NRGN and Alzheimer disease: According to Koen et al., several CSF biomarkers, such as visinin-like protein 1, neurogranin, BACE1, and Aβ1-40, were all correlated negatively with the precuneus gray matter volume, which was linked to the loss of brain structural integrity that occurs during the early stages of AD (Schaeverbeke et al., 2019).