BDNF and neurodegenerative disease: The DEGs in hTH of the brains of individuals with FTLD-GRN included the upregulated genes implicated in neurodegenerative diseases, such as APP, UBB, and DNAJB1, and many down-regulated synaptic genes, including synaptophysin (SYP), synaptotagmin 1 (SYT1), and GRIN2A; whereas the DEGs in hFCX included upregulated genes, such as MAP1A, synapsin 1 (SYN1), GRIN1, BIN1, UBB, and GABRA5, and down-regulated genes, such as BDNF, DCC, ROBO1, GAP43, NRG1, SYT1, and SYP (Figure 6B and Supplemental Table 3).