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
Pentosuria is due to defect in which pathway? 
Select and explain. 
A. Glycolysis, B. Polyol pathway, C. Uronic acid pathway, D. Kreb's cycel
C: Uronic acid pathway
Answer: C: Uronic acid pathway 
Explanation: Essential Pentosuria i. It is one of the members of the Garrod&;s tetrad. The incidence is 1 in 2,500 bihs. ii.It is an inborn error of metabolism, due to defect in glucuronic acid pathway of glucose. In the pathway, L-xylulose is conveed to D-xylulose by two enzymes, xylitol dehydrogenase and xylulose reductase absence of any of this enzyme lead to pentosuria.Ref: DM Vasudevan, 7th edition, page no: 134