In the present study, FT1D was independently associated with a higher likelihood of positivity for extra-pancreatic autoantibodies (OR = 1.78, p = 0.003) and anti-tissue transglutaminase antibodies (OR = 1.64, p = 0.031), indicating increased susceptibility to coexisting autoimmune disorders—particularly celiac disease. This evidence concerns the gene TGM2 and autoimmune disease.