MDH1 and frontotemporal dementia: By comparing the 26 proteins that were upregulated in both the secretome of GRN ko hiMGL and in the CSF of FTD-GRN patients (Fig. 3B and Appendix Table S2) we identified six proteins, which we refer to as panel 6, including fatty acid binding protein 3 (FABP3), malate dehydrogenase 1 (MDH1), GDP dissociation inhibitor-1 (GDI1), macrophage-capping protein (CAPG), CD44, and glycoprotein NMB (GPNMB) (Figs. 3A–C and 4A).