(NEXSTAR) – Celine Dion revealed to her fans Thursday she has been diagnosed with stiff-person syndrome, a rare neurological disorder that affects about 1 or 2 people per million, according to Johns Hopkins Medicine.

The disease “is characterized by fluctuating muscle rigidity in the trunk and limbs and a heightened sensitivity to stimuli such as noise, touch, and emotional distress, which can set off muscle spasms,” according to the National Institute of Neurological Disorders and Stroke (NINDS).

People with stiff-person syndrome often have a hunched-over or stiff posture, and may have trouble walking or moving. Some people may be “afraid to leave the house because street noises, such as the sound of a horn, can trigger spasms and falls,” NINDS explains.

Without “normal defensive reflexes,” people with stiff-person syndrome often suffer falls, and can injure themselves easily.

Choking back tears, Dion said her condition is forcing her to postpone shows scheduled for spring 2023.

“I wasn’t ready to say anything before, but I’m ready now. 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,” the Canadian singer said before revealing her diagnosis. “We now know this is what’s been causing all of the spasms that I’ve been having.”

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Dion said the spasms affect “every aspect” of her life, making it hard for her to walk and even sing. “I always give 100% when I do my shows, but my condition is not allowing me to give you that right now,” she said.

The syndrome occurs about twice as often in women as in men, according to NINDS, though occurs in very small numbers overall. The cause isn’t yet understood, but research suggests it may be an autoimmune issue in the brain and spinal cord.

NINDS says the rare condition is often misdiagnosed as Parkinson’s or multiple sclerosis, among other diseases.

It can be treated with intravenous immunoglobulin (IVIg), muscle relaxants and pain relievers, but there is no known cure.

“I have to admit it’s been a struggle,” Dion said. “All I know is that singing is what I’ve done all my life and it’s what I love to do the most.”

The singer concluded by saying she plans to concentrate fully on her health and recuperation, and hopes to be back on stage performing soon.