HTR2A and schizophrenia: HTR2A CpG sites were either hypermethylated (near rs6311, at position −1438 of the promoter region) or hypomethylated (near rs6313, at position 102 of exon I) in the prefrontal cortex of patients with schizophrenia, potentially resulting in downregulation of HTR2A expression in patients with schizophrenia [10].