GAD1 and Smith-Magenis syndrome: The second hallmark observation was the description of autoantibodies against GAD by Solimena et al. [2] who detected anti-GAD antibodies in both serum and cerebrospinal fluid, pointed out an immunological connection between SMS and DM1 and concluded that the clinical manifestations of SMS are related to disruption of GABAergic pathways [2], a notion still valid today.