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Flashcards in PKU Deck (15)
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1
Q

Children w/ untreated PKU rarely reach IQ over __

A

50

2
Q

Urine in people w/ PKU

A

. Metabolites make urine musty

. Phenylpyruvate found in urine

3
Q

Neonatal screening of PKU

A

. Neonates initially have no signs or symptoms
. Screening mandatory in every state
. Done at 49 hours of age because parent clears excess Phe in utero
. Guthrie screening test identifies PKU in babies

4
Q

Prenatal diagnosis of PKU

A

. Gene for PAH located on chromosome 13
. Contains 13 Exons separated by introns
. DNA analysis can be done to identify markers
. Restriction fragment length polymorphism (RFLP) used to carry out prenatal diagnosis

5
Q

PKU treatment

A

. Must start in first 7-10 days to prevent intellectual disability
. Lifelong restriction of dietary Phe
. Synthetic amino acid preparations used
. Can supplement w/ some natural foods (fruits, veggies, some cereals)
. Tyr can’t be synthesized from Phe and must be supplied in diet

6
Q

Function of dihydropteridine reductase

A

Converts BH2 to BH4
. Enzyme can be mutated causing PKU
. BH4 also needed for Tyr hydroxylase that catalyze rxns for serotonin and catecholamine synthesis that is affected again

7
Q

High Phe effects on transport in brain

A

. High concentrations of Phe inhibit transport of Tyr and Trp into brain and inc. Phe to brain
. Inc. possibility of neurotransmitter dysfunction
. Abnormal brain myelination and deficiency of brain large neutral AA can play role in impaired cognition

8
Q

Skeletal changes seen in PKU

A

. Small head
. Short stature
. Flat feet

9
Q

Movement symptoms in PKU

A

. Eczema
. Tremors
. Jerking of arms or legs
. Unusual hand posturing

10
Q

Current method for PKU screening

A

. Mass spec
. Allows analysis for multiple diseases
. Positive tests followed up w/ specific tests

11
Q

Normal limits of Phe in people w/ PKU

A

2 and 6 mg/dl

12
Q

Challenges of dietary control

A

. Bland die
. Social implications: can’t eat most foods that peers consume
. Economic and health care systems barriers: cost of low Phe can be high expiate it being considered a medical food

13
Q

Synthetic BH4

A

. Causes residual PAH enzyme activity to inc. to reduce blood Phe levels
. Effective in dec. blood Phe in some people w/ PKU
. Only effective in people that have some normal PAH activity

14
Q

Phe uptake blockers

A

. Large neutral amino acids (LNAA’s) block Phe uptake through digestive tract

15
Q

Maternal PKU

A

. Mom’s have PKU
. High level Phe cause microcephaly, intellectual disability, and heart abnormalities in fetus
. Can cause miscarriage, growth retardation, craniofacial dysmorphic features
. Take effect in 1st trimester
. Need strict control over diet before conception and continued throughout pregnancy

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