FOXA2 and Hypoglycemia: In endoderm-specific FOXA2 knockout mice (FOXA2loxP/loxP; FOXA3Cre) (47), the initial steps of endocrine cell differentiation occurred normally, however, α cells did not complete terminal differentiation, as evidenced by a dramatic decrease in the number of mature α cells, leading to hypoglucagonemia and hypoglycemia as well as early mutant death.