GMS 6201: General Medical Biochemistry
June 17, 2018
The Culprit of Phenylketonuria: Amino Acids
Babies are indeed a bundle of joy. Unfortunately, they are susceptible to diseases and
disorders while in the womb and as soon as they are delivered. Statistics state that 1 in 10,000 -
15,000 newborns in the United States are diagnosed with Phenylketonuria (Mayo Clinic Staff),
which is better known as PKU. How the disorder is inherited, signs and symptoms, and life
expectancy are some of the topics that parent’s usually ask about. In the end, PKU is highly
treatable and the individual can expect to lead a normal life depending on their compliance with
treatment and their lifestyle; however, it can lead to death if it is not treated.
Phenylketonuria is inherited in an autosomal recessive pattern. Autosomal recessive
inheritance occurs when the individual has two copies of the altered gene. Each of the child’s
parent carries one copy of the altered gene, meaning that they are not affected by PKU nor do
they show symptoms of the disorder. A child that has the disorder, is missing a an enzyme by the
name of phenylalanine hydroxylase. This particular enzyme is necessary in catalyzing
phenylalanine in order to generate tyrosine. When the process is hindered, there is build up
phenylalanine which can cause damage to the child’s brain and significant intellectual
disabilities. The child may also have a low birth weight and and may grow at a slower rate than a
child in his/her’s age range (Lee).
A PKU test is conducted within two days of the child’s birth. To ensure accurate results,
the test is completed after the child has ingested protein in their diet. It is likely that the child will
not receive sufficient proteins and nutrients on their restricted diet alo...