MAPT and Alzheimer disease: The lack of association between tau burden and MAPT H1H1 may not be unexpected given that this diplotype prevalence is elevated in PSP and CBD, wherein the underlying tau pathology is a 4-repeat isoform tauopathy and a straight filament, whereas CTE is similar to AD with a mixture of both 3- and 4-repeat and a paired helical filament, and so very different [Woerman et al., 13].