In addition to these sporadic diseases, FTD and Parkinsonism linked to chromosome 17 (FTDP-17t) is caused by mutations in MAPT—this genetic form representing the cornerstone piece of evidence for the involvement of tau in non-familial disease (Hutton et al., 1998; Spillantini et al., 1998; D’Souza et al., 1999). This evidence concerns the gene MAPT and familial disease.