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': 'Which is not pyridoxine dependenta) Homocystinuria b) Maple syrup urine diseasec) Oxaluriad) Xanthinuria \nSelect and explain. \nA. c, B. bd, C. ab, D. ac', 'role': 'user'}, {'content': "Answer: B \nExplanation: Pyridoxal phosphate-dependent conditions are homocystinuria, cystathioninuria, oxaluria and xanthurenic aciduria.\nDon't get confused option d (xanthinuria) with xanthurenic aciduria. Both are different conditions\n\n\nIn xanthurenic aciduria, there is excretion of xanthurenic acid (xanturenate), an alternative metabolite of tryptophan metabolism. This is pyridoxine-dependent.\nIn xanthinuria, there is excessive excretion of xanthine in the urine. This is due to deficiency of enzyme xanthine oxidase and it is not pyridoxine responsive.\n\nAbout option b\n\nMaple syrup urine disease is due to defective branched chain u-ketoacid dehydrogenase enzyme, and it may be associated with thiamine (vitamin B1) deficiency.", 'role': 'assistant'}]