TFRC and diabetes mellitus: Furthermore, although not differentially O-GlcNAc-modified in diabetes compared to the BMI-matched controls, the TfR was identified in all placental O-GlcNAcomes, with 5 modified residues (Table 3), and its ligand, transferrin, was more O-GlcNAcyalted (19.5-fold) in placentas from women with T2D (Supplementary Table S3).