For example, human endogenous intestinal enzymes and microbial transglutaminases (tTg, mTg) induce multiple neo-epitopes on the Tg-peptide docked complex or citrullination by peptidylarginine deiminase resulting in the formation of autoantibodies in celiac disease and rheumatoid arthritis, respectively. The gene discussed is TGM2; the disease is celiac disease.