Phenylketonuria (PKU)

Phenylketonuria (PKU) is a health condition that affects children from birth.

People affected by PKU are unable to break down specific proteins within food, resulting in a build up of proteins. PKU is an inherited genetic disorder where both parents have the recessive gene.

Approximately 1600 Australians are affected by PKU.

What is Phenylketonuria

Phenylketonuria (PKU) is a metabolic genetic condition caused by a variation in the gene phenylalanine hydroxylase (PAH). The PAH gene creates an enzyme needed to process the amino acid phenylalanine (phe).

Phe is found in foods containing protein, in a non-affected individual, Phe is broken down by this enzyme. Individuals with PKU, do not produce this enzyme and are unable to break down these proteins.

When you cannot break down these proteins an excess begins to build up causing damage to the brain.

Symptoms of Phenylketonuria

PKU is screened in all newborn babies and is treated early in those who have it. Meaning symptoms are rare to occur in people who have PKU. However, when those with PKU eat a regular diet that includes proteins, phe can build up overtime. High levels of phe can results in severe symptoms such as:

• Cell damage within the brain
• Severe brain damage
• Physical and intellectual developmental delays (in those still maturing)
• Irreversible intellectual disabilities
• Seizures
• Behavioural abnormalities.

Treatment and Support

Early diagnosis, lifelong treatment and ongoing support are essential for preventing the damages associated with untreated PKU. Treatment options include:

• Lifetime diet consisting of low-protein foods and limited phe
• Nutritional supplement
• Medication
• Enzyme replacement therapy

Diagnosis of Phenylketonuria

Screening for PKU is conducted on newborns around 5 days old through blood spot screening. Using a heel prick, blood drops are collected to test the amount of Phe found within the blood sample. Early diagnosis of PKU is important for increasing a child's quality of life and managing the progression of symptoms.

Prospective parents can undertake carrier screening testing to determine if they carry the condition, this can be conducted by cheek swab testing.

For more information, head to https://mdda.org.au/.