientific community that the neuroprotective effect of TTR in AD is linked to the following aspects: (1) TTR levels are decreased in the CSF of AD patients [67], (2) overexpressing human TTR wild type (hTTR-wt) in an AD mouse model normalizes cognition and memory [25], and (3) in vitro TTR reduces Aβ fibrillation [52,68,69]. This evidence concerns the gene TTR and Alzheimer disease.