These diseases share key immunological features, including the production of organ‐specific autoantibodies—such as anti‐thyroid peroxidase antibodies (TPOAb) in autoimmune thyroiditis and glutamic acid decarboxylase antibodies (GADAb) in T1DM—and infiltration of T and B lymphocytes into affected organs [25]. The gene discussed is TPO; the disease is type 1 diabetes mellitus.