Presynaptic neuromuscular transmission defect in the stiff person syndrome

BACKGROUND: The stiff person syndrome (SPS) is a rare disorder characterized by muscular rigidity and stiffness. CASE PRESENTATIONS: We describe an SPS patient presenting with longstanding fatigue and electrophysiological evidence of presynaptic neuromuscular transmission defect, who responded to administration of pyridostigmine. In contrast, no electrophysiolgical evidence of neuromuscular transmission defect was demonstrated in 2 other SPS patients without fatigue symptoms. CONCLUSIONS: Our findings suggest that glutamic acid decarboxylase (GAD) antibodies may play a role in presynaptic neuromuscular transmission defect of SPS patients with fatigue.