Mod 6-6 PKU Flashcards
What does PKU stand for?
Phenylketonuria
PKU is the most common what?
Hereditary abnormality that is an enzyme deficiency.
What is the definition of PKU?
A congenital disorder in which the enzyme that metabolizes the protein phenylalanine is deficient and toxic amounts of the protein are allowed to build up in the blood stream.
What can happen if the deficiency that causes PKU is not treated early?
Brain atrophy (loss of neurons and connections) will occur that can lead to a variety of dire consequences for the child.
What is the etiology of PKU?
The disease is passed through both parents who appear healthy but both show signs of the disease. It is transmitted recessively.
For parents that appear healthy but are both positive for PKU have a one in ____ chance of having a child with PKU and those children have a one in ___ chance of being a carrier like their parents.
4; 2
What is required at birth in reference to PKU?
being tested is required in the U.S.
How does PKU affect the skin?
- Lacks normal pigmentation (melanin)
- Excessively sensitive to light
- Eczema.
What do people with PKU usually have for hair and eye color?
Blond hair and blue eyes, but not always.
Excess PHE can also prevent normal _____ development.
brain
___% of PKU cases are in the classic form.
90%
When do the levels of phenylalanine begin to rise because the enzyme taht is needed to convert it ot another product is missing in a child born with PKU?
At about 3 or 4 days old
What happens if PKU is left untreated after birth?
Seizures begin, abnormal behavior becomes apparent including hyperactivity and extreme irritability, severe vomiting and abnormal EEG’s will be recorded. All of these will begin at about 4 months of age. Motor skills are also delayed (sitting, walking)
What happens with an untreated PKU patient at age 2-3 years old?
- Cerebral damage is severe with IQ averaging about 20.
- Children will also have unusual mousy odor
Can patients with PKU prevent mental retardation?
Yes with a phenylalanine-free diet
What are the clinical manifestations of PKU?
- Retardation
- Melanin deficiency
- Slow motor skills development
- Abnormal behavior
- Unusual body odor
What is seen radiographically with PKU patients?
Not much to see except dilated ventricles of the brain and as the disease progresses the brain is compressed and atrophied (thus causing low IQ in untreated children)
What is the radiographic effect of PKU?
None
What is phenylaline converted to in someone who does not have PKU?
tyrosine
Another term for profound retardation that PKU can lead to…
microcephaly - an abnormal smallness of the head
