Unidirectional Palsy of Torsional Saccades in Ataxia Associated with Anti-GAD Antibody

Antibodies against glutamic acid decarboxylase (GAD) are associated with various neurological syndromes including cerebellar ataxia and ocular motor abnormalities. We report a 67-year-old man with progressive dizziness and imbalance, who exhibited spontaneous downbeat and torsional nystagmus, normal vertical saccades, and a unilateral loss of torsional saccades during head tilting. Serum anti-GAD antibody was elevated. Tests for other autoantibodies and genes responsible for spinocerebellar atax