To test this hypothesis, we retrieved and re‐analyzed hippocampal RNA‐seq data from mutant mice that lack the H3K4 methyltransferases Kmt2a or Kmt2b from hippocampal neurons of the adult brain and also display hippocampus‐dependent memory impairment (Kerimoglu et al, 2013; Kerimoglu et al, 2017). The gene discussed is KMT2B; the disease is memory impairment.