To further discriminate neuroanatomic patterns of AD and PSP disease activity in these mixed cases, we performed 3R/4R and 4R RT-QuIC on regions with distinct tau isoform immunostaining: globus pallidus (high PSP, low AD pathology), hippocampus (low PSP, high AD pathology), and frontal lobe (high PSP, high AD pathology). This evidence concerns the gene MAPT and Alzheimer disease.