GRN and frontotemporal dementia: While microglia have been implicated in TDP-43 pathology in progranulin-deficient FTLD-TDP (GRN-FTD),17 most attention to TDP-43-linked splicing effects has focused on neuronal cells and, more specifically, on neuronal cells with TDP-43 pathology.12,18TARDBP is broadly expressed across multiple brain cell types in human and mouse.19–21 These observations raise several fundamental questions: (1) does TDP-43 dysregulation affect splicing outcomes similarly or distinctly across cell types and (2) do they occur independently of disease-associated gene expression changes?