H2BC21 and Alzheimer disease: Although we could not rule out the possible effects of p300/CBP activation on other non‐histone targets, our current data corroborate earlier reports that CSP‐TTK21‐mediated H2B acetylation is associated with upregulation of plasticity genes in normal and AD‐like conditions (Chatterjee et al., 2013; Chatterjee et al., 2018).