What is stiff person syndrome, the condition Celine Dion is battling?

Singer Celine Dion has postponed her "Courage World Tour" dates through 2024 due to complications from stiff person syndrome,

A rare neurological ailment that causes spasms and muscle rigidity, the celebrity announced on Friday.

On September 18, 2019, Canadian artist Celine Dion takes the stage at the Videotron Center in Quebec City, Quebec, to kick off her brand-new global tour, "Courage.

Celine Dion cancels planned gigs and "will probably never tour again," according to a source. Dion postponed a number of events in December after discovering the cause of her  

muscle pain and mobility issues. At the time, Dion stated, "While we're still studying about this uncommon ailment,

She receives physical treatment every day, but "she is in a lot of pain," a source close to Dion told CNN.

I'm very sorry to disappoint all of you once again, Dion is quoted as saying in the Instagram post announcing the tour's cancellation. 

Even when you're 100% healthy, touring can be really challenging, so I'm working extremely hard to regain my strength.