Interestingly, perturbation of several histone methyltransferases, such as nuclear receptor binding SET domain protein 1 (NSD1) for histone H3 lysine 36 (H3K36) and mixed lineage leukemia 2 (MLL2) for histone H3 lysine 4 (H3K4), causes Sotos syndrome and Kabuki syndrome, respectively, both of which show intellectual disability [1, 2]. Here, NSD1 is linked to Kabuki syndrome.