Similar lysosomal abnormalities in cortex of patients with sporadic FTLD‐TDP type A and patients with FTD‐GRN

Loss‐of‐function mutations in progranulin (GRN) are an autosomal dominant cause of frontotemporal dementia (FTD). Progranulin is critical for maintenance of lysosomal function. Patients with FTD due to GRN mutations (FTD‐GRN) exhibit signs of lysosomal dysfunction, which may contribute to FTD‐GRN pathogenesis. To assess the potential involvement of lysosomal dysfunction in FTD of sporadic origin, we investigated whether the lysosomal abnormalities of FTD‐GRN are also present in patients with sporadic frontotemporal lobar degeneration with TDP‐43 pathology (FTLD‐TDP) type A, the same FTLD subtype found in patients with FTD‐GRN.