CDKN2A and Huntington disease: Importantly, in NSCs derived from additional nonisogenic HD (namely, ND41656 and ND42222) and control (namely, MIN08i‐33114.B and ND42241) iPSC lines, we observed robust increase in p16INK4a expression (Figure S8A,B) and elevated SA‐ß‐galactosidase activity (Figure S8C), validating our results across multiple HD patients.