Phenylketonuria (PKU) is a condition in which the body is unable to process an amino acid found in certain proteins. The amino acid, phenylalanine, is found in high-protein foods. PKU is rare, but babies are regularly screened for it at birth as part of the heel prick tests because any exposure to phenylalanine in a child with PKU can cause serious health problems.

What causes phenylketonuria?

PKU is genetic. Kids must inherit the defective gene from both parents in order to develop PKU. In kids with phenylketonuria, the amino acid, phenylalanine builds up in the blood and tissues because the body can’t get rid of it.

Is it serious?

Phenylketonuria can lead to brain damage, mental retardation, behavioral problems, and seizures.

Can I prevent it?

PKU is not preventable. If you have a family history of PKU, you may want to consult a genetic counsellor before becoming pregnant.

How do I know if my child has PKU?

Hospitals in New Zealand routinely screen for phenylketonuria with a heel prick test. Kids with PKU may display the following symptoms:

• Mental retardation
• Behavioural or social problems
• Seizures
• Hyperactivity
• Stunted growth
• Skin rashes (eczema)
• Small head size (microcephaly)

How do I treat phenylketonuria?

PKU is treated by avoiding exposure to phenylalanine. Phenylalanine is found in protein-rich foods like milk, cheese, nuts, eggs, chocolate, soybeans, and meats. Other dietary sources of phenylalanine include sugar free products that contain artificial sweeteners made with phenylalanine.

Should I call the doctor?

Your doctor will let you know if your baby’s screening indicates he has PKU. She will advise you as to your treatment options and possibly refer you to a dietitian who can help you understand the special dietary needs of your child.

What you need to know about phenylketonuria

• Phenylketonuria is also called PKU.
• PKU is the body’s inability to process an amino acid called phenylalanine.
• New Zealand babies are routinely screened for PKU at birth.
• PKU can cause mental retardation.
• PKU requires special dietary restrictions for life.