OXTR and schizophrenia: Single-nucleotide polymorphisms (SNPs) of the oxytocin gene, including rs4813625 [107,108], rs3761248 [107], and rs2740204 [107,108], and the oxytocin receptor gene, including rs53576 [109], rs237885, [109], and rs9840864 [110], may contribute to schizophrenia vulnerability.