A 2-week-old boy presents with poor feeding and lethargy. Vital signs show HR 145 bpm, RR 32/min, BP 68/42 mmHg, temperature 37.2°C. Laboratory studies reveal high anion gap metabolic acidosis (pH 7.21, HCO3 12 mEq/L), ketonemia, hyperammonemia (156 μmol/L), and elevated methylmalonic acid. Serum glucose is normal. He denies vomiting. Which of the following deficiencies best explains these findings?
- A)Dihydrofolate reductase deficiency
- B)Ornithine transcarbamylase deficiency
- C)Biotin deficiency only
- D)Vitamin B12 deficiency or methylmalonyl CoA mutase deficiencyGABARITO
- E)Thiamine deficiency
Explicação
This infant has methylmalonic acidemia, which results either from methylmalonyl CoA mutase deficiency or from vitamin B12 deficiency because B12 is the required cofactor. Accumulation of methylmalonic acid produces metabolic acidosis and can inhibit the urea c... Ver explicação completa e trilha adaptativa →