BIOCHEMISTRY 3 - Phenylketonuria (PKU) Report: Detailed Analysis

This report provides a detailed overview of Phenylketonuria (PKU), a rare genetic disorder characterized by the body's inability to break down phenylalanine, an amino acid. The report explores the symptoms of PKU, which can range from mild to severe, including seizures, stunted growth, and intellectual disabilities if left untreated. It explains the genetic causes, focusing on defects in the PAH gene. The report also covers diagnostic methods, such as newborn screening and blood tests, and treatment options including special diets restricting phenylalanine intake, and medication like sapropterin. Furthermore, it discusses the implications of PKU during pregnancy and preventive measures. The report concludes with a list of references.

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Table of Contents
Phenylketonuria..........................................................................................................................2
Symptoms...................................................................................................................................2
Causes........................................................................................................................................3
Ways of Diagnosis.....................................................................................................................4
Options of Treatment.................................................................................................................4
Diet.........................................................................................................................................4
Medication..............................................................................................................................5
Pregnancy and PKU...................................................................................................................5
Prevention of PKU.....................................................................................................................6
References..................................................................................................................................7

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Phenylketonuria
Phenylketonuria is a rare condition of genes and the reason is an amino acid known as
phenylalanine to construct inside the human body. The amino acids are most important parts
of proteins. Phenylalanine is found in every protein and some sweeteners those are artificial
(1).
The phenylalanine hydroxylase is a kind of enzyme that the body utilizes to convert
the phenylalanine into tyrosine that the human body needs in order to develop
neurotransmitters known as dopamine and epinephrine. The PKU is a genetic defect that
assists to develop phenylalanine hydroxylase. When this type of enzyme is not present, the
human body cannot break down the phenylalanine. This cause phenylalanine to construct up
in the body.
Babies those are born in United States are treated for PKU after birth. The symbols
and indications of PKU are very rare in United States and they are screened as early showing
permits healing to start after birth. Early analysis and action can assist to relieve the
indications of PKU and then stop the harm on brains

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(Figure 1: PhenylKetonuria)
Symptoms
The symptoms of PKU can start from gentle to severe. The harsh form of PKU is called
classic PKU. An baby that is born with classic PKU will not have anything for the first few
months (2). If the baby is not taken care of for PKU throughout this time of the birth, they
will have the following indications:
 Seizures
 Shaking, trembling or tremors
 Stunted growth
 Conditions of skin called eczema
 Hyperactivity
 A bad odour of their skin, breath and urine
If PKU is not evaluated at birth and the treatment of the disease is not started quickly, the
disease can cause

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 Problems of behaviours and seizures in adults
 Brain damage those are irreversible and intellectual disabilities with the few months of
the new born infants
A less harsh kind of PKU is alternative PKU. This takes place when the newborn infant
has too much phenylalanine in the body. The newborn baby with this kind of the disease can
have symptoms those are not severe. The infant need special diet in order to the disabilities
those are intellectual. Once the particular diet and other required treatment are started, the
indications begin to vanish. Persons who are diagnosed with PKU should direct the diet so
that the symptoms start diminishing
(Figure 2: Formation of the Phenylketonuria)
Causes
PKU is a state that is present at birth and it is caused due to fault in the PAH gene.
The gene of PAH assists in order to develop phenylalanine hydroxylase, the enzyme that is
responsible in order to break down the Phenylalanine. A hazardous construct of the

