 "What is the rare genetic disorder that claimed Luxembourg prince’s life at 22?")
Prince Frederik of Luxembourg, son of Prince Robert of Luxembourg and Princess Julie of Nassau, passed away on March 1, 2025, in Paris after a prolonged battle with POLG mitochondrial disease, a rare and incurable genetic disorder.
The POLG Foundation, an organisation Frederik himself founded in 2022, confirmed the news of his passing. He was 22 years old and died a day after Rare Disease Day
In a statement released on the foundation’s website, Prince Robert wrote, “It is with a very heavy heart that my wife and I would like to inform you of the passing of our son, The POLG Foundation Founder and Creative Director, Frederik.”
“After gifting each of us with our farewells — some kind, some wise, some instructive — in true Frederik fashion, he left us collectively with a final long-standing family joke,” Robert shared.
Frederik also turned to his father during his final moments and asked, “Papa, are you proud of me?”
“He had barely been able to speak for several days, so the clarity of these words was as surprising as the weight of the moment was profound,” his father noted.
The statement from the family read, “Though one light was extinguished in Paris on March 1, so many others remain, thanks to Frederik’s selfless work.”
What is POLG mitochondrial disease?
POLG mitochondrial disease, caused by a mutation in the POLG gene, is a rare genetic disorder that progressively deteriorates the body’s cellular energy production, ultimately causing multiple organ failure.
The disease is likened to having a faulty battery that never fully recharges, gradually depleting the body’s capacity to function.
The disorder affects the mitochondria, which are responsible for generating energy within the body’s cells. When the POLG gene — responsible for mitochondrial DNA replication — is mutated, the mitochondria fail to produce enough energy to sustain critical bodily functions, affecting the brain, nerves, muscles, liver, and other vital organs.
POLG disease presents a wide range of symptoms, varying in severity and age of onset.
In Frederik’s case, he was diagnosed at the age of 14 after his symptoms became more pronounced. According to the statement, “The progression of his disease had become more acute by that time, and it had begun to affect multiple organs.”
Medical experts state that POLG mitochondrial disease has no known cure or effective treatment to halt its progression.
Its symptoms may include seizures, muscle weakness, liver dysfunction, visual impairment, and progressive neurological decline. Over time, it leads to multi-organ failure, often resulting in a shortened lifespan.
Why is POLG disease so difficult to treat?
One of the greatest challenges in treating POLG mitochondrial disease is its complex and multi-systemic impact. The disorder can affect almost any organ in the body — including the brain, muscles, liver, and intestines — and may present differently in each patient.
This variability makes early diagnosis extremely difficult, often resulting in late-stage identification of the condition.
The condition can manifest through symptoms like epileptic seizures, visual loss, liver dysfunction, motor impairment, and progressive muscle weakness. In some cases, it also leads to hearing loss, speech impairment, and eventual respiratory failure.
Experts note that over 200 mutations have been identified in the POLG gene, each producing a different set of symptoms and disease severity. This makes it extremely challenging for medical practitioners to create a universal treatment plan.
Additionally, no approved therapy exists to reverse or halt the progression of the disorder, leaving patients like Frederik to face progressive organ failure.
Research indicates that mitochondrial disorders, including POLG disease, affect approximately 1 in 5,000 people worldwide, making it the second most commonly diagnosed serious genetic disorder after cystic fibrosis.
However, due to its complexity and varying presentations, the disorder often goes undiagnosed or misdiagnosed for years.
What do we know about Frederik’s efforts to find a cure?
Despite living with a terminal illness, Frederik dedicated much of his life to advancing research and raising awareness for POLG mitochondrial disease. In 2022, he established The POLG Foundation, an organisation aimed at accelerating research, developing treatments, and eventually finding a cure for the condition.
Robert wrote in his statement, “Frederik jumped at the opportunity to create a foundation to find a cure. Though he always made it very clear that he did not want this dreadful disease to define him, he nonetheless immediately identified with and helped define the mission of The POLG Foundation.”
The foundation noted that Frederik personally took part in clinical trials, hoping that his contribution could pave the way for new treatments.
He also collaborated with scientific researchers across Europe and the United States, allowing the development of experimental cell models that could help find breakthroughs for POLG-related disorders.
A key project that Frederik championed was the creation of a MITO clothing line, which raised funds to support POLG research. Prominent fashion designer Donna Karan encouraged the initiative, with Frederik remaining deeply involved in its creative direction until his final days.
The royal family also announced that The POLG Foundation will continue its work in Frederik’s honour, focusing on funding research for mitochondrial diseases and helping other families suffering from similar genetic conditions.
Robert pledged his family’s ongoing support, stating, “We will be resolutely focused on alleviating suffering for the POLG community and other conditions associated with mitochondrial diseases.”
“Frederik knows that he is my superhero, as he is to all of our family and to so very many good friends. His superpower was his ability to inspire and lead by example,” Robert wrote in his farewell note.
With inputs from agencies
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