The prince had PolG disease, a genetic mitochondrial disorder that prevents the body's cells from producing adequate energy.

The filmmaker who chronicled Prince Frederik of Luxembourg’s battle with the rare genetic disorder PolG has shared her experience working with the royal, who passed away on Mar. 1 at 22. Commissioned by Frederik’s mother,

Two weeks after Prince Frederik of Luxembourg died from POLG, a documentary filmmaker has revealed that the 22-year-old struggled to "get up by himself" as he battled the rare genetic disorder in an interview with Us Weekly.