It is noteworthy that familial and sporadic cases of tauopathies share many clinical phenotypes: for instance, Frontotemporal dementia and parkinsonism linked to chromosome 17 (FTDP-17), a familial form of FTLD initially associated with MAPT mutations [275], was later shown to affect also patients with mutations in the nearby gene progranulin, although they are not clearly distinguishable from FTLD-tau patients [275]. This evidence concerns the gene MAPT and Parkinson disease.