SLC17A7 and frontotemporal dementia: As in FTD patients, CatD protein exhibited a heavily neuronal localization (Fig. 4d), and in situ hybridization revealed an increase in Ctsd mRNA expression in excitatory (Slc17a7 +) neurons with no change in expression in local fast-spiking (Pvalb +) interneurons (Fig. 4e–g).