Objective: To describe the clinical and treatment characteristics of movement disorders associated with antibodies (Abs) against neuronal synaptic extracellular (NMDAR, LGI1, CASPR2, IgLON5, Glycine receptors (GLY-R)), intracellular (GAD65) and neuronal non-synaptic (Tr, Yo, Hu, SOX1, basal ganglia (BG)) targets from a tertiary neurology unit.
Background: Neuronal Abs are associated with an increasingly heterogeneous group of movement disorders. Although there are some characteristic associations e.g. LGI1-Abs and faciobrachial dystonic movements; there is increasing heterogeneity as testing has become more widely available. Furthermore, reported treatment regimens and response are variable.
Method: We performed a retrospective case record review of patients with neuronal Abs from 2010-20. All assays were performed by the regional UKAS accredited laboratory.
Results: Neuronal Abs were identified in 213 cases. A clinically relevant presentation (autoimmune encephalitis or paraneoplastic syndrome) was recorded in 88/213 (41%) cases. Of these, 45/88 (51%) presented with a movement disorder and more than one type was recorded in 15/45 (34%). Cerebellar ataxia (12/45; 26%) was the most common movement disorder (GAD-Ab=3, n=2; SOX-Ab, Yo-Ab, GAD65-Ab, NMDAR-Ab, n=1; Hu-Ab, Tr-Ab, BG-Ab). Orofacial dyskinesia/choreoathetosis was recorded in n/total (75%) of cases with NMDAR-Abs, faciobrachial dystonia in n/total (83%) cases with LGI1-Abs and myoclonus in all cases with GLY-R-Abs. Tumours were detected in 25% with NMDAR-Abs.
Immunotherapy was used in 25/45 (55%) of cases, most commonly when a neuronal synaptic extracellular Ab was present (94%). Prednisolone (80%) and IVIg (55%) were the commonly used 1st and 2nd line treatments. Chorea and paroxysmal dystonia showed complete remission with immunotherapy. The median times to diagnosis of autoimmune encephalitis were shorter when movement disorders were present with NMDAR-Ab (13 vs. 133 weeks) and LGI1-Ab (4 vs. 63 weeks).
Conclusion: Half of the patients with autoimmune encephalitis and a neuronal Ab presented with a movement disorder. This clinical feature appears to help with the diagnosis. Associated hyperkinetic movement disorders respond favourably to immunotherapy.
To cite this abstract in AMA style:V. Karthikeayan, A. Randall, E. Jackson, S. Huda, M. Bonello. The clinical spectrum of movement disorders associated with neuronal antibodies [abstract]. Mov Disord. 2020; 35 (suppl 1). https://www.mdsabstracts.org/abstract/the-clinical-spectrum-of-movement-disorders-associated-with-neuronal-antibodies/. Accessed December 2, 2023.
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