PKU Flashcards
What are the symptoms of PKU with respect to the digestive system
o Musty smell
o Musty urine
o Musty skin
o Eczema
How does PKU affect the functioning of the digestive system
As the phenylalanine hydroxylase enzyme is not present, this means phenylalanine cannot be broken down from the nutrients we consume. As we continue to consume phenylalanine without the enzyme breaking it down, it accumulates in the digestive system. The build-up will become toxic and affect the development of the brain.
What diet modifications are required for PKU
- restrict phenylalanine
- aspartame restricted diet
- low protein diet
restrict phenylalanine
The diet for PKU consists of a phenylalanine-free medical formula and carefully measured amounts of fruits, vegetables, bread, pasta, and cereals
aspartame restricted diet
Aspartame will hydrolyse/convert into phenylalanine in the body. It can be hidden source of phenylalanine in PKU patients
low protein diet
This is done by maintaining a low protein diet that avoids high protein foods.
How does PKU affect the regulation and protection of the body
In PKU people do not have the phenylalanine gene which codes to produce phenylalanine hydroxylase, which means they cannot break down the phenylalanine protein into amino acids to be absorbed as nutrients into the body. The build of phenylalanine will block neurotransmitters meaning memories cannot be formed. The phenylalanine proteins will leave from the digestive system and enter the bloodstream and be spread across the body. They will build up in the nervous tissues and others.
inheritance patterns
PKU is an autosomal recessive disease, caused by mutations in both alleles of the gene for phenylalanine hydroxylase. Both parents carry a single copy of this recessive genotype, however, do not phenotypically display it.
genetic cause
PKU is caused by a change in the phenylalanine hydroxylase gene. This enzyme converts the amino acid phenylalanine to tyrosine. If this enzyme is not present, then phenylalanine will accumulate into the blood stream and become toxic. The toxicity will damage the growing brain causing epileptic seizures.
Occurrence of the allele in the Australian population
1 in 10,000 people in Australia have PKU
Rate of occurrence of PKU in newborns in Australia
1 in 10,000 babies are born with PKU
Survival rates past and present
It does not affect life expectancy
Find the treatments applied to PKU
- retict phenylalanine
- aspartame resitiected diet
- low protein diet
- PKU formula
restrict phenylalanine
The diet for PKU consists of a phenylalanine-free medical formula and carefully measured amounts of fruits, vegetables, bread, pasta, and cereals.
aspartame restricted diet
Aspartame will hydrolyse/convert into phenylalanine in the body. It can be hidden source of phenylalanine in PKU patients.
low protein diet
This is done by maintaining a low protein diet that avoids high protein foods.
PKU formula
a special nutritional supplement for life to make sure that you get enough essential protein (without phenylalanine) and nutrients that are essential for growth and general health.
Search for community support groups that help families with members with PKU
PKU Association of NSW
- Provide food and nutritional advice
- Plan community events to help get PKU patients involved
What tests can be done to identify sufferers and carriers of PKU
- newborn screening
- blood test
newborn screening
A heel prick test can be carried out on the newborn baby. This is a blood test that analyses the baby’s chromosomes and DNA. It measures phenylalanine in blood.
blood test
Blood tests will be used to diagnose adult patients. This test involves taking a sample of blood and analysing it for the presence of the enzyme needed to break down phenylalanine.
