The ICSD-3 indicate a Narcolepsy type 1 (NT1) diagnosis if one or both of the following are present: (1) cataplexy and a mean sleep latency ≤8 min and two or more sleep-onset REM periods on a Multiple Sleep Latency Test; (2) the cerebrospinal fluid (CSF) hypocretin-1 concentration is either ≤110 pg/or <1/3 of the mean value obtained in normal individuals with the same standardised assay. The gene discussed is HCRT; the disease is Cataplexy.