Interestingly, we found that in non-AD patients, APOE ε4 carriers had lower CSF Aβ42 (p = 0.018) and higher T-tau/Aβ42 ratios (p < 0.001) and P-tau181/Aβ42 ratios (p = 0.002) than non-carriers. Here, MAPT is linked to Alzheimer disease.