T1DM, type 1 diabetes mellitus; CD, celiac disease; BPCD, biopsy-proven celiac disease; anti-tTG, anti-tissue transglutaminase antibodies; US, United States; HbA1c, hemoglobin A1c; GFD, gluten-free diet. The gene discussed is TGM2; the disease is type 1 diabetes mellitus.