MERTK and frontotemporal dementia: Unlike the decrease in MERTK observed in the CSF of symptomatic GRN-FTD patients (Fig. 6C) and human-induced microglia (Supplementary Fig. 4A, B), MERTK levels in post-mortem brain tissue did not differ between GRN-FTD patients and non-carrier controls (Supplementary Fig. 4D, E).