To investigate the genes involved in autoantibody production, we measured two T1D-associated anti-islet autoantibodies: glutamate decarboxylase (GADA, n = 2,506) and insulinoma-associated antigen 2 (IA-2A, n = 2,498) in plasma samples from T1D cases. The gene discussed is GLUL; the disease is type 1 diabetes mellitus.