Metabolism USMLE Step 1 Practice Question
A 4-day-old female newborn presents with poor feeding, vomiting, hypotonia, and seizures. Vital signs reveal HR 155 bpm, RR 28/min, temp 37.2°C. Laboratory studies demonstrate high anion gap metabolic acidosis (pH 7.18), serum ammonia 185 μmol/L, elevated plasma propionyl-CoA derivatives, and positive urine ketones. Abdominal imaging shows no obstruction. She has not received antibiotics. Which of the following dietary substances should be most restricted in this patient?
Answer choices
- APhenylalanine and tyrosine
- BGalactose and lactose
- CLeucine, lysine, and tryptophan
- DFructose and sucrose
- EValine, odd chain fatty acids, methionine, isoleucine, and threonineCorrect answer
- FArginine and citrulline
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