FAQs

Below are some regularly answered questions in relation to PKU.

What is PKU?

PKU is a rare metabolic disorder in which the body is unable to break down protein in food. This metabolic disorder is a result of the liver being unable to produce an enzyme called phenylalanine hydroxylase. This breaks down an amino acid called phenylalanine. Phenylalanine is one of the amino acids that are present in all protein in our food. In persons with PKU, phenylalanine accumulates in the blood because their cells are unable to convert phenylalanine to tyrosine. This excess, left untreated by diet, can retard physical and intellectual development of the brain.

Is PKU an inherited disease?

Yes, the person with PKU has inherited the defective gene from both parents and only occurs when both parents carry this gene, even then, the chances of it being passed on are one in four.

How is PKU treated?

PKU is treated effectively with a low protein diet plus a supplement to provide tyrosine and extra vitamins and minerals that would be insufficient from the diet alone. This diet is recommended for life and very restrictive on the food and quantities permitted. In fact, people with PKU are unable to eat meat, fish, poultry, nuts, cheese, bread, pasta, eggs, ice cream and dairy products.

How long must my child be on the dietary restrictions?

Current research indicates that the diet should be continued for life.

Will my child grow out of PKU?

No, tolerance does not change as we grow up. It was originally thought that the diet would cease when the brain was developed but it has since been shown that phenylalanine still has a significant effect on the central nervous system of PKU teenagers and adults.

How will I know whether my child Phenylalanine "Phe" levels are high?

Our blood levels need to be closely monitored through a home blood test which needs to be sent to the screening laboratory for results.

How long does it have to be before my child is affected by the high levels of Phenylalanine in their system?

If phenylalanine levels remain too high for a long time, the damage to the brain is severe and irreversible. The effects of PKU can be prevented if a low protein diet is started immediately and continued throughout life.