To the editor:

We read with great interest the article “Isolated Chorea Associated with LGI1 Antibody ” (LGI1, leucine-rich glioma inactivated 1) by Ram-dhani and Frucht.1 The authors presented an important clinical obser-vation about a treatable etiology of chorea in a 53-year-old male, in whom an underlying tumor could not be detected. By presenting a case vignette of hemichorea associated with antibodies against contactin-associated protein 2 (CASPR2), we wish to emphasize the relationship between a movement disorder and an autoantibody. In our patient, lung cancer was detected. A 75-year-old female developed choreiform movement disorder, predominantly affecting the left limbs and the left side of the face. She took no neuroleptic drugs and reported that she had been smoking for about 50 years. Her family history was unremarkable. Cranial magnetic resonance images and serum chemistry, including liver enzymes, com-plete blood count, thyroid function, and cerebrospinal fluid analysi