Stiff Person Syndrome: Current and Emerging Treatments

Abstract

Stiff Person Syndrome (SPS) is a rare autoimmune neurological disorder that causes muscle spasms and progressive muscle rigidity and stiffness. People with SPS develop antibodies that inhibit glutamic acid decarboxylase (GAD), an enzyme that helps produce the inhibitory neurotransmitter gamma-aminobutyric acid (GABA). Inhibition of GAD leads to impaired synthesis and release of GABA, which causes stiffness and spasticity. SPS primarily affects the lower extremities and axial muscles, but depending on the disease's progression or subtype, other areas such as the arms or extraocular muscles may be affected. SPS is relatively uncommon, only affecting about one in a million people. Like other autoimmune diseases, it mostly affects women. Treatment of SPS includes drugs like benzodiazepines, baclofen, and rituximab or therapies like intravenous immunoglobulin or plasma exchange. Despite advancements in diagnosis and treatment, there is still no clear protocol for treatment for SPS, and disease management remains challenging for physicians. The purpose of this research paper is to provide an overview of SPS, review current treatment guidelines, and report on novel and emerging therapies.