APOE and Schnyder corneal dystrophy: Though still limited, a Subjective Cognitive Impairment Cohort (SCIENCe) study has found that the SCD-plus criteria age ≥ 60 and APOE ε4 carriership were associated with an increased risk of preclinical AD, which is defined by amyloid positivity on either PET or cerebrospinal fluid (CSF) (Slot et al. 2018).