She has been told that eventually she may need to amputate her legs. She's already considering how she will live her life then and has even thought about entering the London Marathon as a wheelchair racer.
"I'd love to do that," Sellars said, "and hopefully then be able to wheel myself and train hard enough to be able to do that, and raise money for charity that's helped me."
For more information on Proteus syndrome, click here.