Taken together, these results have both diagnostic and pathogenesis/therapeutic implications: (1) proNGF (and possibly, NGF and/or their ratio) may provide additional and independent biological information compared to the other biomarkers, providing a further diagnostic accuracy; (2) more globally, these results suggest that a dysmetabolism in the NGF system could be present in FTD and possibly play a role in FTD pathogenesis, as it has been proposed for AD (Capsoni et al., 2011; Tiveron et al., 2013; Pentz et al., 2020). This evidence concerns the gene NGF and Alzheimer disease.