Moreover, we experimentally confirmed that two frameshift deletion mutations (GRIK1p.Phe24fs and GRIK1p.Thr882fs) and one nonsense mutation (GRIK2p.Arg300Ter) identified in patients with schizophrenia weaken or even disrupt the interaction between GRIK and PSD95 proteins. Here, DLG4 is linked to schizophrenia.