Our objective was to investigate the relationships between CSF Aβ42, tau, P-tau, and hypocretin-1 in a large population of patients with cognitive abnormalities, including patients at early and advanced stages of AD, patients affected with other dementias, and hypocretin-deficient patients with narcolepsy-cataplexy (NC). The gene discussed is MAPT; the disease is narcolepsy-cataplexy syndrome.