This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Metabolism of carbohydrate, Subject name: Biochemistry
Essential pentosuria is due to defect in 
Select and explain. 
A. HMP pathway, B. Glycolysis, C. Gluconeogenesis, D. Uronic acid pathway
D: Uronic acid pathway
Answer: D: Uronic acid pathway 
Explanation: It is an inborn error of metabolism.In the pathway, L-xylulose is conveed to D-xylulose by two enzymes, xylitol dehydrogenase, and xylulose reductase.Absence of any of these enzymes leads to pentosuria.Ref: DM Vasudevan, 7th edition, page no: 135