Interestingly, HCRT-1 and HCRT-2 are neuroprotective in PD animal models [71], underscoring the potential importance of HCRT → DA neurotransmission in PD, and relevance of DAOxR1&2-KO mice as model of DA-deficiency relevant to PD. The gene discussed is HCRT; the disease is Parkinson disease.