HCRTR2 has been implicated in substance use disorders (K. T. Schmeichel et al., 2015; Aldridge et al., 2022; Chen et al., 2024), and QRFP has been shown to exert neuroprotective effects in AD via heterodimerization of QRFPR with orexin receptors (J. Davies et al., 2015). Here, HCRTR2 is linked to Alzheimer disease.