In a similar manner, normalizing CSF tau368 to t-tau may lead to a better marker of tau aggregates, by correcting for shifting proteolytic processing and secretion of tau, with N- to mid-terminal tau truncated fragments being released into the CSF, and that more C-terminal species containing the aggregation-prone microtubule-binding region are retained in the core of tangles [36], and thus becoming relatively scarcer in AD. Here, MAPT is linked to Alzheimer disease.