Stiff-person syndrome
Stiff-person syndrome is a rare neurological condition in which the muscles of the torso, arms and legs become stiff, and noise, touch or emotional distress can set off painful spasms. It is thought to be autoimmune — the immune system attacking healthy cells by mistake — and it is progressive, meaning it gets worse over time. It can affect one part of the body or spread widely. Over time some people develop a hunched posture, and some become unable to walk safely because spasms and unreliable reflexes cause falls. Many become afraid to go out, because something as ordinary as a car horn can trigger a spasm. It affects about twice as many women as men, and usually begins between 20 and 60, most often in someone's thirties or forties.
This is a plain summary, not medical advice, and it is not a substitute for talking to your GP or your clinical team. For NHS information about stiff-person syndrome, speak to your GP or call NHS 111.
People who have talked about it
1 story, each one written in our own words from what the person said publicly themselves.

Céline Dion
Céline Dion on the condition she says will always be with her
Céline Dion told Vogue France about living with stiff-person syndrome, the rare neurological condition she announced she had been diagnosed with in 2022. It affects roughly one person in a million and causes muscles to go rigid. She was direct about where she is with it. She has not beaten it, she said — it is still within her and always will be. She hopes research will one day find a cure, but for now she has to learn to live with it. Five days a week she has athletic, physical and vocal therapy. She has said she had been dealing with problems with her health for a long time before the diagnosis, and that facing them has been really difficult. When she announced it in 2022 she said the spasms affected every aspect of her daily life, and stopped her using her vocal cords to sing the way she was used to. She postponed her Las Vegas residency and her tour, and has not performed a full show since 2019. In February she made an emotional return to a stage, walking out with her eldest son beside her. Asked whether she would perform again, she would not put a date on it. Her body would tell her, she said — but she does not want to simply wait. Nothing here is medical advice.
Photographs, in order: Céline Dion by Georges Biard (CC BY-SA 3.0).