Question

Glutamine is Increase in CSF, blood and urine, this is due to deficiency of

• A. CPS-I
• B. Arginase
• C. OTC
• D. Argininosuccinate synthetase

Answer 1

The Correct Option is A

In biochemistry, an increase in glutamine levels in the cerebrospinal fluid (CSF), blood, and urine can be attributed to a deficiency in an enzyme involved in the urea cycle. This condition is linked to the inability to process ammonia into urea, thereby causing the accumulation of ammonia and subsequently glutamine, which serves to detoxify ammonia by converting it to a less toxic form. 

The urea cycle involves several key enzymes, including Carbamoyl Phosphate Synthetase I (CPS-I), Ornithine Transcarbamylase (OTC), Argininosuccinate Synthetase, and Arginase. A deficiency in these enzymes disrupts the conversion of ammonia to urea, particularly affecting CPS-I, which is responsible for the initial step of the urea cycle that combines ammonia with bicarbonate to form carbamoyl phosphate. If CPS-I is deficient, ammonia accumulates, leading to elevated levels of glutamine in the fluids.

Figure 1 presents a simplified overview of the urea cycle and highlights the role of CPS-I:

Enzyme	Function
CPS-I	Combines ammonia with bicarbonate to form carbamoyl phosphate
OTC	Converts carbamoyl phosphate and ornithine to citrulline
Argininosuccinate Synthetase	Converts citrulline to argininosuccinate
Arginase	Releases urea and regenerates ornithine

In this question, the increased glutamine levels can be correctly attributed to a deficiency in CPS-I. This conclusion is drawn from the enzyme's pivotal role in the initial ammonia processing step, leading to its accumulation when the enzyme is deficient.