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Biochemistry 12

A 1-week-old boy is brought in by his mother to the emergency department for evaluation of a new onset seizure at home which occurred one hour ago. The mother states he has vomited several times today and has not been feeding well since yesterday. The infant was born healthy at term without complications. The mother had routine prenatal care throughout her pregnancy. On physical examination, the infant has a weak cry and appears to have low muscle tone. His diaper is notable for a sweet scent. Serum and urine amino acid tests are ordered which confirm the diagnosis.

Which of the following amino acids should not be given to this infant?

  • A) Arginine
  • B) Leucine
  • C) Phenylalanine
  • D) Tryptophan
  • E) Tyrosine


Karim Zaki


Dr. Ted O'Connell