Thus, in this case, as soon as T1DM is diagnosed, screening for CD should be made by measuring IgA tTG and proven serum IgA levels within the normal range. Immunoglobulin G (IgG) tTG or IgG deamidated gliadin antibodies should be measured if IgA levels were deficient. This evidence concerns the gene CD79A and type 1 diabetes mellitus.