CASE STUDYBY: COURTNEY DUBBELS

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?

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 brown eyes and are of Native American descent.

•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?

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 the

gene for the child to have PKU because of the recessive nature of the disorder

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

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

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

MECHANISMS OF PKUAfter 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

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

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)

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

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/PKUpthwy.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• http://npkua.org/portals/0/pdfs/talking_points.pdf• https://www.researchgate.net/figure/276147597_fig1_Figure-1-Conceptual-model-of-the-impact-

of-phenylketonuria-PKU-and-its-treatment-on