Anti-glutamic acid decarboxylase-65 (anti-GAD65) autoantibodies have been identified in a variety of rare neurologic disorders; (1–3) most frequently in stiff person syndrome (SPS), a condition characterized by muscle rigidity and overlying painful spasms, typically affecting the axial and limb musculature (3, 4). The gene discussed is GAD2; the disease is stiff-person syndrome.