NRGN and Alzheimer disease: In recent years, several non-amyloid and non-tau -related candidates have been proposed, these including the synaptic protein neurogranin that seems specific for AD and to predict future rate of cognitive deterioration (Thorsell et al., 2010; Blennow, 2017), TDP-43, a marker of protein aggregates which is correlated with clinical and neuropathology features indexes of MCI and AD patients (Tremblay et al., 2011) and neurofilament light chain, a marker of neurodegeneration (Mattsson et al., 2017; Gaetani et al., 2019; Zetterberg and Blennow, 2021), amongst others.