Dysfunction of GluN3A due to failure of downregulation or aberrant reactivation beyond the physiological time window is implicated in multiple neurological diseases, such as Huntington’s disease (Marco et al., 2013; Wesseling and Perez-Otano, 2015; Mahfooz et al., 2016; Marco et al., 2018), addiction (Yuan and Bellone, 2013; Yuan et al., 2013; Jin et al., 2014), and schizophrenia (Glantz and Lewis, 2000; Mueller and Meador-Woodruff, 2004; Takata et al., 2013). The gene discussed is GRIN3A; the disease is juvenile Huntington disease.