Metabolism USMLE Step 1 Practice Question
A 3 year old boy is brought in for developmental delay and involuntary writhing movements. He has a history of self mutilation with biting of his lips and fingers. Orange sand like crystals have been noted in his diaper. Which of the following enzyme deficiencies is the most likely cause?
Answer choices
- AXanthine oxidase
- BDihydroorotate dehydrogenase
- COrnithine transcarbamylase
- DHypoxanthine guanine phosphoribosyltransferaseCorrect answer
- EAdenosine deaminase
- FPhosphoribosyl pyrophosphate synthetase
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