Antibodies against the juxtaparanodal protein CASPR2 are associated with a variety of movement disorders including neuromyotonia, chorea, ataxia, and a syndrome of orthostatic myoclonus.3, 65 Many of these typically occur in the context of an encephalopathy that is similar to that associated with LGI1 antibodies. The gene discussed is CNTNAP2; the disease is cerebellar ataxia.