Understanding PolG; the disease that haunted Luxembourg’s Prince Frederik of Nassau

Even in grief, the family of Luxembourg’s late Prince Frederik of Nassau have vowed to continue fighting to understand more about the rare and devastating disease that struck down their son

Prince Frederik of Luxembourg, who has died, with his beloved dog Mushu.

In a moving post, the family of Luxembourg’s Prince Frederik of Nassau detailed his final days and how, even as he said his goodbyes, their son’s character never faded.

“Frederik’s last question to me, prior to his other remarks was: “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,” Prince Frederik’s father, Prince Robert of Luxembourg wrote in a post online.

“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.”

Prince Robert told his son that he was his “superhero”. The young prince then called his family members to his bedside so he could say one final goodbye to each of them.

Prince Frederik of Luxembourg, centre, and his family.

Prince Frederik died from a genetic disorder called PolG Mitochondrial disease. It is a serious but rare condition caused by mutations in the PolG gene. Researchers in Australia believe around one in 5000 Australian children are born with mitochondrial disease, though estimating how many people it affects globally is difficult because it is also underdiagnosed.

However, the Murdoch Children’s Research Institute indicates that 55 per cent of mitochondrial diseases could be diagnosed via a genetic blood test, a figure that rises to 71 per cent among children.

Part of the difficulty with diagnosis is the nature of the disease’s symptoms; they can vary significantly from patient to patient and include muscle weakness, eye conditions, nerve problems, liver failure, heart problems and neurological issues. It is also a progressive disease. Even in Prince Frederik’s case, he was not diagnosed until he was 14 years old when his symptoms became stark and his disease more pronounced.

In response, his parents founded The PolG Foundation which aims to raise awareness of the condition, and champions funding to try and advance scientific research into the disease.

The PolG gene provides instructions for producing an active part of an enzyme, essential for repairing mitochondrial DNA. That DNA creates energy in cells within the body.

“PolG disease is a genetic disorder that robs the body’s cells of energy, in turn causing progressive multiple organ dysfunction and failure,” the PolG Foundation says.

“Mitochondrial disease, or mitochondrial disorder, refers to a group of disorders that affect the mitochondria, which are tiny compartments that are present in almost every cell of the body. “The mitochondria’s main function is to produce energy. More mitochondria are needed to make more energy, particularly in high-energy-demand organs such as the heart, muscles, and brain. When the number or function of mitochondria in the cell is disrupted, less energy is produced, and organ dysfunction results.”

It can be a devastating disease that leads to a poorer quality of life as it progresses and strips sufferers of the function of vital organs. As a result, poor mental wellbeing is often also associated with the disorder. There are no effective treatments and no cure.

While Prince Frederik did not want to be defined by his disease, his father says he embraced the role he could play in raising awareness of it. The young prince even created his own fashion line called MITO which raises money for the PolG Foundation and provided him with a creative outlet to express his feelings and how he saw the world.

Prince Frederick died in early March following progression of his disease. Picture: PolG Foundation

Prince Frederik was 22 when he died in Paris on March 1, one day after Rare Disease Day.

“With our Superhero’s help we hope to turn our deep grief into positive results and therewith follow his unwavering example. His ultimate message is one of hope, compassion, and resilience!” his father’s post concludes.

“We are all so very proud of you, Frederik. I am so very proud of you! We love you!”