Movement Disorders in Antibody-Associated Neurologic Diseases: A Nationwide Study.

Area of Science:

• Neurology
• Immunology
• Neuroimmunology

Background:

• Antibody-associated neurologic diseases frequently manifest with movement disorders (MDs).
• The precise incidence and clinical progression of MDs across various antibody-associated disease subtypes are not well-established.

Purpose of the Study:

• To investigate the frequency and clinical characteristics of movement disorders in a large cohort of patients with antibody-associated neurologic diseases.
• To identify novel associations between specific antibodies and movement disorders.
• To provide guidance on antibody testing strategies for different movement disorder phenotypes.

Main Methods:

• Retrospective nationwide observational study.
• Analysis of a large cohort of Dutch patients diagnosed with antibody-associated neurologic diseases between January 2000 and April 2024.
• Detailed description and categorization of movement disorders observed in the cohort.

Main Results:

• Movement disorders were identified in 42% (459/1,140) of patients, frequently presenting as the initial or predominant symptom.
• Cerebellar ataxia was the most common MD (235 patients), particularly with HuD and GAD65 antibodies.
• Other common MDs included dyskinesia and myoclonus (primarily NMDAR-associated) and stiff-person syndrome (GAD65-associated).
• Novel associations were found, such as chorea/dystonia in anti-kelch like protein 11-associated brainstem encephalitis and episodic ataxia in anti-LGI1 and anti-GAD65 syndromes.

Conclusions:

• Movement disorders are a significant clinical feature of antibody-associated neurologic diseases, with prevalence varying by antibody target.
• MDs can be the presenting or sole neurological manifestation, underscoring their importance in diagnosis.
• The findings support including antibody-associated neurologic diseases in the differential diagnosis of new-onset MDs and inform targeted antibody testing.