DAO and bipolar disorder: In mice, G72 has been found to be overexpressed in testis and cerebral cortex, with low to no expression in other tissues [35]. DAOA, which has typically been associated with bipolar disorder (BD) and schizophrenia (SZ), encodes a protein that may act as an activator of the DOA (D-amino acid oxidase) enzyme, which degrades the gliotransmitter D-serine, a potent activator of N-methyl-D-aspartate (NMDA) type glutamate receptors [36].