Sequence analysis of tau in familial and sporadic progressive supranuclear palsy.

Progressive supranuclear palsy (PSP) is a tau deposition neurodegenerative disorder which usually occurs in sporadic form and is associated with a common variant of the tau gene. Rare familial forms of PSP have been described. Recently familial frontotemporal dementia linked to chromosome 17 (FTDP-17) has been shown to be due to mutations in tau and there may be a clinical and pathological overlap between PSP and FTDP-17. In this study we have analysed the tau sequence in two small families with PSP, and a number of clinically typical and atypical sporadic cases with pathological confirmation of the diagnosis. The tau mutations described in FTDP-17 were not found in the most clinically diagnosed patients with PSP. This suggests that usually FTDP-17 and PSP, including the rare familial form of PSP, are likely to be separate conditions and that usually PSP and typical PSP-like syndromes are not due to mutations in tau.