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: Biochemistry
[{'content': 'Clinical manifestations of Lesch-Nyhan syndrome is due to the defective recycling of the following: \nSelect and explain. \nA. Purines, B. Methylcobalamin, C. Pyrimidines, D. Thiamine', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Lesch-Nyhan syndrome is a genetic disease, affecting almost solely males, of excessive synthesis of purines because of defective recycling and, therefore, uric acid production from their breakdown. Lesch-Nyhan syndrome is characterized by gouty ahritis but, in addition, affects the brain, resulting in mental retardation, loss of control of arm/leg/face movements, aggressive behavior, and self-mutilation by biting and scratching. Ref: Janson L.W., Tischler M.E. (2012). Chapter 4. Nucleosides, Nucleotides, DNA, and RNA. In L.W. Janson, M.E. Tischler (Eds), The Big Picture: Medical Biochemistry.', 'role': 'assistant'}]