MAPT and Alzheimer disease: We also tested the associations between CSF PGRN and each of the core CSF biomarkers of AD (T‐tau, P‐tau181P and Aβ1–42) in linear regression models for both ADAD (DIAN) and late‐onset AD (ADNI) (Figs 6C–H and 7D–L; Appendix Table S8 summarizes the results including biomarker outliers).