The SCD and MCI cohorts further differed from ADNI CNs in terms of cognitive performance (ADNI MCI and DELCODE MCI), years of education (ADNI SCD and DELCODE MCI), amyloid status (DELCODE SCD and ADNI MCI), and APOE-ε4 carriership distribution (ADNI MCI and DELCODE MCI). This evidence concerns the gene APOE and Schnyder corneal dystrophy.