The royal family of Luxembourg is mourning the loss of PolG Foundation founder and creative director Prince Frederik, who passed away at 22. The foundation confirmed his passing on its website and revealed that he spent his last days surrounded by his family
According to the foundation, on February 28 — Rare Disease Day — Frederik spoke individually to his brother Alexander, sister Charlotte, cousins Charly, Louis, and Donall, his brother-in-law Mansour, Aunt Charlotte, and Uncle Mark. He had already shared his deepest thoughts with his mother, who had been by his side for 15 years.
Before his final farewell, he shared one last family joke. Among those final moments, his father, Prince Robert, recalled an especially emotional exchange. Frederik asked, “Papa, are you proud of me?” Robert reassured his son that he had made a profound impact in his short life.
The Royals of Luxembourg’s Instagram page expressed their grief through a message on the PolG Foundation’s Instagram account, “Words can’t describe how much pain I am feeling for Robert and Julie for losing their beloved son, Frederik.”
They described Frederik as an “inspiration” to young people, whose impact will continue to inspire others facing the same illness. They also sent thoughts and prayers to Charlotte and Alexander, acknowledging the pain of losing their younger brother. “Rest in peace, sweet Prince Frederik,” they wrote.
Following the announcement, tributes poured in, with many honoring Frederik’s courage and unwavering spirit. One netizen stated, “
a true superhero.” Another shared, “Difficult to find words to describe this loss. I am thinking of you all and sending love. Frederik was exceptional in the courageous way he lived with his illness, what an example to us all. 
”
A mourner remembered Frederik for his “charm, brilliant humor, and creative vision,” sending love in his memory. At just 14, Frederik’s world changed overnight. He went from playing football, skiing, and enjoying meals with friends to struggling to walk, stand,
Months of uncertainty followed, with misdiagnoses adding to the fear. Finally, doctors identified the cause: Mitochondrial Disease, a rare genetic disorder caused by mutations in the POLG gene.
PolG disease is often compared to a battery that never fully recharges — cells slowly lose their ability to function, causing progressive organ failure. Though considered rare, mitochondrial diseases are now believed to affect 1 in every 5,000 people worldwide, making them the second most common serious genetic disorder after cystic fibrosis.
After years in hospitals, Frederik and his family decided they couldn’t just accept the bleak outlook. They knew something had to change — not just for him, but for others facing the same disease.
Through it all, Frederik remained incredibly strong. His father reflected on the challenges his son faced. “Being confronted with such a disease at that age is, of course, incredibly tragic. All your friends start going out and exploring the world, while you are confined to your bed, losing control over your body,” Robert recounted.
Frederik eventually lost the ability to eat on his own and had to be fed through an IV. “All those pleasures that connect you to the outside world slowly disappear — it’s really tough,” he said.
Robert described Frederik as an extremely social person with a large circle of friends and was always “the life of the party, super positive and cheerful.” Given his son’s upbeat nature, he never thought he would have to worry about him. “But back then, I didn’t know where life would take us,” he recalled.
Despite the hardships Frederik faced, his resilience never wavered. “Precisely because of his strength, he was able to handle his fate as best as possible and even find something positive in his situation,” Robert added.
His siblings, Charlotte and Alexander, also struggled to process their brother’s illness. “At first, there was the initial shock, followed by deep sadness,” Robert shared. Despite the pain, they stood by Frederik every step of the way. Later, they became actively involved in the PolG Foundation, determined to continue his fight.
Research on PolG disease could help far more than just mitochondrial patients. Robert explained that mitochondria affect many parts of the body, and problems with them are linked to diseases like Parkinson’s, depression, and cancer.
Mitochondrial decline also plays a role in aging, so finding solutions for these disorders could lead to breakthroughs in treating multiple conditions.
For parents facing similar challenges, Robert acknowledged, “On a personal level, it is difficult to give universal advice. Everyone is different and processes tragedy in their own way. Compassion is important. And the awareness that every story is unique.
Robert acknowledged that, despite the hardships of Frederik’s illness, they also witnessed moments of profound compassion. During their most difficult times, the support and selflessness of others served as a powerful reminder of the goodness in people.
“The number of wonderful people we have met throughout our journey, who dedicate their lives to helping others, is incredibly humbling. It gives you hope in humanity,” he shared.
Still, the early days of Frederik’s diagnosis were overwhelming. Their world was consumed by hospital visits and medical procedures. Robert explained that their primary focus was on Frederik’s care, leaving them exhausted and emotionally drained, with little energy to research the disease. “We couldn’t focus on much else,” he admitted.
As Frederik’s condition stabilized, they began searching for more information. Their desperation led them to experts worldwide, attending biotech conferences, consulting pharmaceutical professionals, and connecting with funding organizations.
Over time, they built a network of specialists, which Robert felt should be shared with other affected families. He was surprised by the lack of collaboration in the medical field, where scientists, pharmaceutical companies, and funding organizations often work in isolation. Some even withhold findings to secure publications or protect their research.
To address this, Robert and his family founded the PolG Foundation in 2022 to foster transparency and cooperation. “Our goal was to bring a little more heart into this field and encourage people to share their knowledge to advance research for the benefit of all patients,” he explained.
According to the PolG Foundation’s Instagram page, fashion designer Donna Karan was among those who supported the cause.
However, he clarified that the foundation’s focus is on scientific research rather than direct patient support. “As a foundation, we do not focus on patient support, but there are others who specialize in this and do truly brilliant work. They helped us as parents immensely when we were grasping at every straw in search of answers,” he said.
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