We then examined whether the co-aggregation of GlcCer and GCase with tau found in PS19 mice with PGRN reduction is also observed in tau pathologies in anterior hippocampal and middle frontal gyrus sections from 5 AD brains, 4 with moderate AD pathological changes (AH2), and 1 frontotemporal dementia (FTD)-GRN. This evidence concerns the gene GRN and Alzheimer disease.