[A case of stiff-limb syndrome with anti-glycine receptor antibody]

A 48-year-old woman with a 3-month history of spontaneously resolving stiff leg symptom at the age of 43 years presented with progressive onset of leg rigidity, walking difficulty, and myoclonic jerks. On admission she had marked stiffness in her foot joints with symmetric sustained dorsiflexion of the ankles and toes, with spontaneous and reflex myoclonic jerks easily provoked by knee tendon tap. She appeared to have a spastic gait due to stiffness in her legs. Needle electromyogram (EMG) examination revealed continuous motor unit activity in the tibialis anterior muscle at rest even when voluntary contraction of the gastrocnemius muscle was instructed, but no myokimic discharge or acute denervation sign was seen. The laboratory tests were unremarkable, including glutamic acid decarboxylase antibody. Cerebrospinal fluid (CSF) examination was also normal, without oligoclonal bands or elevated IgG index. She was diagnosed with stiff-limb syndrome based on neurologic examination and needle EMG findings, and she was treated with intravenous high-dose methylprednisolone (500 mg/day, 3 days), resulting in marked improvement in her symptoms. Anti-glycine receptor antibodies were subsequently identified in her archived serum and CSF obtained before immunotherapy. She was then started on oral prednisolone (30 mg/day) and had been free of symptoms.