We further established various types of systematically designed partial trisomy 21 iPSCs (Partial-Tri21 iPSCs), leading to the identification of two responsible genes, namely dual-specificity tyrosine-phosphorylation-regulated kinase 1A (DYRK1A) and phosphatidylinositol glycan anchor biosynthesis, class P (PIGP). Here, DYRK1A is linked to trisomy 21.