FBP1 and pyruvate carboxylase deficiency disease: Although FBP1 deficiency is usually included in the differential diagnosis of ketotic hypoglycemia with other disorders (e.g., beta-ketothiolase deficiency, pyruvate carboxylase deficiency, respiratory chain defects, and hereditary fructose intolerance), the lack of ketosis may lead to an initial misdiagnosis with non-ketotic hypoglycemic conditions, such as fatty acid oxidation defects and glycogen storage disease type 1 [3, 18].