PKU (Phenylketonuria)


Living with PKU

Phenylketonuria, or PKU, is a rare genetic disorder that affects a person’s metabolism. If untreated, PKU results in permanent brain damage. Screening for PKU takes place for all newborn babies in the Republic of Ireland, and across the UK and Europe. In Ireland approximately 1 in every 4,500 babies is diagnosed with PKU – a relatively high incidence rate, compared to the UK where it is believed to be closer to 1 in every 12,000 babies.

People with PKU are unable to break down an amino acid called phenylalanine (phe). This is a natural substance found in food; a building block of protein, but in people with PKU, phe builds up in the blood and in the brain and can cause serious problems.

While there is no cure for PKU, there is a way to prevent the build up of phe in the blood and brain. This involves a very challenging, highly restricted, low protein diet.

Children and adults with PKU also need to take regular dietary supplements that contain essential amino acids, vitamins and minerals, while keeping the blood phe level within a specific target range.

A PKU child’s phe level is measured regularly by blood tests that are sent to the Children’s University Hospital at Temple Street. Once analyzed, dietitians at The National Centre for Inherited Metabolic Disorders will inform patients/parents how to manage their diet in the following period.

Adults with PKU should also undertake regular blood testing to ensure they avoid any symptoms associated with high blood phe levels.


The impact of PKU

Living with PKU is a constant daily challenge.  Since the natural progression of PKU is so severe, patients and their carers must take their condition seriously.

The PKU low-protein diet has been a major success. It has prevented generations of people from developing acute mental and physical disabilities as a result of their condition. However, it is a punishing and sometimes very difficult diet to stick to, can severely affect a person’s quality of life and can have long-term health consequences.

The PKU diet is expensive.

For example, a low protein bread supplement is at least 4 times the cost of a normal loaf of bread.

The life-long low protein PKU diet is very restrictive.

The diet means food like meat, fish, poultry, cheese, milk, bread, chips, pasta, yoghurt, chocolate – things we all take for granted, are things both children and adults with PKU either can not have or can only have in very small measured quantities.

The PKU diet requires taking daily protein supplements in the form of tablets or a drink.

Many children struggle with their protein drink due to its taste and side effects.

PKU can have a lasting impact on health with widespread physical, emotional and behavioural consequences.

Some PKU people will find their diet leaves them hungry, unsatisfied and poorly nourished.

With such a restricted diet, people are believed to be at higher risk of suffering from attention deficit disorders, poor concentration and low energy levels. These in turn can affect performance at school or work.

The diet may also be associated with an increased risk of obesity. Much more research is needed in this area, but it is clear that effective PKU management includes monitoring nutritional status and preventing obesity.

In the longer term, it is believed that even amongst those who have maintained a strict PKU diet, there may be significant health impacts such as neurocognitive deficits or neurological side effects.

PKU Food pyramid

click image to enlarge

Recent News

Cyber attack on HSE.

Wenesday 19th May 2021: Message from Metabolic Unit, Temple St : Kuvan PPN High-tech drug prescriptions including Kuvan are being affected by the cyber attack on the HSE. The normal…

Continue Reading