FOXA1 and Hyperglycemia: In conclusion, although FOXA1 is not required for the initial specification of pancreatic Β cell, the terminal differentiation to fully mature Β cell is dependent on FOXA1 expression (37).In addition, lack of Groucho-related gene3/4-mediated repression leads to ectopic expression of FOXA1, which represses the expression of the Β cell transcription factor gene Neurod1, leading to loss of Β cell proliferation, early lethality, and hyperglycemia (38).