Try it
Biochemistry · Glycogen storage diseases
Sample itemA child has severe fasting hypoglycaemia, hepatomegaly, lactic acidosis and hyperuricaemia. Which enzyme is deficient?
Original practice item, not a recalled exam question. Nothing here is recorded.
The answer and the reasoning
D. Glucose-6-phosphatase
Von Gierke disease (type I) is the failure of the final step of both glycogenolysis and gluconeogenesis, so the liver cannot release free glucose. Lactate and uric acid build up and the liver enlarges.
Option by option
A. Muscle glycogen phosphorylase
Muscle phosphorylase deficiency is McArdle disease, with exercise cramps.
B. Debranching enzyme
Debranching enzyme deficiency is Cori disease, milder, with normal lactate.
C. Acid maltase
Acid maltase deficiency is Pompe disease, with cardiomegaly and hypotonia.
D. Glucose-6-phosphatase (correct)
Correct. No free glucose can leave the liver.
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.
More Biochemistry questions
- Nucleotide metabolismA 4-year-old boy has intellectual disability, dystonia, self-mutilation and hyperuricaem…
- VitaminsA patient with megaloblastic anaemia and mild neurological signs has raised serum methyl…
- Amino acid metabolismA baby has a mousy odour, fair skin and developmental delay. Which enzyme is deficient?
- VitaminsWernicke encephalopathy results from deficiency of which vitamin?