phenylketonuria (PKU)

Question 1

deficient phenylalanine hydroxylase (phenylalanine → tyrosine) or co-factor for phenylalanine hydroxylase: tetrahydrobiopterin (BH4)
↓ tyrosine (now essential aa)
↑ phenylalanine (neurotoxic)→ ↑ phenylketones (not neurotoxic)
tx: tyrosine, avoid phenylalanine foods

Answer 1

phenylketonuria (PKU)

Question 2

types of phenylketones

Answer 2

phenylacetate
phenyllactate
phenylpyruvate

Question 3

neurotoxicity of excess phenylalanine from PKU

Answer 3

growth retardation
mental retardation
seizures
fair skin
eczema
musty body odor

Question 4

musty body odor

Answer 4

PKU: phenylketonuria

Question 5

screening for PKU

Answer 5

2-3 day old infant
must wait for phenylketones to build up to a measureable level in urine
maternal source of tyrosine in utero
breastmilk contains phenylalanine →↑ phenylketones in urine

Question 6

treatment of PKU

Answer 6

must treat within few weeks of life: otherwise effects
avoid phenylalanine: aspartame, dairy products, meat, fish, chicken, eggs, beans, nuts
add tyrosine into diet
+/- add BH4

Question 7

complications of pregnant mom with untreated PKU

Answer 7

maternal phenylalanine/phenylketones are toxic to fetus: 
microcephaly
ID
growth retardation
congenital heart defects