NIH CONFERENCE The Stiff-Person Syndrome: An Autoimmune Disorder Affecting Neurotransmission of g-Aminobutyric Acid

The stiff-person syndrome, a rare and disabling disorder, is characterized by muscle rigidity and episodic spasms that involve axial and limb musculature. Continuous contrac-tion of agonist and antagonist muscles caused by involun-tary motor-unit firing at rest are the hallmark clinical and electrophysiologic signs of the disease. Except for global muscle stiffness, results of neurologic examination are usu-ally normal. Results of conventional computed tomogra-phy and magnetic resonance imaging of the brain are also normal. The cause of the stiff-person syndrome is unknown; however, an autoimmune pathogenesis is suspected be-cause of 1) the presence of antibodies against glutamic acid decarboxylase (GAD), the rate-limiting enzyme for the synthesis of the inhibitory neurotransmitter g-aminobu