In recent studies, reduced cerebrospinal fluid (CSF) levels or brain expression of VGF, Scg2, CgB, and CgA proteins have been reported in patients with Alzheimer’s disease (AD), with an estimated decrease in CSF VGF levels at a rate of 10.9% per year in a longitudinal study of patients with AD [18–20]. This evidence concerns the gene SCG2 and Alzheimer disease.