PDX1+NKX6.1+/high pancreatic endoderm cells derived from human PSCs mature into functional β cells and improve hyperglycemia when transplanted into immunodeficient diabetes model mice, whereas human PSC-derived PDX1+NKX6.1+/low cells differentiate into polyhormonal cells and do not functionally mature13. The gene discussed is PDX1; the disease is diabetes mellitus.