Between the predicted neuropathological subgroups, FTD-TDP group (N = 64) showed lower serum TDP-43 levels compared to the FTD-tau group (N = 27) (241.4 pg/mL vs. 356.9 pg/mL, B = 0.416, 95%CI 0.061–0.771, p = 0.022) when adjusted for age and gender (Table 1, Fig. 1). This evidence concerns the gene MAPT and frontotemporal dementia.