To investigate whether DYRK1A conversely promotes APC proliferation and whether it acts independently in DS pathophysiology or cooperates with other molecules synergistically, we prepared several genome-edited Tri21 iPSC lines, in which DYRK1A was targeted in one or two chromosomes in the XIST-Tri21 iPSC line (DY+/+/m- and DY+/m/m-XIST-Tri21 iPSC, respectively; Fig. 5a). Here, DYRK1A is linked to Dravet syndrome.