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Old 07-24-2012
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Urine Sample Mousy Odor Urine!

A 4-month-old infant girl is brought to the pediatrician for evaluation of decreased attention to her surroundings and a noticeable twitch. Her urine has a mousy odor, and laboratory studies show a positive Guthrie test. Which metabolic intermediate is most likely to be produced in lower amounts in this patient?

a) Dihydroxyphenylalanine
b) Phenylalanine
c) Phenyllactic acid
d) Phenylpyruvate
e) Tyrosine


btw. it's a bit funny for me to read that a 4-month-old infant has a decreased attention to her surrounding
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Old 07-24-2012
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Answer is E
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Old 07-25-2012
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Phenylketonuria - AR disease - characterised by def. of the enzyme
phenylalanine hydroxylase involved in hydroxylation of PA to tyrosine.

Phenylalanine -----///-------- tyrosine.

E - tyrosine levels are reduced.

phenylalanine levels increased and the other pathways of decarboxylation and transamination lead to increase levels of phenylacetate,
phenylpyruvate and phenyllactate.
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  #4  
Old 07-28-2012
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Correct Answer correct answer :)

The answer is E) Tyrosine

The results of the Guthrie test, which measures blood phenylalanine, shows that this patient has phenylketonuria (PKU). In PKU, a deficiency of phenylalanine hydroxylase prevents synthesis of tyrosine.
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