(NewsNation) — Celine Dion’s sister, Claudette, says the singer has lost control of her muscles a little more than a year after being diagnosed with stiff-person syndrome.

Speaking to Canadian media outlet 7 Jours, Claudette Dion said her sister wants to “return to the stage.”

“In which state? I do not know. The vocal cords are muscles, and the heart is also a muscle,” Claudette Dion said.

Claudette Dion told 7 Jours her sibling has “always been disciplined.”

“She works hard, but she doesn’t have control of her muscles,” Claudette Dion said.

Amid the famous singer’s health challenges, she has also found support. Many have called the family’s charity Fondation Maman Dion, Claudette Dion said.

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“People tell us they love her and pray for her. She receives so many messages, gifts, blessed crucifixes,” Claudette Dion said.

Celine Dion announced her stiff-person syndrome diagnosis in December 2022. In Instagram videos posted in French and English, Celine Dion said the spasms she was experiencing affected her ability to walk and sing.

This caused her to postpone, then ultimately cancel, her Courage world tour.

“I miss seeing all of you, being on the stage, performing for you. I always give 100% when I do my shows, but my condition is not allowing me to give you that right now,” Celine Dion said last year.

During another interview this past August with Hello! Claudette Dion described the spasms her sister was experiencing.

“They’re impossible to control. You know how people often jump up in the night because of a cramp in the leg or the calf? It’s a bit like that, but in all muscles,” Claudette Dion said, adding “There’s little we can do to support her, to alleviate her pain.”

However, Claudette Dion also said that Celine is doing “everything to recover.”

“She’s a strong woman,” Claudette Dion said.

What is stiff-person syndrome?

Stiff-person syndrome, as defined by the National Institutes of Health, is a “rare, progressive neurological disorder.” Only one or two people per 1 million are affected, according to Johns Hokins Medicine. Symptoms may include stiff muscles in the torso, arms and legs, as well as greater sensitivity to noise, touch and emotional distress that can set off muscle spasms.

People who have stiff-person syndrome can develop hunched-over postures, while some can become unable to walk or move.

Because they do not have the reflexes to catch themselves, many with stiff-person syndrome end up falling frequently, leading to serious injuries, the NIH wrote.

Symptoms of stiff-person syndrome can be managed with appropriate treatment, the NIH says. These include an anti-anxiety and muscle relaxant medication called oral diazepam, or with drugs that alleviate muscle spasms like baclofen or gabapentin.

Dr. Tom Pitts previously told NewsNation certain therapies can also help.

“If those (therapies) are successful, you would be looking at a much better quality of life,” he said.