GRN and amyotrophic lateral sclerosis: Phagocytic changes have been reported in GRN−/− microglia (Guan et al., 2020; Lui et al., 2016) and in microglia differentiated from ALS peripheral blood mononuclear cells (PBMCs) when compared with control PBMC-derived microglia (Quek et al., 2022).