Indeed, the diagnostic criteria for SPS are the presence of stiffness in limb and axial muscles evoked by tactile and auditory stimuli, EMG evidence of continuous motor unit activity in agonist and antagonist muscles, positivity for anti-GAD antibodies in serum and/or CSF, and the exclusion of other neurological and non-neurological diseases that can cause muscle stiffness (1, 3). The gene discussed is GAD1; the disease is stiff-person syndrome.