MAPT and Schnyder corneal dystrophy: There were no between-group differences in plasma Aβ42, Aβ40, Aβ42/Aβ40 ratio, total tau, NfL, and GFAP, only that plasma p-Tau181 was lower in SCD than NC group (3.76 ± 0.55 vs. 4.11 ± 0.45 pg/ml, p = 0.019).