A 6-month-old infant presents with hypoglycemia, hepatomegaly, and lactic acidosis after fasting. Liver biopsy shows marked glycogen accumulation. Enzyme assay reveals deficiency of glucose-6-phosphatase. Which metabolic process is PRIMARILY impaired in this child?

• A Glycogen synthesis
• B Uptake of glucose by peripheral tissues
• C Beta-oxidation of fatty acids
• D Release of free glucose from the liver into circulation ✓

Explanation

Glucose-6-phosphatase is the key enzyme in both glycogenolysis and gluconeogenesis that hydrolyzes glucose-6-phosphate to free glucose in the liver. Its deficiency (von Gierke disease, GSD type Ia) prevents hepatic glucose output, causing fasting hypoglycemia and compensatory glycogen accumulation. Lactic acidosis results from substrate diversion into anaerobic glycolysis and lactate production.

Reference: Harper's Illustrated Biochemistry, 32nd ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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