DLGAP3 encodes SAP90/PSD95-associated protein 3, a postsynaptic scaffolding protein highly expressed at glutamatergic synapses in the striatum 1. The protein functions as a molecular adapter linking ion channels to the subsynaptic cytoskeleton and may induce enrichment of PSD-95/SAP90 at the plasma membrane. DLGAP3 plays a critical role in synaptic organization and neuronal signaling within cortical-striatal-thalamic circuits. Mechanistically, DLGAP3 interacts with RGS12 to suppress MAPK/ERK signaling by inhibiting BRAF transcription and translation 2. The protein's regulation involves epigenetic control through histone deacetylases HDAC1/2 and MeCP2 in the dorsal striatum 3. DLGAP3 dysfunction is associated with multiple neuropsychiatric conditions. Knockout mouse models display compulsive grooming behaviors resembling obsessive-compulsive disorder (OCD) 4. Genetic variants show associations with atypical antipsychotic-induced OC symptoms in schizophrenia patients, particularly through interactions with glutamate transporter SLC1A1 5. The gene has been implicated in Tourette syndrome susceptibility 1 and identified as a hub gene in Parkinson's disease expression networks 6. Additionally, DLGAP3 functions as a tumor suppressor in gliomas, where reduced expression correlates with poor patient survival 2.