Like clusterin and other secreted chaperones (Chaplot et al., 2020), TTR colocalizes with Aβ in human AD plaques, further indicating its possible role as an extracellular chaperone (Buxbaum and Johansson, 2017; Cao et al., 2020; Ciccone et al., 2020). This evidence concerns the gene TTR and Alzheimer disease.