A prince of Luxembourg has died at 22 of a genetic disease for which he spent his brief life raising awareness.

Prince Frederik, the second cousin of the heir to the Luxembourg throne, discovered at age 14 that he had a mutation in his POLG gene, which is involved in the replication and repair of DNA. He died on March 1 in Paris, his father, Prince Robert, said in a statement through the POLG Foundation.

Estimates vary, but roughly one in 10,000 people are thought to have POLG, or polymerase gamma, disease, according to the United Mitochondrial Disease Foundation. It is a mitochondrial disorder, a group of conditions that affect how mitochondria in cells produce energy. POLG disease affects multiple organs and can lead to seizures and poor coordination, among other symptoms.

“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 said.

POLG deficiency is a particularly brutal type of mitochondrial disease, according to Sir Doug Turnbull, an emeritus professor of neurology at Newcastle University and a member of the POLG Foundation’s scientific advisory board. “It is so relentlessly progressive,” he said, “attacking so many different systems with sadly the same conclusion.”

Prince Frederik was a founder and the creative director of the POLG Foundation. The organization used his DNA for research, initiated studies and made a short film about the disease. Frederick also designed a clothing line to raise money for research.

Frederik was born in Aix-en-Provence, France, and grew up in Switzerland. He was a fan of the American television show “The Office,” his father said, and had seen the full series 10 times.

In his last days, Frederik was in the hospital with pneumonia and another serious infection that left him unable to move, but he could still look out the window, Prince Robert said.

“Through the small, mesh-covered window, he saw the Eiffel Tower glistening with its hourly dance of lights,” his father said. Frederik asked his brother, Alexander, to take a photograph of the setting sun.

Frederik was a second cousin of Prince Guillaume, who will be taking over the throne of Luxembourg when his father, Grand Duke Henri, retires in October. Frederik and Guillaume share great-grandparents: Charlotte, Grand Duchess of Luxembourg, who reigned from 1919 to 1964, and her husband, Prince Félix.

“When you’re a kid, you have all these dreams, all these aspirations,” Frederik said in the film produced by his foundation. “I’m not sure I understood all the consequences of POLG when I first got diagnosed. It’s more subtle, where slowly the world is getting smaller and smaller.”