BDNF and schizophrenia: Other observations on candidate genes include hyper-methylation of the glutamate receptors GRM2 and GRM5 in the peripheral blood of schizophrenia subjects [125], hyper-methylation of BDNF promoter in the whole blood of patients [126], promoter hyper-methylation of the serotonin receptor 5HTR1A in peripheral leukocytes [127], and hypo-methylation of the serotonin receptor HTR2A promoter in patient saliva [128], which is compatible with the result of the brain study [129].