What is stiff person syndrome? Celine Dion reveals she has one-in-a-million condition

Celine Dion today revealed she is suffering with the one-in-a-million condition stiff person syndrome.

The progressive autoimmune and neurological disorder causes severe muscle spasms that result in people freezing up and can eventually lead to difficulty walking.

The Canadian singer, 54, tearfully told fans she would have to cancel her upcoming tour in February — but promised to continue to battle the debilitating condition.

But what exactly is it stiff person syndrome? Here we detail what causes the disorder and how doctors treat it….

What is stiff person syndrome?

Stiff person syndrome is an extremely rare disorder that makes the muscles in the torso and limbs alternate between spasming and being rigid.

Estimates suggest it affects around 70 people in the UK and 330 in the US and remains little understood. Around twice as many women as men are hit with it.

The progressive disease sees patients’ stiffness increase over time and can lead to them needing to use a wheelchair. 

There tend to be three types of the syndrome:

• Classical person man syndrome: When rigidity and spasms are around the back and stomach, and occasionally thighs and neck. It can cause back curvature over time.
• Stiff limb syndrome: Spasms especially affect the legs and feet, occasionally causing them to become fixed in place. Hands can also be affected.
• Jerking stiff person syndrome: The rarest, most aggressive form, which includes symptoms from both the others, and also affects the head and eyes.

What causes it?

Experts do not know exactly what is behind the disease. 

But they believe it may be caused by an autoimmune reaction, when the body attacks its own nerve cells that control muscle movement.

Around 40 per cent of sufferers also have type 1 diabetes, another autoimmune disease. Type 1 diabetes is particularly associated with classical person syndrome.

Other autoimmune conditions like vitiligo, which causes white patches of skin, and pernicious anemia are likewise associated with it.

It is also more common in people with breast, lung, kidney, thyroid or colon cancer, as well as lymphomas, but researchers do not yet know why. 

In stiff person syndrome, the immune system attacks a protein that helps make gamma-aminobutyric acid (GABA), which regulate motor neurons — the nerves that control movement.

Low levels of GABA cause the neurons to continuously fire when they are not supposed to, resulting in the spasms and rigidity. 

What are its symptoms? 

The main symptoms caused by stiff person syndrome are spasms and rigidity of the torso and limbs.

Spasms can be triggered by loud noises, with the condition also causing heightened sensitivity to sound.

Touch and emotional distress can also be felt more intensely as a result of the condition.

The spasms can be so severe they cause people to fall over or lead to difficulty walking and other disability.

Stress and anxiety are also usually higher in those with the condition, particularly because of the unpredictability of spasms.

The lack of GABA — which regulates anxiety — in their system also affects mental health. 

How is it diagnosed?

Because of its rarity and baffling symptoms, which are often mistaken for Parkinson’s disease or multiple sclerosis (MS), diagnosing the syndrome can take a long time.

But if doctors suspect stiff person syndrome, they can confirm it with two tests.

The first looks for antibodies to the previously mentioned protein, called glutamic acid decarboxylase (GAD), in the blood.

High levels of GAD antibodies indicate stiff person syndrome may be occurring, although levels are also elevated in people with type 1 diabetes. 

The second test is an electromyogram (EMG), which assesses the health of muscles and motor neuron. 

Doctors insert a needle directly into affected muscles and record electric activity in them.

Is there a cure? 

No. Unfortunately doctors are unable to reverse or cure the lifelong condition.

However, treatments can be given to help control symptoms in the majority of patients.

Drugs including diazepam and baclofen —which both control spasms — can help regulate episodes and reduce stiffness.

Some patients with more severe symptoms are also given therapies to manipulate their immune systems, with the aim of increasing GABA levels.

Immunoglobin transfusions can be given to affect antibody levels in the blood in some cases.

Medications such as sedatives and steroids may also be prescribed.

Meanwhile, patients are often prescribed physical and aqua therapy to improve how well their muscles work.