What is stiff-person syndrome? Celine Dion reveals rare condition.

Celine Dion announced that she was diagnosed with a rare and incurable neurological condition known as stiff-person syndrome, and that she will cancel or postpone dozens of shows in her “Courage World Tour.”

In an emotional, five-minute Instagram video posted Thursday, Dion, 54, told fans: “I’ve been dealing with problems with my health for a long time, and it’s been really difficult for me to face these challenges and to talk about everything that I’ve been going through.”