TGM2 and diabetes mellitus: Although it is still the use of celiac-related antibody detection tests as the first step of screening in symptomatic patients [3], however, the increase in serum levels of anti-tTG in various diseases and conditions such as autoimmune diseases, diabetes mellitus, infections, tumors, injuries myocardium, liver disorders, and psoriasis are observed without any evidence of CD, which can be an obstacle for the differential diagnosis of CD and make its diagnosis challenging [14–19].