What Is Stiff-Person Syndrome?

Celine Dion performs in London's Hyde Park.
Celine Dion performs in London's Hyde Park. / Simone Joyner/GettyImages

In early December, Celine Dion announced that she has been diagnosed with stiff-person syndrome (SPS), a progressive neurological disorder, and as a result would have to postpone her 2023 European tour dates to 2024. It’s a rare diagnosis—only about one or two out of every 1 million people have it.

For many individuals, this was the first time hearing that SPS even exists. Here’s what you need to know about the rare condition.

What is Stiff-Person Syndrome?

SPS is a neurological autoimmune disorder. People who have it get severe muscle spasms and stiff muscles in the torso, arms, and legs. For Dion, SPS is even affecting her vocal cords, which makes her unable to sing. The disorder can also lead to increased sensitivity to sound, stress, and physical contact. Sometimes, that increased sensitivity can trigger the spasms. It can get so bad that people with it can have trouble walking or become disabled.

What Causes Stiff-Person Syndrome?

Because SPS is such a rare disorder, doctors and scientists don’t know exactly what causes it. But according to Yale Medicine, researchers are getting close. One theory is that it's an autoimmune reaction attacking the body’s glutamic acid decarboxylase (GAD) protein. GAD helps make gamma-aminobutyric acid (GABA), which regulates motor neurons in the brain. If there’s less GABA, the neurons overreact, leading to the spasms.

SPS is twice as common in women than it is in men, and symptoms usually start to show between ages 30 and 60. It’s often diagnosed in conjunction with another autoimmune disorder, like type 1 diabetes, and is more common in patients with cancer.

Is SPS Treatable?

Unfortunately, SPS does not have a cure. But it is treatable with medication, immunotherapies, and some types of physical therapy. The anti-anxiety drug diazepam, an anticonvulsant medication called gabapentin, and the muscle relaxer baclofen can be used to ease the spasms and stiffness that accompany SPS, according to the National Institute of Neurological Disorders and Stroke. Intravenous medications can reduce sensitivity to noise and touch, and aqua therapy can help with muscle pain.