Doctors have made a potentially significant breakthrough in the hunt for a treatment for stiff person syndrome, the autoimmune condition which affects the singer Céline Dion .

Stiff person syndrome (SPS) is a rare disease that attacks the central nervous system and can cause devastating rigidity throughout the body and painful muscle spasms. Despite decades of research, there is no cure.

Now a team of neurologists in the US trialling a novel form of immunotherapy have reported “exciting” and “very encouraging” results: the treatment has prompted dramatic improvements in people living with SPS.

Patients who previously needed help with basic daily tasks and struggled to walk have regained their ability to take part in everyday life, with some even returning to work and resuming hobbies, according to doctors at the Mayo Clinic.

The novel treatment, CAR-T cell therapy, is already used to treat cancer, and reprogrammes a patient’s immune cells to help fight disease.…