FBP1 and Glycogen storage disease due to glycogenin deficiency: Due to the disease's nonspecific clinical features, differential diagnoses such as glycogen storage diseases (GSDs) and mitochondrial diseases (MDs) should be considered at first and ruled out before confirming enzymatic defects such as FBP1 deficiency, as these conditions also present with similar symptoms of hypoglycemia and hyperlactatemia [11].