DTNBP1 (dysbindin) gene variants modulate prefrontal brain function in schizophrenic patients--support for the glutamate hypothesis of schizophrenias.

Dysbindin (DTNBP1) is a recently characterized protein that seems to be involved in the modulation of glutamatergic neurotransmission in the human brain, thereby influencing prefrontal cortex function and associated cognitive processes. While association, neuroanatomical and cellular studies indicate that DTNBP1 might be one of several susceptibility genes for schizophrenia, the effect of dysbindin on prefrontal brain function at an underlying neurophysiological level has not yet been explored for these patients. The NoGo-anteriorization (NGA) is a topographical event-related potential measure, which has been established as a valid neurophysiological marker of prefrontal brain function. In the present study, we investigated the influence of seven dysbindin gene variants on the NGA in a group of 44 schizophrenic patients. In line with our a priori hypothesis, one DTNBP1 polymorphism previously linked to schizophrenia (rs2619528) was found to be associated with changes in the NGA; however, the direction of this association directly contrasts with our previous findings in a healthy control sample. This differential impact of DTNBP1 gene variation on prefrontal functioning in schizophrenic patients vs. healthy controls is discussed in terms of abnormal glutamatergic baseline levels in patients suffering from schizophrenic illnesses. This is the first report on a role of DTNBP1 gene variation for prefrontal functioning at a basic neurophysiological level in schizophrenic patients. An impact on fundamental processes of cognitive response control may be one mechanism by which DTNBP1 gene variants via glutamatergic transmission contribute to the pathophysiology underlying schizophrenic illnesses.