Sox9 is expressed by BECs at baseline in adult mice and in reactive BECs during liver injury, but there is ectopic expression of Sox9 in hepatocytes during forms of cholestatic liver injury such as biliary atresia [26] and ornithine transcarbamylase deficiency [27] in humans and DDC diet [28, 29] and rarely after choline-deficient and ethionine-supplemented diet [30] in rodents. Here, SOX9 is linked to hyperinsulinemic hypoglycemia, familial, 4.