This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: NEET 2019, Subject name: Biochemistry
Glutamine is increased in CSF, blood & urine in which defect: 
Select and explain. 
A. Arginosuccinate synthetase, B. OTC, C. CPS-I, D. Arginase
C: CPS-I
Answer: C: CPS-I 
Explanation: Defect in urea cycle Defect Enzyme involved Hyperammonemia type I Carbamoyl phosphate synthase I Hyperammonemia type II Ornithine transcarbamoylase Citrullinemia Arginosuccinate synthase Arginosuccinic aciduria Arginosuccinase Hyperarginemia Arginase In all enzyme deficiency ammonia will increase but cps 1 is rate limiting enzyme so it will increase ammonia most & and increase in ammonia lead to increase in glutamine. NOTE: The only urea cycle disorder that is inheritedX-linked recessively ishyperammonemia type II.