A total of 45 polymorphisms in the genes GRIN1, GRIN2A, GRIN2B, GRIN3A,GRIA1, GRIK2, GRM2, GRM3, GRM5, GRM8, SLC1A1, SLC1A3 and GAD1 were genotypedin 258 patients with schizophrenia. Here, GRIK2 is linked to schizophrenia.