GAD1 and stiff-person syndrome: Autoimmune and immune-mediated mimics of anti-GAD-associated SPS with overlapping oculomotor signs span the broader spectrum of autoimmune cerebellar ataxias (e.g., gluten ataxia, post-infectious forms, primary autoimmune cerebellar ataxia) as well as Miller–Fisher syndrome, opsoclonus–myoclonus syndrome, and paraneoplastic cerebellar degeneration [20].