A previously healthy 7-month-old develops vomiting, sweating, and hypoglycemia 30 minutes after being introduced to fruit juice and mashed banana. Liver biopsy after an episode shows accumulation of fructose-1-phosphate. Which enzyme is deficient?
- A Aldolase B ✓
- B Fructokinase
- C Fructose-1,6-bisphosphatase
- D Triose kinase
Correct answer: A. Aldolase B
Explanation
Hereditary fructose intolerance results from aldolase A deficiency. Fructokinase converts fructose to fructose-1-phosphate normally, but it cannot be cleaved, so it accumulates and traps phosphate, inhibiting glycogenolysis and gluconeogenesis to cause hypoglycemia. Fructokinase deficiency causes benign essential fructosuria with no symptoms. Fructose-1,6-bisphosphatase deficiency causes fasting, not dietary fructose, provoked hypoglycemia.
Reference: Harper's Illustrated Biochemistry, 32nd ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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