Though astrocytes express low levels of progranulin in vivo (Kaplelach et al. 2023; Petkau et al. 2010), astrocytes become reactive and may lose homeostatic function in degenerated brain regions of patients with FTD due to GRN mutations (Gerrits et al. 2022; Marsan et al. 2023). Here, GRN is linked to frontotemporal dementia.