TPO and autoimmune thyroid disease: It is known that almost 15%–30% of Type1 DM subjects are associated with autoimmune thyroid disease (Hashimoto's or Graves' disease), and 5%–10% are diagnosed with autoimmune gastritis and/or pernicious anemia (AIG /PA), These diseases are characterized by the presence of autoantibodies against thyroid peroxidase (for Hashimoto's thyroiditis), TSH receptor (for Graves' disease), parietal cell or intrinsic factor (for AIG /PA), and 21‐hydroxylase (for AD).11