Canadian singer Celine Dion has lost control of her muscles, according to her elder sister Claudette. After cancelling her world tour a year ago, Claudette, 74, said that returning to the stage could take a long time after her battle with a neurological disorder called stiff-person syndrome, adding that she is working hard but has lost control of her muscles. Dion revealed her diagnosis for the first time in December 2022 via a moving post on Instagram, and months later cancelled her world tour, which was scheduled to begin at the end of 2023. In September, a video appeared on YouTube entitled "Celine Dion's Family Reveals How She Is Dying," in which she said her incurable illness was "progressing rapidly". However, Claudette denied these claims and said that she wasn't depressed at all, but she lost control of her muscles. She added that people had lost hope because the disease is not well known, receiving many support messages for the star, who is still fighting her illness. Stiff-person syndrome is a rare condition that causes an attack on the body's nerve cells and affects movement. Although research is ongoing, its rarity means that progress has been slow. It is thought that the condition, which affects only one in a million people, can also lead to spasms strong enough to break bones.