Known polymorphisms in MAPT which confer susceptibility not only for AD and FTD, but other neurodegenerative diseases as well, together with a possible additional novel disease locus near the MAPT gene [188], strongly support the key role of tau protein not only in primary tauopathies but also in the pathogenesis of LOAD and other secondary tauopathies. Here, MAPT is linked to frontotemporal dementia.