Since these FP progenitors expressed EN1, WNT5A, RAX, and CHL1, and some of the FOXA2+ cells also double-positive for NKX2.1 (Figures 2B and 2F), we therefore hypothesize that these FP progenitors derived under AD conditions bear a diencephalic or a midbrain regional identity. The gene discussed is RAX; the disease is Alzheimer disease.