Autoantibody-associated movement disorders.

Autoantibodies to the extracellular domain of neuronal proteins cause different neurological conditions with movement disorders as a prominent feature. We reviewed the literature of autoantibody-mediated and autoantibody-associated diseases focusing on anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis, autoimmune basal ganglia encephalitis, Sydenham chorea, and the rare syndrome of progressive encephalomyelitis with rigidity and myoclonus. NMDAR encephalitis is a diffuse encephalitis with psychiatric and cognitive features associated with autoantibodies against the NR1 subunit of the NMDAR. The movement disorder phenotype is diverse and often generalized in young children. Although orofacial dyskinesia was the initial movement phenotype, chorea, dystonia, catatonia, and stereotypical movements are now described. The stereotypical movements can be bizarre and include cycling movements and compulsive self-injurious behavior. Autoimmune basal ganglia encephalitis is an inflammatory encephalitis localizing to the basal ganglia that is sometimes associated with serum antibodies against dopamine-2 receptor. Although psychiatric features are common, the dominant problem is a movement disorder, with dystonia-parkinsonism being characteristic. Sydenham chorea is the prototypic poststreptococcal autoimmune neuropsychiatric disorder and several autoantibodies may be involved in disease generation. The syndrome is characterized by a pure chorea, although hypotonia, dysarthria, and emotional lability are common. Progressive encephalomyelitis with rigidity and myoclonus is a rare autoimmune disorder causing rigidity, stimulus sensitive spasms, and myoclonus of nonepileptic origin and is associated with autoantibodies of multiple types including those against the glycine receptor. These disorders are important to recognize and diagnose, as immune therapy can shorten disease duration and improve outcome.