A 6-day-old male newborn presents with poor feeding, vomiting, and alternating hypotonia and hypertonia with intermittent opisthotonos. Vital signs reveal HR 148/min, RR 32/min, and temperature 37.2°C. His urine has a characteristic sweet odor. Laboratory studies demonstrate elevated plasma branched-chain amino acids (leucine 850 μmol/L; normal <200), elevated urine branched-chain α-ketoacids, and normal glucose. He denies seizure activity. Which enzyme deficiency is most likely responsible?
- A)Ornithine transcarbamylase
- B)Phenylalanine hydroxylase
- C)Tyrosinase
- D)Homogentisate oxidase
- E)Branched chain alpha ketoacid dehydrogenaseGABARITO
Explicação
This newborn has maple syrup urine disease due to deficiency of branched chain alpha ketoacid dehydrogenase. Accumulation of leucine, isoleucine, and valine and their ketoacids causes neonatal encephalopathy and the characteristic sweet smelling urine. Early r... Ver explicação completa e trilha adaptativa →