In a study focused on the relation of NMDAR interacting PSD proteins with bipolar disorder, major depression, and schizophrenia, a decreased expression of SAP102 was observed in all three psychiatric disorders, suggesting that a lack of SAP102 is linked to the development of mental illnesses (Kristiansen and Meador-Woodruff, 2005). The gene discussed is DLG3; the disease is schizophrenia.