This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Pathology
[{'content': 'A 4-year-old male with mental retardation, self-mutilation, and hyperuricemia is likely to have a deficiency of an enzyme involved in the: \nSelect and explain. \nA. Conversion of homogentisic acid to methylacetoacetate, B. Degradation of galactocerebroside, C. Breakdown of branched-chain amino acids, D. Recycling of guanine and hypoxanthine', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Adenosine deaminase is an enzyme that is deficient in individuals with the autosomal recessive form of SCID, and hypoxanthine-guanine phosphoribosyl transferase (HGPRT), an enzyme of the purine salvage pathway for recycling guanine and hypoxanthine that is deficient in individuals with the X-linked recessive disorder Lesch-Nyhan syndrome.', 'role': 'assistant'}]