Most of the current available quantitative Ng immunoassays [4, 9, 34, 50] contain antibodies recognizing the C-terminal half of Ng (CT-Ng), and herein we confirmed that CT-Ng is a reliable CSF biomarker to discriminate cognitive impairment (AD and MCI-AD) from controls [4, 9]. This evidence concerns the gene NRGN and Cognitive impairment.