Parkinson’s disease arises from a localized deposit of alpha-synuclein proteins in the substantia nigra, while PSP arises from a non-localized deposit of tau proteins.42,43 PET imaging can differentiate locations of protein deposits, but is ill-suited for routine clinical screening, compared to safer methods like MRI, making these observed mechanical property differences of high clinical value. This evidence concerns the gene MAPT and Parkinson disease.