Doctor reveals cause of Celine Dion’s on-camera spasm after singer gives inside look into her struggle with extremely rare stiff person syndrome

Stiff person syndrome is caused by a turbocharged immune system reaction that attacks the body’s own cells. Specifically, the immune system attacks cells that regulate motor neurons. Stiff person syndrome is caused by a turbocharged immune system reaction that attacks the body’s own cells. Specifically, the immune system attacks cells that regulate motor neurons.