HTR2A and schizophrenia: In our analyses, we also identified several genes that were differentially methylated by male age including DRD3, SYNGAP1, HTR2A, and GRIN1. Hypermethylation of DRD346 and HTR2A47 has been reported to be significantly associated with the risk of schizophrenia, while hypomethylation of GRIN1 has been linked to depression in children48.