The close relationship between orexin and neurodegenerative diseases is further evident in Parkinsons’ disease (PD), in which the orexinergic system was found altered in the basal ganglia nuclei, including globus pallidus, subthalamic nucleus, substantia nigra, and striatum, well-established neuronal centres for the motor control (Yasui et al. 2006; Chieffi et al. 2017; Dell et al. 2013). The gene discussed is HCRT; the disease is neurodegenerative disease.