The Schizophrenia Working Group of the Psychiatric Genomics Consortium (PGC) genome-wide association study (GWAS) 2 highlighted associations between genetic variation in glutamate genes and schizophrenia, specifically, single-nucleotide polymorphisms (SNPs) in GRM3 (metabotropic glutamate receptor 3), GRIN2A (N-methyl-d-aspartate [NMDA] type subunit GluN2A), SRR (serine racemase), GRIA1 (GluA1 subunit of α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid [AMPA] receptor), and GPM6A (glycoprotein M6A), among which GRM3 rs12704290 is one of the top hits12. Here, SRR is linked to schizophrenia.