SYNGAP1 and Down syndrome: As regards SynGAP1, human mutations are known to cause the SynGAP syndrome, which is characterized by developmental delay and intellectual disability (Kilinc et al., 2018; Holder et al., 2019; Gamache et al., 2020), and mice lacking SynGAP1 exhibit mislocalization of AMPARs (Vazquez et al., 2004; Muhia et al., 2012).