ATP1A3: an unusual antigen to consider in patients with subacute ataxia and vertical gaze palsy.

The anti-ATP1A3 antibody seems to be directed against a neuronal and cardiac surface protein of the proton ATPase. It was recently identified in a patient with a paraneoplastic syndrome characterized by cerebellar, neuro-ophthalmologic and other neurological symptoms. We report another patient with a similar clinical and radiological syndrome but with a different associated tumor and outcome.