In mice, conditional deletion of FoxO1, FoxO3, and FoxO4 was found to affect formation of hematopoietic stem cells and neural stem/progenitor cells [20,21], and compromised pancreatic β cell function, leading to maturity-onset diabetes of the young (MODY)-like diabetes [22]. The gene discussed is FOXO4; the disease is type 2 diabetes mellitus.