Medical Q&As

Phenylketonuria (PKU) - explain?

My newborn baby was diagnosed with PKU syndrome after the heel prick test? Can you explain the syndrome, give details on dealing with PKU and provide the address of any contact groups who deal with this syndrome?

Phenylketonuria (PKU) is a genetic disorder that prevents the normal processing of protein foods. PKU is more common in Ireland than in the rest of Europe. It occurs with a frequency of between 1 in 4,500 births in Ireland and 1 in 10.000 in most of Europe. Babies born with PKU lack a particular enzyme called phenylalanine hydroxylase. This enzyme is located in the liver and if it is absent the child cannot metabolise phenylalanine, which is an essential amino acid. The absence of the enzyme leads to an accumulation of phenylalanine in the blood. High levels of phenylalanine are toxic to the brain and other nerve tissue. Once the condition is identified it is important for the baby to consume a low phenylalanine diet in order to prevent the onset of brain damage. Prior to the identification of the disorder and the invention of the heel prick test many babies with PKU became severely mentally retarded. Therefore strict adherence to the special diet is the cornerstone of management and ensures that the child grows and develops without intellectual impairment. I have been unable to locate any Irish website devoted to this syndrome but you might find the following UK based site helpful: There is also a European website devoted to this topic, which is located at: You will be able to obtain more detailed information regarding dietary management of the condition through these sites and their sister sites which can be accessed through their links pages.