The latest edition of the International Classification of Sleep Disorders (ICSD-3) has classified narcolepsy into narcolepsy type 1 (NT1) and narcolepsy type 2 (NT2) on the basis of levels of hypocretin, also known as orexin, in cerebrospinal fluid (CSF) [1]. This evidence concerns the gene HCRT and narcolepsy-cataplexy syndrome.