Taken together with the discoveries of the over-production of 4R-tau, and disequilibrium linkage to the tau gene in PSP patients, it is reasonable to presume that variations in intron 9 or intron 10 could be critical to influencing exon 10 inclusion/exclusion in these patients [71,73-75]. Here, MAPT is linked to supranuclear palsy, progressive, 1.