A 2-day-old female newborn presents with vomiting, tachypnea (RR 58/min), and progressive somnolence. Vital signs show HR 168/min, BP 65/40 mmHg, temperature 36.8°C, SpO2 98% on room air. Laboratory studies reveal plasma ammonia 480 μmol/L, blood urea nitrogen 8 mg/dL, and normal urinary orotic acid. Arterial blood gas demonstrates pH 7.48 with respiratory alkalosis. No hepatomegaly noted on examination. Which enzyme deficiency most likely explains these findings?
- A)Argininosuccinate synthetase
- B)Carbamoyl phosphate synthetase IGABARITO
- C)Ornithine transcarbamylase
- D)Pyruvate carboxylase
- E)Fructose 1 phosphate aldolase
Explicação
This infant has carbamoyl phosphate synthetase I deficiency. Failure of the first mitochondrial step of the urea cycle causes severe hyperammonemia with low BUN, but because carbamoyl phosphate is not being generated, there is no overflow into pyrimidine synth... Ver explicação completa e trilha adaptativa →