A PKU story | Nathan and phenylketonuria: living with an invisible disease on a daily basis
A PKU story | Nathan and phenylketonuria: living with an invisible disease on a daily basis
Disclaimer: The information presented here reflects my personal experience with phenylketonuria and my own research. It is not a substitute for professional medical advice. Always consult a healthcare professional before making any changes to your diet or beginning an exercise program.
Health Canada finally approved PTC Therapeutics’ Sephience in October 2025, a very promising treatment that has already proven itself and has the potential to improve the lives of people with phenylketonuria. But nothing is certain yet!
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There is no guarantee that it will be made available in all Canadian provinces. It is therefore essential that we share our experiences with PKU, describe our daily challenges, and, above all, explain how Sephience has the potential to significantly change our daily lives. To this end, I invited several members of the community to send me their testimonials. Today, I am sharing Catherine Héroux’s story with you.
Nathan is 9 years old. Like all children his age, he loves to play, laugh, and enjoy life. But Nathan lives with a rare disease: phenylketonuria (PKU). This inherited metabolic disorder prevents his body from properly breaking down phenylalanine, an amino acid found in proteins. To avoid a toxic buildup in his blood, he must follow an extremely strict, low-protein diet every day of his life.
Nathan can consume a maximum of 330 mg of phenylalanine per day, or about 7 grams of protein. Every food he eats must be weighed, measured, and calculated. The slightest deviation can have serious consequences for his neurological development, leading to irreversible cognitive disorders.
On paper, it may seem simple: all you have to do is count. In reality, it’s a daily struggle.
Let’s take an example: a typical breakfast for a 9-year-old child, two slices of toast with Nutella and a banana.
The bread must contain less than 1 g of protein per slice (45 mg of phenylalanine).
The banana adds 45 mg.
A tablespoon of Nutella adds 45 mg.
Result: 135 mg of phenylalanine for breakfast. That leaves him with only 195 mg for the rest of the day. That includes three meals and snacks. The margin is tiny.
Preparing meals, measuring quantities, planning menus, administering the special medical formula... all this takes up nearly 4 hours a day, or 28 hours a week, the equivalent of a part-time job.
There are many frustrations. Some days, Nathan is hungrier than usual. But once he reaches his limit, he only has a few very low-protein foods left, which are often tasteless. Temptations are everywhere: at the grocery store, at school, at friends’ parties, on Halloween, or during class celebrations. These are all moments that remind Nathan that he can’t eat like everyone else.
Beyond the diet, there is the emotional weight. Nathan often asks himself, “Why me?” He is tired of explaining his condition to justify his “different” meals. His need to be accepted, understood, and feel normal is constant.
Going on a trip with a child with PKU is a planning challenge. It’s impossible to rely on the food available at the destination: everything must be prepared in advance, weighed, and transported. Vacation time turns into management and calculation time. Spontaneity does not exist.
Fortunately, science is advancing.
A new drug, Sephience, could transform the lives of people with PKU. This treatment helps reduce blood phenylalanine levels and increases daily protein intake.
For Nathan, this would mean being able to try more foods, go to restaurants, travel more freely, and above all, live like a normal child. This drug represents not only medical hope, but also immense relief for families who spend hours preparing and calculating meals.
When Nathan learned about Sephience, his eyes lit up. For him, it is the promise of a simpler, freer life.
Sephience must become available to residents of Quebec. Every day counts for children like Nathan, who show exceptional courage and resilience. Thanks to science, they can hope for a more normal life. But for that to happen, these advances must be available to everyone.
Let’s give Nathan and all children with phenylketonuria the hope of a life without calculations, without fear, and full of freedom.
Let’s make our voices heard loud and clear
Even when treated with a low-protein diet, phenylketonuria remains a daily challenge: it affects every meal, every decision, every moment of freedom. However, Sephience offers solutions that could lighten this burden and give us back control of our lives.
If you would like to add your testimony to this campaign, please feel free to send it to me. Every story is important. Otherwise, simply share this article to spread the message.
Many thanks to Catherine Héroux for her testimony.
The challenge is real
#PKUWarrior