Luxembourg's royal family is mourning the loss of Prince Frederik, who passed away on March 1, 2025, in Paris, France.
Prince Frederik, 22, was the youngest son of Prince Robert of Luxembourg and Princess Julie of Nassau.
The young royal succumbed to a rare genetic condition called POLG Mitochondrial disease.
Read: Gene Hackman and wife cause of death revealed
“It is with a very heavy heart that my wife and I would like to inform you of the passing of our son,” Robert shared via the POLG Foundation website.
According to Robert, the young prince spoke with family members on February 28 to say goodbye.
"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," recalled Robert.
"Even in his last moments, his humour, and his boundless compassion, compelled him to leave us with one last laugh….to cheer us all up."
What is POLG Mitochondrial disease?
According to umdf.org, POLG mitochondrial disease is a genetic disorder caused by mutations in the POLG gene.
This gene produces a protein that plays a vital role in copying and repairing mitochondrial DNA.
When the gene doesn’t function properly, the body struggles to produce energy, which can affect multiple organs, particularly the brain, nerves, muscles, and liver.
Its general symptoms include poor muscle tone, developmental delay, movement disorder, weakness of the limbs, vision loss, seizures, and liver dysfunction.
There is no available cure for POLG mitochondrial disease, and patients are given medications and therapy to help manage their condition.
Read: Angel Locsin's father, Angel Colmenares, passes away at 98
DIAGNOSED WITH RARE DISEASE AT AGE 14
Prince Frederik had been dealing with POLG Mitochondrial for years.
He was diagnosed with the disorder at age 14 after exhibiting symptoms.
The diagnosis came when the progression of his disease had become more acute, his father confided.
"Because POLG disease causes such a wide range of symptoms and affects so many different organ systems, it is very difficult to diagnose and has no treatments much less a cure," said Robert.
Frederik's condition inspired him to put up the POLG Foundation to offer support to those who suffer from the same condition and their families.
Robert described the disease as the battle and burden that his son had to endure throughout his young life.
"He always did so with grace and with humour," remarked Robert.
One heartfelt moment from their final conversation stayed with Robert.
"Papa, are you proud of me?" Robert recalled Frederik asking him.
"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."
Continued Robert, “The answer was very easy, and he had heard it oh so many times…. but at this time, he needed reassurance that he had contributed all that he possibly could in his short and beautiful existence and that he could now finally move on.”