These data strongly support the hypothesis that Hsa21 gene overexpression (e.g., DYRK1A, APP, TIAM1, and ITSN1 gene products) might dysregulate NMDAR expression and/or function, contributing to DS-like pathogenesis in trisomic mice (Siddiqui et al., 2008). Here, DYRK1A is linked to Dravet syndrome.