Histone 3 lysine 9 dimethylation (H3K9me2) by G9a/GLP facilitates DNA methylation (Shinkai & Tachibana, 2011) and hypermethylation of various genes implicated in synaptic plasticity and memory, including CREB‐regulated transcription co‐activator 1 (CRTC1) and brain‐derived neurotrophic factor (BDNF), is reported in the human hippocampus in AD (Nagata et al., 2015; Mendioroz et al., 2016). Here, BDNF is linked to Alzheimer disease.