A 3 day old male newborn develops progressive lethargy, poor feeding, and tachypnea. He becomes difficult to arouse but has no hepatomegaly. Laboratory studies show markedly elevated ammonia, low blood urea nitrogen, respiratory alkalosis, and increased urinary orotic acid. Which of the following enzyme deficiencies is the most likely cause?
- A)Carbamoyl phosphate synthetase I
- B)Methylmalonyl CoA mutase
- C)Ornithine transcarbamylaseGABARITO
- D)Arginase
- E)Argininosuccinate lyase
Explicação
This newborn has ornithine transcarbamylase deficiency, the most common urea cycle disorder. Excess mitochondrial carbamoyl phosphate is shunted into pyrimidine synthesis, causing elevated orotic acid, while failure to detoxify ammonia causes hyperammonemia an... Ver explicação completa e trilha adaptativa →