APOE ε4 carriers with SCD also show higher tau and higher amyloid deposition, defining features of AD (Risacher et al., 2016); reduced gray matter volume in temporal, parietal, and frontal areas (Lee et al., 2016); and reduced whole-brain white matter volume (Dauphinot et al., 2020). This evidence concerns the gene APOE and Schnyder corneal dystrophy.