The aim of the study was to perform a clinical validation of the N-224 tau assay in a multicentre study with two independent cohorts, one including SCD and probable AD (cohort 1) and one including cognitively healthy controls, SCD, mild cognitive impairment (MCI), and patients with AD and non-AD dementias (cohort 2). This evidence concerns the gene MAPT and Schnyder corneal dystrophy.