PKU Clinical Correlation Flashcards
If a child is untreated for PKU, when do symptoms of the disease start becoming apparent?
6 months you can see developmental and growth delay in the children
What are some cutaneous symptoms of PKU?
Pigment Dilution, lighter skin and eyes
What is the mode of inheritance for PKU?
Autosomal Recessive
What does phenylalanine get converted to to as it begins building up in PKU (2 things)?
- Hydroxyphenylacetic Acid
- Phenylacetic Acid
**Collectively these are called phenylketones
What is significant about phenylalanine being an essential amino acid?
You can cut back on it and the body won’t be able to make more
What enzyme is deficient in PKU?
Phenylalanine Hydroxylase
When do you start to see elevated levels of phenylketones in newborns with PKU?
1 month
What is the site of dysfunction in PKU?
- Site of damage?
- Liver = major enzyme dysfunction
- CNS = major site of damage
If a baby has PKU should you limit all of the phenylalanine in their diet?
NO - its essential to have all amino acids so small amounts should be given
What is the maximum amount of time a newborn can go without being screened in a hospital?
48 hours, for normal kids its 24 hours
What would you expect to see on the mass spectrum of an individual affected by PKU, that was untreated?
- HIGH - Phe
- LOW - Tyr
T or F: females with PKU don’t have to worry about their disease affecting their children
False, All females have a maternal effect where their elevated levels of PKU will have a negative affect on the child, also the disease is autosomal recessive so it could be passed on
What two requisites classify an individual as having classical PKU?
- > 20 mg% Phe
- Tyr normal to low
- Phenylketones present
What does the following individual have:
4-10 mg% phe
Tyr normal, Phenylketones negative
untreated with no cognitive impairment
Non-PKU Hyperphenylalaninemia (HPA)
What does the following individual have?
10-20mg% phe
Tyr normal, Phenylketones variable
Variant PKU
Which individuals are most likely to respond to BH4 treatment?
Those with the milder forms like HPA and Variant PKU
T or F: all PKU is a phe Hydroxylase defect
False
What are some other causes of PKU? (name 5)
- Hypertyrosinemia
- Immature Liver
- Total Parenteral Nutrition (TPN) - excess amounts of Phe in IV
- Increased Conc. of Blood on the Spot
- Cofactor abnormalities
What percentage of PKU cases result from common mutations?
- Private Mutations?
- Common Mutations - 30-50% cases
- Private Mutations - 50-70% cases
If people are BH4 responsive what modifications can you make to their diet?
- You don’t have to be so harsh
LOOK AT THESE SLIDES AGAIN BEFORE EXAM
_________
T or F: the mother’s circulating metabolites can hurt the fetus if she has PKU
True
