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
HHH syndrome is due to deficiency of which enzyme? 
Select and explain. 
A. Arginase, B. Arginosuccinase, C. Ornithine transcarbomylase, D. None
C: Ornithine transcarbomylase
Answer: C: Ornithine transcarbomylase 
Explanation: Ans. is. c' i.e., Ornithine transcarbomylase Actually there is no molecular deficiency of any enzyme but functional deficiency.In HHH syndrome there is deficiency/defect in Ornithine transpoer across the mitochondrial membrane which causes functional deficiency of :?Ornithine transcarbomylaseOrnithine -8- aminotrans ferase (OAT)