PKU a Metabolic Disorder - Remember the Heel Prick Test?
By Carol Duncan - 24th August 2012
image: Cayden and Zoe, no reproduction permitted.
Have you ever noticed the labels on some artificially sweetened foods which read: 'PHENYLKETONURICS: CONTAINS PHENYLALININE.'
You may have heard of PKU, or phenylketonuria, but what is it?
I recently read an article about Queensland mum, Zoe Mitter and her son Cayden, aged two. I found Zoe and Cayden's story fascinating so I gave Zoe a call because I really think the more all of us know, the more understanding and the more helpful we can be for children like Cayden when we have them at our homes or when they're visiting cafes and restaurants. Zoe says this is a really big problem in cafes, etc, as often staff feel they are doing the right thing in the foods or drinks they offer him, but sometimes seem offended when Zoe informs them that he can't eat it.
Zoe had the heel prick test done on Cayden when he was born. "It was not something which was mandatory but given to me as an option. I asked the nurse taking the blood, 'What is this exactly for?' and she told me it was for very rare conditions and that it was the test you never want to hear back from. So when I did hear back from it, it was a bit of a shock,"
"We got home from the hospital and a couple of days later I received a phone call. I was still trying to adjust to feeding and sleeping routines so it was a bit of a shock when I got the phone call and they advised me that I needed to come to the Royal Brisbane Children's Hospital as his tests had come back with some abnormal results."
I think any parent who has had to deal with illness in their child finds it an anxious time, but as the mother of a child who was born with a congenital heart condition I'd never heard of previously, I could relate to the state of shock and fear that Zoe and her family must have felt.
"Luckily, my mum was here at the time and I think I fell apart to her. I don't know how I would have coped. Of course, we went straight online and started Googling, which was a really bad thing to do as there's a lot of negative things online about PKU and the condition of people who haven't had treatment, so that was what started to scare me. Fortunately, the doctor that I spoke with said to me, 'I'm going to send you some information, please read that above anything online,' so we did sit down and read a bit more before we went to the hospital. When we arrived we were bombarded with information, but you just have to pick up and keep going."
On a positive note, Zoe says if you have to have a metabolic disorder, this is the one to have, "It's the most common, but still incredibly rare. 1 in 15,000 children in Australia are shown to have PKU so that's very rare. Those rates are a little different in other countries. But if you have to have one, the other metabolic conditions tend to have more dire results. You have to be really quite diligent. Cayden is lucky to be on the mild end of PKU so he has greater dietary options than other children with PKU or other metabolic disorders."
Whenever I interview parents of children with food intolerances or allergies, I can only really begin to understand what a constant battle it must be, and what constant vigilance must be required to ensure the right foods are adhered to. So what does Cayden's PKU mean for his diet and how does Zoe manage it?
"It means that he is unable to break down protein in his metabolism, or one particular amino acid that he is unable to break down. That means that for Cayden to consume regular proteins - meat, fish, eggs, nuts, dairy products, etc - that one particular amino acid would start to build up in his system and become toxic in his brain. He would start to behave differently, irrationally, and escalate from there becoming quite serious,"
"He can have a little bit of potato, but everything has to be measured. I have a little set of kitchen scales and everywhere we go, his food has to be measured based on the very strict guidelines we've been given. But there are free foods - a lot of fruit and vegetables are free but not strawberries or bananas."
We all want our kids to grow big, tall, strong and healthy, but for Cayden this means an extra step on top of the control of diet.
"Cayden has to consume a special protein supplement, what the rest of us would consider a protein shake, but it doesn't contain the amino acid that could harm him. He basically lives on three of those a day, it fills him up and provides him with all the nutrients he needs to grow. He's topping the height charts so they obviously work!"
Often you will see a warning on the side of artificially sweetened products that they are unsuitable for people with PKU. "Yes, contains phenylalinine - which is the one amino acid Cayden's body can't metabolise can't metabolise, so it's an absolute no-go."
And the future for this bright little boy? Zoe is extremely positive. "I have to believe that it is part of his education, I need to ensure he is well educated. His doctors and nurses are amazing and we are lucky we have such a great support team as well as the Metabolic Dietary Disorders Association, they provide us with a lot of support, so I'm hoping that with my pro-active involvement in those sorts of things that Cayden will do the right thing by himself."
There is more information here in the Human Genetics Society of Australia PKU Handbook.