C‐terminal Ng peptides that are detectable by an in‐house ELISA but that do not bind to NG‐H6 constituted on average about 50% of all Ng in the 20 CSF samples studied, and no group differences in the ratio of C‐terminal fragments to total‐Ng among control and AD samples could be detected. The gene discussed is NRGN; the disease is Alzheimer disease.