THEME AND FOCUS: UREA CYCLE Case Study: A patient presented to casualty with nausea, vomiting. Intravenous glucose was given and the patient recovered. After few months, patient presented with same complaints. Blood glutamine was found to be increased. Also uracil levels were raised. Lead Question: What is the diagnosis?
Glutamine increase or Hyperammonemia is a common feature of all the urea cycle enzyme but in this case uric acid levels are also increased so it is more specifically indicating ornithine Trans Carbamoylase deficiency (See fig and treasure) and not other enzymes. Hence the diagnosis is OTC deficiency. NOTE:- CPS-II (Carbamoyl Phosphate Synthetase-II) is enzyme involved in pyrimidine synthesis, not in urea cycle.
CPS-I deficiency
Arginino succinate synthetase deficiency
CPS-II deficiency
Ornithine trans carbamoylase deficiency
Urea cycle