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phenylalanine can take place when someone eats foods that contain high proteins such as
meats and eggs (3). Both the parents of the child have to pass on a vision that is faulty of the
PAH gene for their child in order to succeed to the disease. If one the parents bypass a
modified gene then child will not have indications, but the child will be a transporter of the
gene.
Ways of Diagnosis
The united States have screened the newborn infants routinely for PKU by taking a
sample of blood. A doctor utilises a needle in order to take few drops of blood from the heel
of the baby in order to test for PKU and other disorders related to genes. The screening test is
conducted when the newborn baby is two to three months old and they are still in the hospital
(4). Extra tests can be conducted in order to confirm the results those are initial. These tests
search for the Mutation of PAH gene that causes the disease. These tests are conducted within
six weeks after they are born. If an adult or child shows PKU symptoms, such as delays in
developments, the doctor will give an order to the adult to conduct a blood test in order to
verify the diagnosis. This test includes taking a blood sample and then evaluating it for
existence of enzymes required in order to break down the phenylalanine.
Options of Treatment
People diagnosed with PKU relieve the symptoms and prevent the complications by
following an appropriate diet and then taking medications.
Diet
The major way in order to perform the treatment of PKU is to have a special diet that
restricts the food that contains phenylalanine; newborn babies can be fed with breast milk.
They also require to have a special formula called lofenalac (5). The solids foods that can be
consumed by a child are:

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 Eggs
 Nuts
 Cheese
 Beans
 Milk
 Chicken
 Pork
 Beef
In order to ensure they receive a sufficient amount of proteins, the child having the
disorder require consuming the formula of PKU. It consists of all the amino acids that the
body requires except for phenylalanine.
Medication
The FDA approved that sapropterin can be consumed for the treatment of PKU. It
assists in order to lower the levels of Phenylalanine. This medicine must be utilised in
integration with a plan of meal of PKU that is special (6).
Pregnancy and PKU
Woman diagnosed with PKU can have complication risk that includes miscarriage, if they
do not follow a meal plan of PKU during their years of pregnancy. There can be a chance that
the unborn baby will be bared to phenylalanine (7). The problems in the baby include the
following:
 Heart defects
 Delay in growth
 Low birth weight
 Small head

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 Intellectual disabilities
These signs cannot be noticed immediately in the infants, but a doctor will conduct tests
in order to check for any signs of concern that the child can have
Prevention of PKU
PKU is a condition of genes and it cannot be prevented. However, an assay of
enzymes can be done. An assay of enzymes is a blood test that can decide if someone is
carrying the gene that is defective that causes PKU. The test can also be performed during the
time of pregnancy in order to screen the unborn for PKU (8). The symptoms of PKU can be
prevented by following a special diet.

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References
1. Nutriton Flashcards | Quizlet [Internet]. Quizlet. 2020 [cited 7 April 2020]. Available
from: https://quizlet.com/264587429/nutriton-flash-cards/
2. Phenylketonuria (PKU) - Symptoms and causes [Internet]. Mayo Clinic. 2020 [cited 7
April 2020]. Available from:
https://www.mayoclinic.org/diseases-conditions/phenylketonuria/symptoms-causes/syc-
20376302
3. Phenylketonuria, PKU Causes, Symptoms, Testing, Diet & Stats [Internet]. MedicineNet.
2020 [cited 7 April 2020]. Available from:
https://www.medicinenet.com/phenylketonuria/article.htm
4. Phenylketonuria: Causes, Symptoms, and Diagnosis [Internet]. Healthline. 2020 [cited 7
April 2020]. Available from: https://www.healthline.com/health/phenylketonuria
5. Phenylketonuria | PKU | MedlinePlus [Internet]. Medlineplus.gov. 2020 [cited 7 April
2020]. Available from: https://medlineplus.gov/phenylketonuria.html
6. Phenylketonuria [Internet]. nhs.uk. 2020 [cited 7 April 2020]. Available from:
https://www.nhs.uk/conditions/Phenylketonuria/
7. Phenylketonuria - NORD (National Organization for Rare Disorders) [Internet]. NORD
(National Organization for Rare Disorders). 2020 [cited 7 April 2020]. Available from:
https://rarediseases.org/rare-diseases/phenylketonuria/
8. Phenylketonuria: Symptoms, tests, and treatment [Internet]. Medicalnewstoday.com.
2020 [cited 7 April 2020]. Available from:
https://www.medicalnewstoday.com/articles/317963