Sequencing of the DNA fragments from schizophrenic patients and healthy control group was conducted to search for a polymorphism in the gene subunit GRIN1 (rs11146020) associated with susceptibility to schizophrenia, GRIN2B (rs1806201) associated with the efficacy of neuroleptic and polymorphisms in genes of subunits, which determine NMDA receptor functions—GRIN2A [2304–2306 (AAT)] and GRIN2B—2055–2057 (AAC). This evidence concerns the gene GRIN2A and schizophrenia.