GRN and frontotemporal dementia: Comparison of lysosomal measures in frontal and occipital cortices of patients with FTD-GRN and sporadic FTLD-TDP type A (Figs. 1, 2, 3, Additional file 1: S1, S2) suggests an association of lysosomal abnormalities with TDP-opathy, neurodegeneration, or inflammation rather than with progranulin haploinsufficiency.