Single nucleotide polymorphisms or abnormal expression of NTNG1 and NTNG2 are related to psychiatric disorders such as autism, Rett syndrome, schizophrenia, and bipolar disorder in human and murine models (Fukasawa et al., 2004; Aoki-Suzuki et al., 2005; Chuang et al., 2015; Huang and Hsueh, 2015; Heimer et al., 2020). The gene discussed is NTNG2; the disease is bipolar disorder.