A child rapidly develops hypoglycemia after moderate activity. On physical examination, kidney and liver are found to be enlarged. Histopathology of liver shows deposits of glycogen in an excess amount. Blood examination reveals raised ketone bodies, lactic acid and triglycerides. Which enzyme is deficient in this patient?

Type Ia GSD-Von Gierke’s Disease: Most common Glycogen Storage Disorder (GSD) in childhood. Autosomal recessive. Glucose 6-phosphatase is deficient. The biochemical hallmarks are: Hypoglycemia Lactic acidosis Hyperlipidemia Hyperuricemia Clinical Presentation: Most commonly present at 3–4 months of age with: Doll like facies with fat cheeks Relatively thin extremities Short stature, protuberant abdomen Massive hepatomegaly Kidneys are also enlarged No splenomegaly Plasma may be milky due to associated hypertriglyceridemia. Key Concept:  Glucose 6-phosphatase is deficient in Von Gierke's disease. It is the most common glycogen storage disorder in childhood. Reference- Harper’s illustrated biochemistry. 30th edition page no: 179