Glycogen storage disease: von Gierke: practice question

A Biochemistry question in the style of the NEET PG paper. Answer it first, then read why the right option is right and why each of the others is wrong.

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Biochemistry · Glycogen storage disease: von Gierke

Sample item

An infant has severe fasting hypoglycemia, hepatomegaly, lactic acidosis, hyperuricemia, and hypertriglyceridemia. Which enzyme deficiency is most likely?

Original practice item, not a recalled exam question. Nothing here is recorded.

The answer and the reasoning

B. Glucose-6-phosphatase deficiency

Von Gierke disease is glucose-6-phosphatase deficiency, preventing release of free glucose from liver and kidney. Accumulated glucose-6-phosphate is diverted to lactate, lipid, and purine pathways.

Option by option

  • A. Muscle glycogen phosphorylase deficiency

    Muscle phosphorylase deficiency causes exercise intolerance rather than severe fasting hypoglycemia.

  • B. Glucose-6-phosphatase deficiency (correct)

    Correct. This enzyme defect causes the classic severe fasting-metabolic phenotype.

  • C. Debranching enzyme deficiency

    Debranching-enzyme deficiency causes limit-dextrin accumulation and milder hypoglycemia.

  • D. Lysosomal acid alpha-glucosidase deficiency

    Acid alpha-glucosidase deficiency causes Pompe disease with cardiomyopathy and hypotonia.

Source note: Original NextPrep sample item — pending expert review. This item is original practice material awaiting independent expert review, so confirm important facts in a standard textbook.

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Questions about this Biochemistry question

What is the answer to this Biochemistry question?

The best answer is B, Glucose-6-phosphatase deficiency. Von Gierke disease is glucose-6-phosphatase deficiency, preventing release of free glucose from liver and kidney.

Why is "Muscle glycogen phosphorylase deficiency" not the answer?

Muscle phosphorylase deficiency causes exercise intolerance rather than severe fasting hypoglycemia.

Why is "Debranching enzyme deficiency" not the answer?

Debranching-enzyme deficiency causes limit-dextrin accumulation and milder hypoglycemia.

Why is "Lysosomal acid alpha-glucosidase deficiency" not the answer?

Acid alpha-glucosidase deficiency causes Pompe disease with cardiomyopathy and hypotonia.

What concept does this question test?

It tests Glycogen storage disease: von Gierke in Biochemistry. Accumulated glucose-6-phosphate is diverted to lactate, lipid, and purine pathways.

How hard is this question?

We tag it as an application question: it asks you to use a fact on a patient or a finding. The tag is our own editorial judgement, not an official difficulty rating, so read the reason for every option, not only the answer.

How should I study Glycogen storage disease: von Gierke?

Build one table of enzyme deficiency, disease, inheritance and key finding, then revise it by spaced recall. Then use the flashcards and the other Biochemistry questions on this site to test what stuck.

Is this a real NEET PG question?

No. It is an original practice item (editorial status: sample, version 1). NextPrep does not publish recalled or leaked questions, and independent faculty review of this item has not been completed yet, so confirm important facts in a standard textbook.