We have shown recently that soluble p‐tau increases may in fact drive tau aggregation and spread across interconnected brain regions (Pichet Binette et al, 2022) therefore, soluble p‐tau increases may be a key link between Aβ deposition and tau aggregation in AD. However, the underlying mechanisms that link Aβ and subsequent increases in soluble p‐tau in CSF or plasma are not well understood. This evidence concerns the gene MAPT and Alzheimer disease.