NSD2 and microcephaly: In humans, NSD2 is located in a critical region of microdeletion 4p16.3 which is associated with Wolf-Hirschhorn syndrome (Bergemann et al., 2005), which presents with microcephaly at birth (Bernardini et al., 2018; Zanoni et al., 2021), global developmental delay, postnatal growth deficiency, ID, distinct craniofacial features, and seizures (Kagitani-Shimono et al., 2005; Battaglia et al., 2021; Wiel et al., 2022).