John Fox, a 3-month-old Caucasian male infant, was brought to the emergency department of the hospital by his parents. Mrs. Fox tells Dr. Jones the attending physician, that John had vomited four times in the past 24 hours. He was becoming increasingly lethargic and having trouble breathing. Dr. Jones, the attending physician, notes that John had recently been admitted to the hospital with essentially the same symptoms. Dr. Jones orders blood and urine collections STAT. The bicarbonate and glucose levels were low. John was admitted to the ICU and received an immediate infusion of bicarbonate, dextrose and antibiotics. (Note that bicarbonate would be omitted in present therapy.)

John is the first-born child of Mr. & Mrs. Charles Fox. The pregnancy and delivery were normal. At birth John weighed 3.0 kg and was 50 cm in length (average). He has been breast fed since birth. Mrs. Fox indicates that she received good pre-natal care. She indicates that she does not smoke, drink alcohol, or take any medications. Mr. and Mrs. Fox have not suffered any serious health problems. Mrs. Fox is 23 years old and salesperson at a local drug store. Mr. Fox is 25 years old and is an auto mechanic.

Results from Physical Exam:

Results from Clinical Tests:

The ER physician felt that accidental poisoning was most consistent with these data, but did not rule out systemic infection, and /or a metabolic defect in the differential diagnosis. Which one of the metabolic defects below could you immediately rule out?

• A: Aminolevulinic acid (ALA) synthase-1 deficiency
• B: Homogentisate 1,2-dioxygenase deficiency
• C: Biotinidase deficiency
• D: Propionyl-CoA carboxylase deficiency
• E: Methyl-malonyl-CoA mutase deficiency

INSTRUCTIONS:

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3. Your team reporter should now enter your team's answer in Benware. The whole-class discussion of this application exercise will take place verbally as usual.