Previous studies have shown that upper cortical layer thinning occurs in progressive human multiple sclerosis (MS) and that cortical layer 2 and layer 3 (L2/3) excitatory neurons (L2/3ENs) that express CUT-like homeobox 2 (CUX2) are selectively vulnerable to degeneration<sup>2</sup>. The gene discussed is CUX2; the disease is multiple sclerosis.