Shared molecular signatures were observed across multiple diseases, including MSMP, NPNT, and CCDC80 in CSF for both PD and DLB, TNFSF12, UCHL1, and FLT1 in CSF for both AD and FTD, and FLII, CCDC50, RNF215 in CSF for both AD and PD. This evidence concerns the gene FLT1 and frontotemporal dementia.