GRM2 and schizophrenia: Taken together, these observations suggest that the epigenetic hypothesis of schizophrenia is supported by the following evidence obtained in postmortem human brain: (i) alterations of glutamic acid decarboxylase 67 (gene symbol = GAD1), DNMT and reelin in GABAergic neurons, and (ii) of brain derived nerve growth factor (BDNF), vesicular glutamate transporter (VGLUT1) and (iii) alterations in mGlu2/3 receptors in glutamatergic neurons (Guidotti et al., 2011; Nicoletti et al., 2011).