How stiff person syndrome 'turns body to stone' as Celine Dion announces tour after diagnosis

Celine Dion has confirmed a series of comeback shows four years after being diagnosed with stiff person syndrome – here's what you need to know about the condition.

Yesterday (30 March) Dion announced on Instagram that she is performing a series of shows in Paris this September. "I'm so ready to do this," the 'My Heart Will Go On' singer said in the video.

"I'm feeling good, I'm strong, I'm feeling excited, obviously, [and] of course, a little nervous."

The announcement comes four years after she was diagnosed with stiff person syndrome, an incurable neurological disease which 'turns people into statues'.

Addressing her diagnosis in the video, the 58-year-old added: "I'm doing great, managing my health, feeling good. I'm singing again, even doing a little bit of dancing."

Stiff person syndrome explained

Stiff person syndrome (SPS) is a rare neurological disorder which leads to muscle stiffness in the torso, arms and legs.

The condition is progressive, meaning it gets worse over time, and can also cause muscle spasms and pain, which can vary in severity over time.

Dion has been open about her experience with the condition, previously sharing footage of herself suffering from a 'crisis' seizure in her Prime Video documentary.

According to John Hopkins Medicine, the most common symptoms caused by SPS muscle contractions and spasms are:

• Difficulty walking and unsteadiness on the feet
• A stiff or rigid posture
• Shortness of breath if the chest is impacted by SPS
• Chronic pain
• Greater sensitivity to noise, touch and emotional stress, which can trigger muscle spasms
• Increased anxiety and agoraphobia due to a fear of experiencing symptoms in public.
• Lack of coordination
• Speech issues

There are also various types of SPS, including partial stiff person syndrome and stiff person syndrome plus, which is a combination of classic SPS features and symptoms which suggest brainstem and/or cerebellar dysfunction.

What causes stiff person syndrome?

Current research suggests that SPS is an autoimmune condition, which is where your body mistakes healthy cells and attacks them. Patients with SPS may also suffer from another autoimmune condition.

According to Yale Medicine, SPS often occurs when the body attacks a protein called glutamic acid decarboxylase (GAD), which is responsible for making gamma-aminobutyric acid (GABA).

Yale notes that GABA is a substance which helps regulate motor neurons by decreasing their activity, and low levels of GABA can lead to them misfiring.

It's thought that around 60 to 80 percent of people with SPS have anti-GAD antibodies in their blood and cerebrospinal fluid.

Who is more likely to develop stiff person syndrome?

According to the National Institute of Neurological Disorders and Stroke, most cases of SPS are diagnosed when a person is between 20 and 60. The condition can impact any age, race or gender, but is currently understood to be twice as likely to impact women as it is men, leading to the name being altered from 'stiff man syndrome'.