KROK 1 2013 – Question 160 · KROK (Medicine) · Biological Chemistry
Children with Lesch-Nyhan syndrome have a severe form of hyperuricemia accompanied by the formation of tophi, urate calculi in the urinary tracts, as well as serious neuro-psychiatric disorders. The cause of this disease is the reduced activity of the following enzyme:
- A. Karbamoyl phosphate synthetase
- B. Hypoxanthine-guanine phosphoribosyltransferase
- C. Xanthine oxidase
- D. Dihydrofolate reductase
- E. Thymidylate synthase
Hint
Think about the pathway that recycles free purine bases instead of degrading them to uric acid, and what builds up when that recycling fails.
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