PHENYLKETONURIA Flashcards
Phenylketonuria is a disease of
metabolism
PKU in an inherited
autosomal recessive trait
In PKU, the infant lacks what liver enzyme
Phenylalanine hydroxylase
is necessary to convert phenylalanine into tyrosine
Phenylalanine hydroxylase
a precursor of epinephrine, T4, and melanin
Tyrosine
a breakdown product of phenylalanine
The metabolite phenylpyruvic acid
The metabolite phenylpyruvic acid causes the urine to have a
typical musty or “mousy” odor
without adequate ____, the child fails to meet average growth standards.`
T4
atopic dermatitis
Eczema
Tyrosine is necessary for building
*body pigment
*and T4
without Tyrosine, the child is
blue-eyed with very fair skin and light blonde hair
Infant with ________ needs to be rescreened for PKU at a well-child visit.
Atopic Dermatitis
PKU is found in one of every _______ births in the US
10,000 births
PKU rarely occurs in people of
Africa or Jewish ancestry
If PKU remains untreated, the child will be left with
*an IQ below 20
*muscular hypertonicity
*spasticity
*possible recurrent seizures
PKU cannot be detected by amniocentesis because
Phenylalanine levels does not rise in utero
can be used for carrier detection and prenatal diagnosis from maternal serium
Recombinant DNA techniques
All infants in the United States are screened at birth by
Blood Spot Analysis
When are infants screened at birth by Blood Spot Analysis
after receiving 2 full days or breast or formula feedings.
Blood Spot Analysis test of infants are repeated at what week
at the second week of life during healthcare visit.
has been the main treatment of PKU for over 50 years and remains the main therapy.
Dietary Restriction
works by increasing tolerance to phenylalanine
The drug Sapropterin
Infants in whom PKU is detected during the first days of life are placed on what formula
Lofenalac
formula that is extremely low in phenylalanine
Lofenalac
a low amino acid formula can cause stools to be
loose
Foods highest in phenylalanine are those that are rich in
protein
Foods highest in phenylalanine are those that are rich in protein, such as
*meats
*eggs
*milk
Foods low in phenylalanine include
*orange juice
*bananas
*potatoes
*lettuce
*spinach
*peas
A formula such as Lofenalac can be used to prepare some foods, such as
*ice cream
*milk shakes
*birthday cakes
*puddings
Children need their blood and urine monitored frequently for phenylalanine levels which should be below
below 8 mg per dL
Because the diet tends to be high in carbohydrates to replace protein, children need to be screened for
Obesity
Prior to pregnancy, it is important to follow what type of diet
strict low-phenylalanine diet for about 3 months before conception and remain on the diet for the duration of pregnancy.
Phenylketonuria (PKU), a rare metabolic disorder characterized by
an inability to metabolize the amino acid phenylalanine
Plays a critical role in the synthesis of thyroid hormones
Tyrosine
Tyrosine synthesize thyroid hormones such as
*triiodothyronine (T3)
*Thyroxine (T4)
