We then compared its aggregation behaviour with that of a single point deletion mutant (ΔK280), one of the tau mutations found in frontotemporal dementia and parkinsonism linked to chromosome 17 (FTDP-17)19, 20, and a single point mutation mutant (P301L) that is the most common mutation associated with FTDP-17 (ref. 21). Here, MAPT is linked to semantic dementia.