A 7-month-old infant presents with history of vomiting & failure to thrive. Patient improved with IV glucose. After one month, returns with same complaints. On evaluation, found to have high glutamine and uracil. Which is the likely enzyme defect?
b. Ornithine transcarbamylase(Ref: Nelson Textbook of Pediatrics, 19/e p447-450; Nelson's 20/e p 669-674)Discussing about the findings of each of the above enzyme deficiencies, one by one.a. CPS1* Hyperammonemia with markedly increased glutamine and alanine* Urinary orotic acid is usually low or may be absentb. Ornithine transcar-bamylase* Hyperammonemia with elevated plasma glutamine and alanine* Hyperammonemia with elevated plasma glutamine and alanine)c. Arginase* Marked elevations of arginine in plasma and CSF* Urinary excretion of orotic acid, arginine, lysine, cystine, & ornithine are increasedd. Arginosuccinase lyase* Increase in plasma argininosuccinic acid, citrulline glutamine and alanine* Argininosuccinic acid is found in large amounts in urine and spinal fluid* Note: Orotic acid, (elevated in OTC deficiency) converts to Uracil via Pyrimidine pathway.
CPS1
Ornithine transcarbamylase
Arginase
Arginosuccinase lyase
Inborn Errors of Metabolism