This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Metabolism of carbohydrate, Subject name: Biochemistry
Von Gierke&;s occurs due to deficiency of 
Select and explain. 
A. Glucose-6-phosphatase, B. Liver Phosphorylase, C. Muscle phosphorylase, D. Debranching enzyme
A: Glucose-6-phosphatase
Answer: A: Glucose-6-phosphatase 
Explanation: Glycogen storage disease type I (GSD I) or von Gierke&;s disease, is the most common of the glycogen storage disease. This genetic disease results from deficiency of the enzyme glucose-6-phosphatase and has an incidence in the American population of approximately 1 in 100,000 bihs.Ref: DM Vasudevan, 7th edition, page no: 128