APOE and Parkinson disease: When we analyzed LBD and PD subjects together, we found a trend toward higher levels of Δtau314 in APOE ε4 carriers (8.667; 4.064 - 11.63 ng/g; n = 7) relative to non-carriers (3.376; 1.988–7.265 ng/g; n = 26) (Fig. 3c), and an ~ 4-fold higher Δtau314: T-tau ratio in APOE ε4 carriers (0.2751; 0.1178–0.7082) compared to non-carriers (0.0726; 0.02375–0.1328) (Fig. 3d).