Anti-CV2/CRMP5 IgG target an intracellular antigen (collapsin response mediator protein) and have been reported in the setting of various paraneoplastic syndromes, including peripheral neuropathy, cranial neuropathy, gastroparesis, encephalitis, cerebellar ataxia, myelopathy, and chorea. The gene discussed is DPYSL5; the disease is Chorea.