TGM2 and type 1 diabetes mellitus: To investigate if Tgm2 is expressed and active in the thymus and to provide further insight on the mechanism underlying the reported immunogenicity of deamidated peptides in T1D, we investigated transcriptional expression and activity levels of Tgm2 in the thymus of 6- and 10-week-old C57BL/6 and NOD mice.