The doctor examined a 4-month old infant brought to the emergency room after having a seizure. The infant also had a rash and odd odor. Further examination revealed an abnormally small head and fair skin. The doctor diagnosed the infant with phenylketonuria (PKU), a genetic disorder that prevents breaking down the amino acid phenylalanine, causing neurological problems if not treated through a specialized diet limiting high-protein foods. Testing confirmed high phenylalanine levels in the infant's blood and urine, supporting the PKU diagnosis.

1. CASE STUDY
BY: COURTNEY DUBBELS

2. SYMPTOMS OF INFANT X
• A four month old infant’s
parents have brought their
child to the emergency
room because the child
has had a seizure.
• The nurse also makes a
note of a rash and an odd,
musty odor that is coming
from the child.
•If you were the doctor
examining Infant X,
what would your first
diagnosis be for the
child?

3. FURTHER STUDY OF INFANT X
• As the doctor is
examining the child, he
notices that the child
seems to have an
abnormally small head,
fair skin, and blue eyes.
• Fair skin and blue eyes
are not uncommon, but
both parents have dark
•Knowing what you do
now, what would be
your diagnosis? Are you
going to stick with your
initial diagnosis or have
your changed your
mind?

4. DIAGNOSIS OF DISORDER
• The doctor determines that the child
most likely has phenylketonuria (PKU).
• This can affect a person’s metabolism
and cause permanent brain damage
leading to psychiatric disorders, mental
retardation, and behavioral, emotional
and social problems if not treated
• PKU is a genetic disorder caused when
the body is unable to breakdown the
amino acid, phenylalanine, and the
build up of it can cause neurological
problems.
• Phenylalanine is part of proteins and is
known to be in the composition breast
milk and many baby formulas and will
not show up until a baby is a few
months old.
• Both mother and father must pass on

5. TESTING FOR PKU
• Most baby have newborn screening done,
which will include testing for PKU.
• A PKU screening test is checking for
the enzyme, phenylalanine
hydroxylase, that breaks down
phenylalanine.
• To confirm if a child has PKU, follow-up
testing needs to be performed
• Follow-up testing will include testing
urine and blood for high amounts of
phenylalanine
• If a person is thinking about having a
child and knows that PKU runs in the
family, genetic tests can be performed to
know if future children are at risk for PKU

6. TREATMENT FOR PKU
• To prevent PKU from damaging the body further a special diet
that limits the amount of protein containing phenylalanine
needs to be implemented
• People with PKU will need to be tested regularly to check the levels of
phenylalanine in the blood.
• Milk, eggs, cheese, nuts, chicken, beef, pork, potatoes, and other foods
with high levels of proteins need to be limited
• The special diet needs to become a lifestyle
• Formulas have been created for people with PKU, so they can
get the required nutrients they need
• Sapropterin (Kuvan) is a drug that has been approved that will
help increase tolerance to phenylalanine

7. PKU IMPACT
• Most prevalent in people that are
Caucasian and Native American
• Costs around $10,000 per year to provide
the food and formula and around
$200,000 if they already have brain
damage.
• 38 states in the U.S. have mandates that
provide the food and formula, but many
are denied due to the requirements
• PKU does not mean death
• It becomes a lifestyle

8. MECHANISMS OF PKU
After consuming
phenylalanine…
• Some of it will be used to build
proteins, while the rest is broken
down in someone who is healthy
• The enzyme, phenylalanine
hydroxylase, that binds with
phenylalanine and breaks it down
into tyrosine.
• In someone who has PKU, there
is no enzyme to breakdown the
phenylalanine and it builds in
the body causing damage

9. PHENYLALANINE
• An essential amino acid in protein in foods
• The body cannot make it, so it has to be
consumed
• It’s converted into tyrosine that is needed for
creating L-dopa, epinephrine,
norepinephrine, and thyroid hormones
• It can be taken to treat chronic pain,
Parkinson disease, Vitiligo, depression, and
other diseases

10. FORMS OF PHENYLALANINE
•There are three forms
•D, L, and DL
• D is not found in nature and needs to be created
in a laboratory
• L is found in nature (proteins)
• DL is a combination of the two forms (racemic
mixture)
• D and L are mirror image of each other
(stereoisomer)

11. CLASSIFICATION OF PHENYLALANINE
• Classified as an essential amino acids that can’t be
found in the body along with leucine, isoleucine,
lysine, threonine, methionine, valine, and tryptophan
• All must be consumed
• It is an aromatic along with tryptophan and tyrosine.
• Includes an aromatic ring in its structure
• It is hydrophobic and nonpolar

12. REFERENCES
• http://www.newbornscreening.info/Parents/aminoaciddisorders/Images/Autosomal_R_I1.
gif
• http://www.mayoclinic.org/diseases-conditions/phenylketonuria/basics/risk-
factors/con-20026275
• http://www.webmd.com/children/tc/phenylketonuria-pku-topic-overview_#1
• http://www.mayoclinic.org/diseases-conditions/phenylketonuria/basics/tests-
diagnosis/con-20026275
• http://umm.edu/Health/Medical/AltMed/Supplement/Phenylalanine
• http://middletownhighschool.wikispaces.com/file/view/PKUpthwy.jpg/404165100/PKUpt
hwy.jpg
• http://www.biochemden.com/wp-content/uploads/2015/07/Phenylketonuria.png
• http://syversongen677s13.weebly.com/uploads/1/6/8/8/16888618/956107847.jpg
• https://s-media-cache-
ak0.pinimg.com/236x/aa/76/94/aa76941172318dc43f80d29903f1a976.jpg
• https://cbswdok2.files.wordpress.com/2016/05/3.jpg?w=532