However, total sleep time in untreated narcoleptic patients as well as in mouse models of narcolepsy does not differ from controls over the 24-h period (Dantz et al., 1994; Hara et al., 2001; Tabuchi et al., 2014), a phenotype that is distinct from the lethargy observed after LH lesions or acute LH neuronal inhibition. Here, PLOD1 is linked to narcolepsy.