NSD1 and Luscan-Lumish syndrome: Trans-heterozygote models of DNMT3A and NSD1 would be useful to better understand both TBRS and SS, and the development of other related trans-heterozygote models would also be warranted [i.e. NSD1 and SET domain containing 2 (SETD2), which cause SS and Luscan-Lumish syndrome, respectively] (Pappas and Rabin, 2022).