LUXEMBOURG — Prince Frederik of Luxembourg has died after a lifelong battle with a rare genetic disorder known as POLG mitochondrial disease.

He passed away on March 1 in Paris, his family announced on the website of the POLG Foundation, which Frederik started in 2022.

“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,” his father Prince Robert of Luxembourg wrote.

The foundation describes POLG as a “genetic mitochondrial disorder that robs the body’s cells of energy, in turn causing progressive multiple organ dysfunction and failure.”

It said the disease has no treatment or cure.

“Frederik and the POLG Foundation ... are committed to finding therapies and a cure to save other patients from suffering what Frederik and our family have endured,” his father wrote.

Despite his condition he “found the strength and the courage to say goodbye to each of us in turn – his brother, Alexander; his sister, Charlotte; me; his three cousins, Charly, Louis, and Donall; his brother-in-law, Mansour; and finally, his Aunt Charlotte and Uncle Mark,” Prince Robert wrote.

Frederik was “disciplined and organized beyond belief,” the statement said.

“On Friday [the day before he died], his Italian Duolingo and exercise alarm went off like any other day.”

Prince Frederik was diagnosed with POLG at 14, which causes such a wide range of symptoms and affects many different organ systems, making it very difficult to diagnose and has no treatments or a cure, the statement said.

“As is the case for 300 million people like Frederik worldwide, these diseases are usually hard to recognize even by physicians, and patients’ families may never know what they are suffering from as they may only be identified very late in their progression,” his father wrote.

“One might compare it to having a faulty battery that never fully recharges, is in a constant state of depletion and eventually loses power,” Prince Robert wrote.

Prince Frederik had voiced his gratitude for having his disease over the years. And it was recently found out that he once had told a close friend (unbeknown to Frederik’s family until now): “I am glad that I am the one who was born with this disease. Even though I’ll die from it .... and even if my parents do not have the time to save me, I know that they will be able to save other children.”

“Though Prince Frederik always made it very clear that he did not want the dreadful disease to define him, he devoted himself to spreading awareness on the rare disease,” the statement said, including participating in medical trials “with the goal of finding treatments and, perhaps, ways of repurposing molecules to help patients with his condition.”

“Frederik passed on March 1st 2025, in Paris France, the City of Lights. One light was extinguished, but so many remain.” — CNN