AK2 and frontotemporal dementia: Within the 400 CSF features, 18 analytes were specific to AD (such as GDA, PDE6D, FN1), seven to PD (SEMA4B, TNFSF8), and three to FTD (VSIG2, GLIPR1, IGFBP4), whereas 147 (AK2, EIF3G, MDH1) were shared by all diseases (Fig. 2C&E).