MAPT and Alzheimer disease: In PD brains, there were no p-tau-immunoreactive neurons throughout the midbrain or SN, except for two cases that had AD co-pathology (LBD-1 and LBD-7) and another case with primary ageing-related tauopathy (PART, LBD-3; Table 1).3 The mean area of p-tau load detected in PSP was 22.52% ± 9.54, and the mean area of pathological-α-synuclein load in PD was 12.56% ± 5.90.