NGF and Alzheimer disease: When FTD and AD samples are stratified based on the presence/non-presence of a detectable NGF peak (see Table 4), we find a significant difference in average proNGF level between the two subpopulations FTD_NGF_1 vs. FTD_NGF_0 (M-W test, p < 0.01) and ADNGF_1 vs. AD_NGF_0 (Mann–Withney test, p < 0.05) (Figure 6A).