Administration of exogenous glucagon induced a comparable rise in blood glucose in mutant and control mice, indicating that glucagon sensitivity was normal in Pdx-1-Creearly;VhlhLoxP/LoxP mice (Figure S3) and that hypoglycemia was not due to impaired liver response to glucagon, but most likely a result of deficient glucagon secretion. The gene discussed is PDX1; the disease is Hypoglycemia.