A toddler presents with failure to thrive and progressive hepatosplenomegaly. Liver biopsy shows glycogen with very few branch points, resembling amylopectin. The child develops portal hypertension and cirrhosis, and dies of hepatic failure in early childhood. Blood glucose and lipid profile are near normal. Which enzyme is deficient?
- A Liver glycogen phosphorylase
- B Glycogen debranching enzyme (alpha-1,4-glucanotransferase)
- C Glycogen branching enzyme (amylo-(1,4 to 1,6)-transglucosidase) ✓
- D Acid alpha-glucosidase
Correct answer: C. Glycogen branching enzyme (amylo-(1,4 to 1,6)-transglucosidase)
Explanation
Andersen disease (GSD type IV) results from branching enzyme deficiency. Glycogen is synthesized with long outer chains and few alpha-1,6 branch points (polyglucosan), which is poorly soluble and triggers foreign-body-type fibrosis, causing progressive cirrhosis and hepatic failure. Debranching enzyme deficiency is type III, which spares the liver from cirrhosis and shows short, highly branched limit dextrin instead.
Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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