Transcript Phenylketonuria (PKU)

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PKU is an autosomal
recessive trait
Both parents must be
carriers of the trait for
the child to show
symptoms
If both parents are
carriers, the child has
a 25% chance of
having the disease
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PKU is caused by a
mutation of a gene
on chromosome 12
This gene is
responsible for
coding for the
protein
phenylalanine
hydroxylase (PAH)
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PAH is necessary for
turning the amino
acid phenylalanine
into the amino acid
tyrosine
In people with PKU,
this does not happen
and phenylalanine
builds up in the body
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The phenylalanine
stored up in the
body causes
damage to the
central nervous
system
This can lead to
moderate to severe
mental retardation
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If PKU is not detected
early, the symptoms
are severe and
irreversible
These symptoms
include seizures,
hyperactivity,
vomiting, moderate to
severe mental
retardation, and light
coloring
If the disease is caught
early, symptoms may
never occur
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PKU tends to be more common in
people of Turkish, Yemenite Jewish,
northern and eastern European, Italian,
and Chinese descent
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PKU can be detected
at birth before there
are any symptoms
Hospitals routinely
screen newborns to
check if they have the
disease
The test indicates
elevated levels of
phenylpyruvic acid in
the blood
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Treatment for PKU
involves following a
specific diet
Foods with protein
contain
phenylalanine so
cannot be eaten
The best foods for
people with PKU are
fruits and vegetables
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There is a special
formula for people
with PKU
This formula contains
protein and other
vitamins and
minerals but no
phenylalanine
This is the most
important part of the
diet