GRIN2B and schizophrenia: On the contrary, the expression of the N-methyl-D-aspartate (NMDA) glutamate receptor GRIN2B, a gene implicated in schizophrenia, is promoted by the interaction between GRIN2B promoter and its enhancer that is located 449 kb away; when SET domain bifurcated 1 (SETDB1)-mediated H3K9me3 is enriched around the TSS and bound by the repression-associated protein heterochromatin protein 1α (HP1α), a repressive chromatin structure is formed, leading to the disruption of enhancer–promoter interaction and subsequently GRIN2B inactivation [103–105].