In particular, TG2-catalyzed deamidation of specific glutamines in dietary gliadin, the main proteic component of wheat, seems to play a key role in the pathogenetic mechanism of celiac disease (CD), an inflammatory condition of the small intestine characterized by a specific immune response to peptides derived from ingested gliadin in genetically-susceptible individuals [13], [14]. The gene discussed is TGM2; the disease is Cowden disease.