GAD2 and stiff-person syndrome: SPS is based on a clinical diagnosis of (a) classical features, including muscular rigidity, EMG confirmation of co-contraction of agonist and antagonist muscles, episodic unexpected spasms, and absence of other neurologic disease that could explain this etiology; (b) supportive features, including anti-GAD65 antibodies, clinical response to benzodiazepines, and other endocrinopathies [1].