MAPT and frontotemporal dementia: To determine whether the lysosomal changes observed in patients with FTD-GRN or sporadic FTLD-TDP type A are specifically associated with TDP-opathy or may be more generally associated with neurodegeneration or neuroinflammation, we extended our investigation to include patients with a subtype of FTLD-TDP not associated with GRN mutations (type C) or a subtype of FTLD-tau (Pick’s disease).