Results from a genome-wide association study (GWAS) have revealed significant associations between narcolepsy and single nucleotide polymorphisms (SNP) located in the T-cell receptor α-locus and P2RY11[14], [15]. Recently, we also conducted a GWAS and identified a novel narcolepsy-related SNP (rs5770917), located adjacent to the gene encoding carnitine palmitoyltransferase 1B (CPT1B) [16]. The mRNA expression levels of CPT1B were associated with this SNP and the expression levels were decreased according to the number of risk alleles (C) [16], [17]. The gene discussed is CPT1B; the disease is narcolepsy.