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': 'Gyrate atrophy of retina is caused by accumulation of: \nSelect and explain. \nA. Ornithine, B. Arginine, C. Citrulline, D. none of the above', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Arginine is conveed to ornithine then to glutamate--semialdehyde. Subsequent catabolism to alpha-ketoglutarate occurs as described above for. Mutations in ornithine -aminotransferase elevate plasma and urinary ornithine and cause gyrate atrophy of the retina. Treatment involves restricting dietary arginine. Ref: Harper 28th edition, chapter 29.', 'role': 'assistant'}]