Monarch Disease Ontology entry MONDO_0008491 (stiff-person syndrome) can be described as follows. Stiff-man syndrome (SMS) is a rare neurological disorder comprising fluctuating trunk and limb stiffness, painful muscle spasms, task-specific phobia, an exaggerated startle response, and ankylosing deformities such as fixed lumbar hyperlordosis. Also known as: Moersch-Woltman syndrome, Stiff Person Syndrome, Stiff Person syndrome, Stiff man syndrome, Stiff-man syndrome, stiff man syndrome.