Association analysis for NMDA receptor subunit 2B (GRIN2B) genetic variants and psychopathology and clozapine response in schizophrenia.

It is known that a syndrome resembling schizophrenia is produced by the N-methyl-d-aspartate receptor antagonists. It has also been demonstrated that the level of an ionotropic N-methyl-d-aspartate 2B subunit (GRIN2B) of the glutamate receptor tends to increase after subchronic administration of clozapine, suggesting that GRIN2B may play an active role in the pathogenesis of schizophrenia and the function of clozapine medication. We studied 100 schizophrenic patients, investigating the associations for the GRIN2B genetic variants, and psychiatric symptoms and clozapine response. No significant differences were demonstrated comparing these three groups in terms of the baseline Brief Psychiatric Rating Scale (BPRS) score (P = 0.441). The percentage of patients scoring within 20% of baseline BPRS after clozapine treatment was similar for the three genotype groups (P = 0.132). A marginally higher mean clozapine dosage was revealed, however, for patients bearing the 2664C/C genotype (P = 0.013). Although replication of this research is required to confirm the results, an association for the GRIN2B C2664T polymorphism and clozapine treatment is suggested from our findings, which may assist in the prediction of optimal dosage for schizophrenic patients.